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patch(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes a PATCH request on the provided path and returns a Response object. Useful for testing RESTful interfaces. The follow, secure and extra arguments act the same as for Client.get(). | django.topics.testing.tools#django.test.Client.patch |
post(path, data=None, content_type=MULTIPART_CONTENT, follow=False, secure=False, **extra)
Makes a POST request on the provided path and returns a Response object, which is documented below. The key-value pairs in the data dictionary are used to submit POST data. For example: >>> c = Client()
>>> c.post('/login/', {'name': 'fred', 'passwd': 'secret'})
…will result in the evaluation of a POST request to this URL: /login/
…with this POST data: name=fred&passwd=secret
If you provide content_type as application/json, the data is serialized using json.dumps() if it’s a dict, list, or tuple. Serialization is performed with DjangoJSONEncoder by default, and can be overridden by providing a json_encoder argument to Client. This serialization also happens for put(), patch(), and delete() requests. If you provide any other content_type (e.g. text/xml for an XML payload), the contents of data are sent as-is in the POST request, using content_type in the HTTP Content-Type header. If you don’t provide a value for content_type, the values in data will be transmitted with a content type of multipart/form-data. In this case, the key-value pairs in data will be encoded as a multipart message and used to create the POST data payload. To submit multiple values for a given key – for example, to specify the selections for a <select multiple> – provide the values as a list or tuple for the required key. For example, this value of data would submit three selected values for the field named choices: {'choices': ('a', 'b', 'd')}
Submitting files is a special case. To POST a file, you need only provide the file field name as a key, and a file handle to the file you wish to upload as a value. For example: >>> c = Client()
>>> with open('wishlist.doc', 'rb') as fp:
... c.post('/customers/wishes/', {'name': 'fred', 'attachment': fp})
(The name attachment here is not relevant; use whatever name your file-processing code expects.) You may also provide any file-like object (e.g., StringIO or BytesIO) as a file handle. If you’re uploading to an ImageField, the object needs a name attribute that passes the validate_image_file_extension validator. For example: >>> from io import BytesIO
>>> img = BytesIO(b'mybinarydata')
>>> img.name = 'myimage.jpg'
Note that if you wish to use the same file handle for multiple post() calls then you will need to manually reset the file pointer between posts. The easiest way to do this is to manually close the file after it has been provided to post(), as demonstrated above. You should also ensure that the file is opened in a way that allows the data to be read. If your file contains binary data such as an image, this means you will need to open the file in rb (read binary) mode. The extra argument acts the same as for Client.get(). If the URL you request with a POST contains encoded parameters, these parameters will be made available in the request.GET data. For example, if you were to make the request: >>> c.post('/login/?visitor=true', {'name': 'fred', 'passwd': 'secret'})
… the view handling this request could interrogate request.POST to retrieve the username and password, and could interrogate request.GET to determine if the user was a visitor. If you set follow to True the client will follow any redirects and a redirect_chain attribute will be set in the response object containing tuples of the intermediate urls and status codes. If you set secure to True the client will emulate an HTTPS request. | django.topics.testing.tools#django.test.Client.post |
put(path, data='', content_type='application/octet-stream', follow=False, secure=False, **extra)
Makes a PUT request on the provided path and returns a Response object. Useful for testing RESTful interfaces. When data is provided, it is used as the request body, and a Content-Type header is set to content_type. The follow, secure and extra arguments act the same as for Client.get(). | django.topics.testing.tools#django.test.Client.put |
Client.session
A dictionary-like object containing session information. See the session documentation for full details. To modify the session and then save it, it must be stored in a variable first (because a new SessionStore is created every time this property is accessed): def test_something(self):
session = self.client.session
session['somekey'] = 'test'
session.save() | django.topics.testing.tools#django.test.Client.session |
trace(path, follow=False, secure=False, **extra)
Makes a TRACE request on the provided path and returns a Response object. Useful for simulating diagnostic probes. Unlike the other request methods, data is not provided as a keyword parameter in order to comply with RFC 7231#section-4.3.8, which mandates that TRACE requests must not have a body. The follow, secure, and extra arguments act the same as for Client.get(). | django.topics.testing.tools#django.test.Client.trace |
class LiveServerTestCase | django.topics.testing.tools#django.test.LiveServerTestCase |
modify_settings() | django.topics.testing.tools#django.test.modify_settings |
override_settings() | django.topics.testing.tools#django.test.override_settings |
class RequestFactory | django.topics.testing.advanced#django.test.RequestFactory |
class Response
client
The test client that was used to make the request that resulted in the response.
content
The body of the response, as a bytestring. This is the final page content as rendered by the view, or any error message.
context
The template Context instance that was used to render the template that produced the response content. If the rendered page used multiple templates, then context will be a list of Context objects, in the order in which they were rendered. Regardless of the number of templates used during rendering, you can retrieve context values using the [] operator. For example, the context variable name could be retrieved using: >>> response = client.get('/foo/')
>>> response.context['name']
'Arthur'
Not using Django templates? This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, context_data may be a suitable alternative on responses with that attribute.
exc_info
A tuple of three values that provides information about the unhandled exception, if any, that occurred during the view. The values are (type, value, traceback), the same as returned by Python’s sys.exc_info(). Their meanings are:
type: The type of the exception.
value: The exception instance.
traceback: A traceback object which encapsulates the call stack at the point where the exception originally occurred. If no exception occurred, then exc_info will be None.
json(**kwargs)
The body of the response, parsed as JSON. Extra keyword arguments are passed to json.loads(). For example: >>> response = client.get('/foo/')
>>> response.json()['name']
'Arthur'
If the Content-Type header is not "application/json", then a ValueError will be raised when trying to parse the response.
request
The request data that stimulated the response.
wsgi_request
The WSGIRequest instance generated by the test handler that generated the response.
status_code
The HTTP status of the response, as an integer. For a full list of defined codes, see the IANA status code registry.
templates
A list of Template instances used to render the final content, in the order they were rendered. For each template in the list, use template.name to get the template’s file name, if the template was loaded from a file. (The name is a string such as 'admin/index.html'.) Not using Django templates? This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, template_name may be a suitable alternative if you only need the name of the template used for rendering.
resolver_match
An instance of ResolverMatch for the response. You can use the func attribute, for example, to verify the view that served the response: # my_view here is a function based view
self.assertEqual(response.resolver_match.func, my_view)
# class-based views need to be compared by name, as the functions
# generated by as_view() won't be equal
self.assertEqual(response.resolver_match.func.__name__, MyView.as_view().__name__)
If the given URL is not found, accessing this attribute will raise a Resolver404 exception. | django.topics.testing.tools#django.test.Response |
client
The test client that was used to make the request that resulted in the response. | django.topics.testing.tools#django.test.Response.client |
content
The body of the response, as a bytestring. This is the final page content as rendered by the view, or any error message. | django.topics.testing.tools#django.test.Response.content |
context
The template Context instance that was used to render the template that produced the response content. If the rendered page used multiple templates, then context will be a list of Context objects, in the order in which they were rendered. Regardless of the number of templates used during rendering, you can retrieve context values using the [] operator. For example, the context variable name could be retrieved using: >>> response = client.get('/foo/')
>>> response.context['name']
'Arthur'
Not using Django templates? This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, context_data may be a suitable alternative on responses with that attribute. | django.topics.testing.tools#django.test.Response.context |
exc_info
A tuple of three values that provides information about the unhandled exception, if any, that occurred during the view. The values are (type, value, traceback), the same as returned by Python’s sys.exc_info(). Their meanings are:
type: The type of the exception.
value: The exception instance.
traceback: A traceback object which encapsulates the call stack at the point where the exception originally occurred. If no exception occurred, then exc_info will be None. | django.topics.testing.tools#django.test.Response.exc_info |
json(**kwargs)
The body of the response, parsed as JSON. Extra keyword arguments are passed to json.loads(). For example: >>> response = client.get('/foo/')
>>> response.json()['name']
'Arthur'
If the Content-Type header is not "application/json", then a ValueError will be raised when trying to parse the response. | django.topics.testing.tools#django.test.Response.json |
request
The request data that stimulated the response. | django.topics.testing.tools#django.test.Response.request |
resolver_match
An instance of ResolverMatch for the response. You can use the func attribute, for example, to verify the view that served the response: # my_view here is a function based view
self.assertEqual(response.resolver_match.func, my_view)
# class-based views need to be compared by name, as the functions
# generated by as_view() won't be equal
self.assertEqual(response.resolver_match.func.__name__, MyView.as_view().__name__)
If the given URL is not found, accessing this attribute will raise a Resolver404 exception. | django.topics.testing.tools#django.test.Response.resolver_match |
status_code
The HTTP status of the response, as an integer. For a full list of defined codes, see the IANA status code registry. | django.topics.testing.tools#django.test.Response.status_code |
templates
A list of Template instances used to render the final content, in the order they were rendered. For each template in the list, use template.name to get the template’s file name, if the template was loaded from a file. (The name is a string such as 'admin/index.html'.) Not using Django templates? This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, template_name may be a suitable alternative if you only need the name of the template used for rendering. | django.topics.testing.tools#django.test.Response.templates |
wsgi_request
The WSGIRequest instance generated by the test handler that generated the response. | django.topics.testing.tools#django.test.Response.wsgi_request |
class DiscoverRunner(pattern='test*.py', top_level=None, verbosity=1, interactive=True, failfast=False, keepdb=False, reverse=False, debug_mode=False, debug_sql=False, parallel=0, tags=None, exclude_tags=None, test_name_patterns=None, pdb=False, buffer=False, enable_faulthandler=True, timing=True, shuffle=False, logger=None, **kwargs)
DiscoverRunner will search for tests in any file matching pattern. top_level can be used to specify the directory containing your top-level Python modules. Usually Django can figure this out automatically, so it’s not necessary to specify this option. If specified, it should generally be the directory containing your manage.py file. verbosity determines the amount of notification and debug information that will be printed to the console; 0 is no output, 1 is normal output, and 2 is verbose output. If interactive is True, the test suite has permission to ask the user for instructions when the test suite is executed. An example of this behavior would be asking for permission to delete an existing test database. If interactive is False, the test suite must be able to run without any manual intervention. If failfast is True, the test suite will stop running after the first test failure is detected. If keepdb is True, the test suite will use the existing database, or create one if necessary. If False, a new database will be created, prompting the user to remove the existing one, if present. If reverse is True, test cases will be executed in the opposite order. This could be useful to debug tests that aren’t properly isolated and have side effects. Grouping by test class is preserved when using this option. This option can be used in conjunction with --shuffle to reverse the order for a particular random seed. debug_mode specifies what the DEBUG setting should be set to prior to running tests. parallel specifies the number of processes. If parallel is greater than 1, the test suite will run in parallel processes. If there are fewer test cases than configured processes, Django will reduce the number of processes accordingly. Each process gets its own database. This option requires the third-party tblib package to display tracebacks correctly. tags can be used to specify a set of tags for filtering tests. May be combined with exclude_tags. exclude_tags can be used to specify a set of tags for excluding tests. May be combined with tags. If debug_sql is True, failing test cases will output SQL queries logged to the django.db.backends logger as well as the traceback. If verbosity is 2, then queries in all tests are output. test_name_patterns can be used to specify a set of patterns for filtering test methods and classes by their names. If pdb is True, a debugger (pdb or ipdb) will be spawned at each test error or failure. If buffer is True, outputs from passing tests will be discarded. If enable_faulthandler is True, faulthandler will be enabled. If timing is True, test timings, including database setup and total run time, will be shown. If shuffle is an integer, test cases will be shuffled in a random order prior to execution, using the integer as a random seed. If shuffle is None, the seed will be generated randomly. In both cases, the seed will be logged and set to self.shuffle_seed prior to running tests. This option can be used to help detect tests that aren’t properly isolated. Grouping by test class is preserved when using this option. logger can be used to pass a Python Logger object. If provided, the logger will be used to log messages instead of printing to the console. The logger object will respect its logging level rather than the verbosity. Django may, from time to time, extend the capabilities of the test runner by adding new arguments. The **kwargs declaration allows for this expansion. If you subclass DiscoverRunner or write your own test runner, ensure it accepts **kwargs. Your test runner may also define additional command-line options. Create or override an add_arguments(cls, parser) class method and add custom arguments by calling parser.add_argument() inside the method, so that the test command will be able to use those arguments. New in Django 3.2: The enable_faulthandler and timing arguments were added. New in Django 4.0: The logger and shuffle arguments were added. | django.topics.testing.advanced#django.test.runner.DiscoverRunner |
DiscoverRunner.build_suite(test_labels=None, **kwargs)
Constructs a test suite that matches the test labels provided. test_labels is a list of strings describing the tests to be run. A test label can take one of four forms:
path.to.test_module.TestCase.test_method – Run a single test method in a test case.
path.to.test_module.TestCase – Run all the test methods in a test case.
path.to.module – Search for and run all tests in the named Python package or module.
path/to/directory – Search for and run all tests below the named directory. If test_labels has a value of None, the test runner will search for tests in all files below the current directory whose names match its pattern (see above). Deprecated since version 4.0: extra_tests is a list of extra TestCase instances to add to the suite that is executed by the test runner. These extra tests are run in addition to those discovered in the modules listed in test_labels. Returns a TestSuite instance ready to be run. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.build_suite |
DiscoverRunner.get_test_runner_kwargs()
Returns the keyword arguments to instantiate the DiscoverRunner.test_runner with. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.get_test_runner_kwargs |
DiscoverRunner.log(msg, level=None)
New in Django 4.0. If a logger is set, logs the message at the given integer logging level (e.g. logging.DEBUG, logging.INFO, or logging.WARNING). Otherwise, the message is printed to the console, respecting the current verbosity. For example, no message will be printed if the verbosity is 0, INFO and above will be printed if the verbosity is at least 1, and DEBUG will be printed if it is at least 2. The level defaults to logging.INFO. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.log |
DiscoverRunner.run_checks(databases)
Runs the system checks on the test databases. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.run_checks |
DiscoverRunner.run_suite(suite, **kwargs)
Runs the test suite. Returns the result produced by the running the test suite. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.run_suite |
DiscoverRunner.run_tests(test_labels, **kwargs)
Run the test suite. test_labels allows you to specify which tests to run and supports several formats (see DiscoverRunner.build_suite() for a list of supported formats). Deprecated since version 4.0: extra_tests is a list of extra TestCase instances to add to the suite that is executed by the test runner. These extra tests are run in addition to those discovered in the modules listed in test_labels. This method should return the number of tests that failed. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.run_tests |
DiscoverRunner.setup_databases(**kwargs)
Creates the test databases by calling setup_databases(). | django.topics.testing.advanced#django.test.runner.DiscoverRunner.setup_databases |
DiscoverRunner.setup_test_environment(**kwargs)
Sets up the test environment by calling setup_test_environment() and setting DEBUG to self.debug_mode (defaults to False). | django.topics.testing.advanced#django.test.runner.DiscoverRunner.setup_test_environment |
DiscoverRunner.suite_result(suite, result, **kwargs)
Computes and returns a return code based on a test suite, and the result from that test suite. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.suite_result |
DiscoverRunner.teardown_databases(old_config, **kwargs)
Destroys the test databases, restoring pre-test conditions by calling teardown_databases(). | django.topics.testing.advanced#django.test.runner.DiscoverRunner.teardown_databases |
DiscoverRunner.teardown_test_environment(**kwargs)
Restores the pre-test environment. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.teardown_test_environment |
DiscoverRunner.test_loader
This is the class that loads tests, whether from TestCases or modules or otherwise and bundles them into test suites for the runner to execute. By default it is set to unittest.defaultTestLoader. You can override this attribute if your tests are going to be loaded in unusual ways. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.test_loader |
DiscoverRunner.test_runner
This is the class of the low-level test runner which is used to execute the individual tests and format the results. By default it is set to unittest.TextTestRunner. Despite the unfortunate similarity in naming conventions, this is not the same type of class as DiscoverRunner, which covers a broader set of responsibilities. You can override this attribute to modify the way tests are run and reported. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.test_runner |
DiscoverRunner.test_suite
The class used to build the test suite. By default it is set to unittest.TestSuite. This can be overridden if you wish to implement different logic for collecting tests. | django.topics.testing.advanced#django.test.runner.DiscoverRunner.test_suite |
django.test.signals.setting_changed | django.ref.signals#django.test.signals.setting_changed |
django.test.signals.template_rendered | django.ref.signals#django.test.signals.template_rendered |
class SimpleTestCase | django.topics.testing.tools#django.test.SimpleTestCase |
SimpleTestCase.assertContains(response, text, count=None, status_code=200, msg_prefix='', html=False)
Asserts that a response produced the given status_code and that text appears in its content. If count is provided, text must occur exactly count times in the response. Set html to True to handle text as HTML. The comparison with the response content will be based on HTML semantics instead of character-by-character equality. Whitespace is ignored in most cases, attribute ordering is not significant. See assertHTMLEqual() for more details. | django.topics.testing.tools#django.test.SimpleTestCase.assertContains |
SimpleTestCase.assertFieldOutput(fieldclass, valid, invalid, field_args=None, field_kwargs=None, empty_value='')
Asserts that a form field behaves correctly with various inputs.
Parameters:
fieldclass – the class of the field to be tested.
valid – a dictionary mapping valid inputs to their expected cleaned values.
invalid – a dictionary mapping invalid inputs to one or more raised error messages.
field_args – the args passed to instantiate the field.
field_kwargs – the kwargs passed to instantiate the field.
empty_value – the expected clean output for inputs in empty_values. For example, the following code tests that an EmailField accepts [email protected] as a valid email address, but rejects aaa with a reasonable error message: self.assertFieldOutput(EmailField, {'[email protected]': '[email protected]'}, {'aaa': ['Enter a valid email address.']}) | django.topics.testing.tools#django.test.SimpleTestCase.assertFieldOutput |
SimpleTestCase.assertFormError(response, form, field, errors, msg_prefix='')
Asserts that a field on a form raises the provided list of errors when rendered on the form. response must be a response instance returned by the test client. form is the name the Form instance was given in the template context of the response. field is the name of the field on the form to check. If field has a value of None, non-field errors (errors you can access via form.non_field_errors()) will be checked. errors is an error string, or a list of error strings, that are expected as a result of form validation. | django.topics.testing.tools#django.test.SimpleTestCase.assertFormError |
SimpleTestCase.assertFormsetError(response, formset, form_index, field, errors, msg_prefix='')
Asserts that the formset raises the provided list of errors when rendered. response must be a response instance returned by the test client. formset is the name the Formset instance was given in the template context of the response. form_index is the number of the form within the Formset. If form_index has a value of None, non-form errors (errors you can access via formset.non_form_errors()) will be checked. field is the name of the field on the form to check. If field has a value of None, non-field errors (errors you can access via form.non_field_errors()) will be checked. errors is an error string, or a list of error strings, that are expected as a result of form validation. | django.topics.testing.tools#django.test.SimpleTestCase.assertFormsetError |
SimpleTestCase.assertHTMLEqual(html1, html2, msg=None)
Asserts that the strings html1 and html2 are equal. The comparison is based on HTML semantics. The comparison takes following things into account: Whitespace before and after HTML tags is ignored. All types of whitespace are considered equivalent. All open tags are closed implicitly, e.g. when a surrounding tag is closed or the HTML document ends. Empty tags are equivalent to their self-closing version. The ordering of attributes of an HTML element is not significant. Boolean attributes (like checked) without an argument are equal to attributes that equal in name and value (see the examples). Text, character references, and entity references that refer to the same character are equivalent. The following examples are valid tests and don’t raise any AssertionError: self.assertHTMLEqual(
'<p>Hello <b>'world'!</p>',
'''<p>
Hello <b>'world'! </b>
</p>'''
)
self.assertHTMLEqual(
'<input type="checkbox" checked="checked" id="id_accept_terms" />',
'<input id="id_accept_terms" type="checkbox" checked>'
)
html1 and html2 must contain HTML. An AssertionError will be raised if one of them cannot be parsed. Output in case of error can be customized with the msg argument. Changed in Django 4.0: In older versions, any attribute (not only boolean attributes) without a value was considered equal to an attribute with the same name and value. | django.topics.testing.tools#django.test.SimpleTestCase.assertHTMLEqual |
SimpleTestCase.assertHTMLNotEqual(html1, html2, msg=None)
Asserts that the strings html1 and html2 are not equal. The comparison is based on HTML semantics. See assertHTMLEqual() for details. html1 and html2 must contain HTML. An AssertionError will be raised if one of them cannot be parsed. Output in case of error can be customized with the msg argument. | django.topics.testing.tools#django.test.SimpleTestCase.assertHTMLNotEqual |
SimpleTestCase.assertInHTML(needle, haystack, count=None, msg_prefix='')
Asserts that the HTML fragment needle is contained in the haystack one. If the count integer argument is specified, then additionally the number of needle occurrences will be strictly verified. Whitespace in most cases is ignored, and attribute ordering is not significant. See assertHTMLEqual() for more details. | django.topics.testing.tools#django.test.SimpleTestCase.assertInHTML |
SimpleTestCase.assertJSONEqual(raw, expected_data, msg=None)
Asserts that the JSON fragments raw and expected_data are equal. Usual JSON non-significant whitespace rules apply as the heavyweight is delegated to the json library. Output in case of error can be customized with the msg argument. | django.topics.testing.tools#django.test.SimpleTestCase.assertJSONEqual |
SimpleTestCase.assertJSONNotEqual(raw, expected_data, msg=None)
Asserts that the JSON fragments raw and expected_data are not equal. See assertJSONEqual() for further details. Output in case of error can be customized with the msg argument. | django.topics.testing.tools#django.test.SimpleTestCase.assertJSONNotEqual |
SimpleTestCase.assertNotContains(response, text, status_code=200, msg_prefix='', html=False)
Asserts that a response produced the given status_code and that text does not appear in its content. Set html to True to handle text as HTML. The comparison with the response content will be based on HTML semantics instead of character-by-character equality. Whitespace is ignored in most cases, attribute ordering is not significant. See assertHTMLEqual() for more details. | django.topics.testing.tools#django.test.SimpleTestCase.assertNotContains |
SimpleTestCase.assertRaisesMessage(expected_exception, expected_message, callable, *args, **kwargs)
SimpleTestCase.assertRaisesMessage(expected_exception, expected_message)
Asserts that execution of callable raises expected_exception and that expected_message is found in the exception’s message. Any other outcome is reported as a failure. It’s a simpler version of unittest.TestCase.assertRaisesRegex() with the difference that expected_message isn’t treated as a regular expression. If only the expected_exception and expected_message parameters are given, returns a context manager so that the code being tested can be written inline rather than as a function: with self.assertRaisesMessage(ValueError, 'invalid literal for int()'):
int('a') | django.topics.testing.tools#django.test.SimpleTestCase.assertRaisesMessage |
SimpleTestCase.assertRedirects(response, expected_url, status_code=302, target_status_code=200, msg_prefix='', fetch_redirect_response=True)
Asserts that the response returned a status_code redirect status, redirected to expected_url (including any GET data), and that the final page was received with target_status_code. If your request used the follow argument, the expected_url and target_status_code will be the url and status code for the final point of the redirect chain. If fetch_redirect_response is False, the final page won’t be loaded. Since the test client can’t fetch external URLs, this is particularly useful if expected_url isn’t part of your Django app. Scheme is handled correctly when making comparisons between two URLs. If there isn’t any scheme specified in the location where we are redirected to, the original request’s scheme is used. If present, the scheme in expected_url is the one used to make the comparisons to. | django.topics.testing.tools#django.test.SimpleTestCase.assertRedirects |
SimpleTestCase.assertTemplateNotUsed(response, template_name, msg_prefix='')
Asserts that the template with the given name was not used in rendering the response. You can use this as a context manager in the same way as assertTemplateUsed(). | django.topics.testing.tools#django.test.SimpleTestCase.assertTemplateNotUsed |
SimpleTestCase.assertTemplateUsed(response, template_name, msg_prefix='', count=None)
Asserts that the template with the given name was used in rendering the response. response must be a response instance returned by the test client. template_name should be a string such as 'admin/index.html'. The count argument is an integer indicating the number of times the template should be rendered. Default is None, meaning that the template should be rendered one or more times. You can use this as a context manager, like this: with self.assertTemplateUsed('index.html'):
render_to_string('index.html')
with self.assertTemplateUsed(template_name='index.html'):
render_to_string('index.html') | django.topics.testing.tools#django.test.SimpleTestCase.assertTemplateUsed |
SimpleTestCase.assertURLEqual(url1, url2, msg_prefix='')
Asserts that two URLs are the same, ignoring the order of query string parameters except for parameters with the same name. For example, /path/?x=1&y=2 is equal to /path/?y=2&x=1, but /path/?a=1&a=2 isn’t equal to /path/?a=2&a=1. | django.topics.testing.tools#django.test.SimpleTestCase.assertURLEqual |
SimpleTestCase.assertWarnsMessage(expected_warning, expected_message, callable, *args, **kwargs)
SimpleTestCase.assertWarnsMessage(expected_warning, expected_message)
Analogous to SimpleTestCase.assertRaisesMessage() but for assertWarnsRegex() instead of assertRaisesRegex(). | django.topics.testing.tools#django.test.SimpleTestCase.assertWarnsMessage |
SimpleTestCase.assertXMLEqual(xml1, xml2, msg=None)
Asserts that the strings xml1 and xml2 are equal. The comparison is based on XML semantics. Similarly to assertHTMLEqual(), the comparison is made on parsed content, hence only semantic differences are considered, not syntax differences. When invalid XML is passed in any parameter, an AssertionError is always raised, even if both strings are identical. XML declaration, document type, processing instructions, and comments are ignored. Only the root element and its children are compared. Output in case of error can be customized with the msg argument. | django.topics.testing.tools#django.test.SimpleTestCase.assertXMLEqual |
SimpleTestCase.assertXMLNotEqual(xml1, xml2, msg=None)
Asserts that the strings xml1 and xml2 are not equal. The comparison is based on XML semantics. See assertXMLEqual() for details. Output in case of error can be customized with the msg argument. | django.topics.testing.tools#django.test.SimpleTestCase.assertXMLNotEqual |
SimpleTestCase.client | django.topics.testing.tools#django.test.SimpleTestCase.client |
SimpleTestCase.client_class | django.topics.testing.tools#django.test.SimpleTestCase.client_class |
SimpleTestCase.databases
SimpleTestCase disallows database queries by default. This helps to avoid executing write queries which will affect other tests since each SimpleTestCase test isn’t run in a transaction. If you aren’t concerned about this problem, you can disable this behavior by setting the databases class attribute to '__all__' on your test class. | django.topics.testing.tools#django.test.SimpleTestCase.databases |
SimpleTestCase.modify_settings() | django.topics.testing.tools#django.test.SimpleTestCase.modify_settings |
SimpleTestCase.settings() | django.topics.testing.tools#django.test.SimpleTestCase.settings |
skipIfDBFeature(*feature_name_strings) | django.topics.testing.tools#django.test.skipIfDBFeature |
skipUnlessDBFeature(*feature_name_strings) | django.topics.testing.tools#django.test.skipUnlessDBFeature |
class TestCase | django.topics.testing.tools#django.test.TestCase |
TestCase.databases | django.topics.testing.tools#django.test.TestCase.databases |
class TransactionTestCase | django.topics.testing.tools#django.test.TransactionTestCase |
TransactionTestCase.assertNumQueries(num, func, *args, **kwargs)
Asserts that when func is called with *args and **kwargs that num database queries are executed. If a "using" key is present in kwargs it is used as the database alias for which to check the number of queries: self.assertNumQueries(7, using='non_default_db')
If you wish to call a function with a using parameter you can do it by wrapping the call with a lambda to add an extra parameter: self.assertNumQueries(7, lambda: my_function(using=7))
You can also use this as a context manager: with self.assertNumQueries(2):
Person.objects.create(name="Aaron")
Person.objects.create(name="Daniel") | django.topics.testing.tools#django.test.TransactionTestCase.assertNumQueries |
TransactionTestCase.assertQuerysetEqual(qs, values, transform=None, ordered=True, msg=None)
Asserts that a queryset qs matches a particular iterable of values values. If transform is provided, values is compared to a list produced by applying transform to each member of qs. By default, the comparison is also ordering dependent. If qs doesn’t provide an implicit ordering, you can set the ordered parameter to False, which turns the comparison into a collections.Counter comparison. If the order is undefined (if the given qs isn’t ordered and the comparison is against more than one ordered value), a ValueError is raised. Output in case of error can be customized with the msg argument. Changed in Django 3.2: The default value of transform argument was changed to None. New in Django 3.2: Support for direct comparison between querysets was added. Deprecated since version 3.2: If transform is not provided and values is a list of strings, it’s compared to a list produced by applying repr() to each member of qs. This behavior is deprecated and will be removed in Django 4.1. If you need it, explicitly set transform to repr. | django.topics.testing.tools#django.test.TransactionTestCase.assertQuerysetEqual |
TransactionTestCase.available_apps
Warning This attribute is a private API. It may be changed or removed without a deprecation period in the future, for instance to accommodate changes in application loading. It’s used to optimize Django’s own test suite, which contains hundreds of models but no relations between models in different applications. By default, available_apps is set to None. After each test, Django calls flush to reset the database state. This empties all tables and emits the post_migrate signal, which recreates one content type and four permissions for each model. This operation gets expensive proportionally to the number of models. Setting available_apps to a list of applications instructs Django to behave as if only the models from these applications were available. The behavior of TransactionTestCase changes as follows:
post_migrate is fired before each test to create the content types and permissions for each model in available apps, in case they’re missing. After each test, Django empties only tables corresponding to models in available apps. However, at the database level, truncation may cascade to related models in unavailable apps. Furthermore post_migrate isn’t fired; it will be fired by the next TransactionTestCase, after the correct set of applications is selected. Since the database isn’t fully flushed, if a test creates instances of models not included in available_apps, they will leak and they may cause unrelated tests to fail. Be careful with tests that use sessions; the default session engine stores them in the database. Since post_migrate isn’t emitted after flushing the database, its state after a TransactionTestCase isn’t the same as after a TestCase: it’s missing the rows created by listeners to post_migrate. Considering the order in which tests are executed, this isn’t an issue, provided either all TransactionTestCase in a given test suite declare available_apps, or none of them. available_apps is mandatory in Django’s own test suite. | django.topics.testing.advanced#django.test.TransactionTestCase.available_apps |
TransactionTestCase.databases | django.topics.testing.tools#django.test.TransactionTestCase.databases |
TransactionTestCase.fixtures | django.topics.testing.tools#django.test.TransactionTestCase.fixtures |
TransactionTestCase.reset_sequences
Setting reset_sequences = True on a TransactionTestCase will make sure sequences are always reset before the test run: class TestsThatDependsOnPrimaryKeySequences(TransactionTestCase):
reset_sequences = True
def test_animal_pk(self):
lion = Animal.objects.create(name="lion", sound="roar")
# lion.pk is guaranteed to always be 1
self.assertEqual(lion.pk, 1)
Unless you are explicitly testing primary keys sequence numbers, it is recommended that you do not hard code primary key values in tests. Using reset_sequences = True will slow down the test, since the primary key reset is a relatively expensive database operation. | django.topics.testing.advanced#django.test.TransactionTestCase.reset_sequences |
setup_databases(verbosity, interactive, *, time_keeper=None, keepdb=False, debug_sql=False, parallel=0, aliases=None, serialized_aliases=None, **kwargs)
Creates the test databases. Returns a data structure that provides enough detail to undo the changes that have been made. This data will be provided to the teardown_databases() function at the conclusion of testing. The aliases argument determines which DATABASES aliases test databases should be set up for. If it’s not provided, it defaults to all of DATABASES aliases. The serialized_aliases argument determines what subset of aliases test databases should have their state serialized to allow usage of the serialized_rollback feature. If it’s not provided, it defaults to aliases. Changed in Django 3.2: The time_keeper kwarg was added, and all kwargs were made keyword-only. Changed in Django 4.0: The serialized_aliases kwarg was added. | django.topics.testing.advanced#django.test.utils.setup_databases |
setup_test_environment(debug=None)
Performs global pre-test setup, such as installing instrumentation for the template rendering system and setting up the dummy email outbox. If debug isn’t None, the DEBUG setting is updated to its value. | django.topics.testing.advanced#django.test.utils.setup_test_environment |
teardown_databases(old_config, parallel=0, keepdb=False)
Destroys the test databases, restoring pre-test conditions. old_config is a data structure defining the changes in the database configuration that need to be reversed. It’s the return value of the setup_databases() method. | django.topics.testing.advanced#django.test.utils.teardown_databases |
teardown_test_environment()
Performs global post-test teardown, such as removing instrumentation from the template system and restoring normal email services. | django.topics.testing.advanced#django.test.utils.teardown_test_environment |
Translation Overview In order to make a Django project translatable, you have to add a minimal number of hooks to your Python code and templates. These hooks are called translation strings. They tell Django: “This text should be translated into the end user’s language, if a translation for this text is available in that language.” It’s your responsibility to mark translatable strings; the system can only translate strings it knows about. Django then provides utilities to extract the translation strings into a message file. This file is a convenient way for translators to provide the equivalent of the translation strings in the target language. Once the translators have filled in the message file, it must be compiled. This process relies on the GNU gettext toolset. Once this is done, Django takes care of translating web apps on the fly in each available language, according to users’ language preferences. Django’s internationalization hooks are on by default, and that means there’s a bit of i18n-related overhead in certain places of the framework. If you don’t use internationalization, you should take the two seconds to set USE_I18N = False in your settings file. Then Django will make some optimizations so as not to load the internationalization machinery. Note Make sure you’ve activated translation for your project (the fastest way is to check if MIDDLEWARE includes django.middleware.locale.LocaleMiddleware). If you haven’t yet, see How Django discovers language preference. Internationalization: in Python code Standard translation Specify a translation string by using the function gettext(). It’s convention to import this as a shorter alias, _, to save typing. Note Python’s standard library gettext module installs _() into the global namespace, as an alias for gettext(). In Django, we have chosen not to follow this practice, for a couple of reasons: Sometimes, you should use gettext_lazy() as the default translation method for a particular file. Without _() in the global namespace, the developer has to think about which is the most appropriate translation function. The underscore character (_) is used to represent “the previous result” in Python’s interactive shell and doctest tests. Installing a global _() function causes interference. Explicitly importing gettext() as _() avoids this problem. What functions may be aliased as _? Because of how xgettext (used by makemessages) works, only functions that take a single string argument can be imported as _: gettext() gettext_lazy() In this example, the text "Welcome to my site." is marked as a translation string: from django.http import HttpResponse
from django.utils.translation import gettext as _
def my_view(request):
output = _("Welcome to my site.")
return HttpResponse(output)
You could code this without using the alias. This example is identical to the previous one: from django.http import HttpResponse
from django.utils.translation import gettext
def my_view(request):
output = gettext("Welcome to my site.")
return HttpResponse(output)
Translation works on computed values. This example is identical to the previous two: def my_view(request):
words = ['Welcome', 'to', 'my', 'site.']
output = _(' '.join(words))
return HttpResponse(output)
Translation works on variables. Again, here’s an identical example: def my_view(request):
sentence = 'Welcome to my site.'
output = _(sentence)
return HttpResponse(output)
(The caveat with using variables or computed values, as in the previous two examples, is that Django’s translation-string-detecting utility, django-admin makemessages, won’t be able to find these strings. More on makemessages later.) The strings you pass to _() or gettext() can take placeholders, specified with Python’s standard named-string interpolation syntax. Example: def my_view(request, m, d):
output = _('Today is %(month)s %(day)s.') % {'month': m, 'day': d}
return HttpResponse(output)
This technique lets language-specific translations reorder the placeholder text. For example, an English translation may be "Today is November 26.", while a Spanish translation may be "Hoy es 26 de noviembre." – with the month and the day placeholders swapped. For this reason, you should use named-string interpolation (e.g., %(day)s) instead of positional interpolation (e.g., %s or %d) whenever you have more than a single parameter. If you used positional interpolation, translations wouldn’t be able to reorder placeholder text. Since string extraction is done by the xgettext command, only syntaxes supported by gettext are supported by Django. In particular, Python f-strings are not yet supported by xgettext, and JavaScript template strings need gettext 0.21+. Comments for translators If you would like to give translators hints about a translatable string, you can add a comment prefixed with the Translators keyword on the line preceding the string, e.g.: def my_view(request):
# Translators: This message appears on the home page only
output = gettext("Welcome to my site.")
The comment will then appear in the resulting .po file associated with the translatable construct located below it and should also be displayed by most translation tools. Note Just for completeness, this is the corresponding fragment of the resulting .po file: #. Translators: This message appears on the home page only
# path/to/python/file.py:123
msgid "Welcome to my site."
msgstr ""
This also works in templates. See Comments for translators in templates for more details. Marking strings as no-op Use the function django.utils.translation.gettext_noop() to mark a string as a translation string without translating it. The string is later translated from a variable. Use this if you have constant strings that should be stored in the source language because they are exchanged over systems or users – such as strings in a database – but should be translated at the last possible point in time, such as when the string is presented to the user. Pluralization Use the function django.utils.translation.ngettext() to specify pluralized messages. ngettext() takes three arguments: the singular translation string, the plural translation string and the number of objects. This function is useful when you need your Django application to be localizable to languages where the number and complexity of plural forms is greater than the two forms used in English (‘object’ for the singular and ‘objects’ for all the cases where count is different from one, irrespective of its value.) For example: from django.http import HttpResponse
from django.utils.translation import ngettext
def hello_world(request, count):
page = ngettext(
'there is %(count)d object',
'there are %(count)d objects',
count,
) % {
'count': count,
}
return HttpResponse(page)
In this example the number of objects is passed to the translation languages as the count variable. Note that pluralization is complicated and works differently in each language. Comparing count to 1 isn’t always the correct rule. This code looks sophisticated, but will produce incorrect results for some languages: from django.utils.translation import ngettext
from myapp.models import Report
count = Report.objects.count()
if count == 1:
name = Report._meta.verbose_name
else:
name = Report._meta.verbose_name_plural
text = ngettext(
'There is %(count)d %(name)s available.',
'There are %(count)d %(name)s available.',
count,
) % {
'count': count,
'name': name
}
Don’t try to implement your own singular-or-plural logic; it won’t be correct. In a case like this, consider something like the following: text = ngettext(
'There is %(count)d %(name)s object available.',
'There are %(count)d %(name)s objects available.',
count,
) % {
'count': count,
'name': Report._meta.verbose_name,
}
Note When using ngettext(), make sure you use a single name for every extrapolated variable included in the literal. In the examples above, note how we used the name Python variable in both translation strings. This example, besides being incorrect in some languages as noted above, would fail: text = ngettext(
'There is %(count)d %(name)s available.',
'There are %(count)d %(plural_name)s available.',
count,
) % {
'count': Report.objects.count(),
'name': Report._meta.verbose_name,
'plural_name': Report._meta.verbose_name_plural,
}
You would get an error when running django-admin
compilemessages: a format specification for argument 'name', as in 'msgstr[0]', doesn't exist in 'msgid'
Contextual markers Sometimes words have several meanings, such as "May" in English, which refers to a month name and to a verb. To enable translators to translate these words correctly in different contexts, you can use the django.utils.translation.pgettext() function, or the django.utils.translation.npgettext() function if the string needs pluralization. Both take a context string as the first variable. In the resulting .po file, the string will then appear as often as there are different contextual markers for the same string (the context will appear on the msgctxt line), allowing the translator to give a different translation for each of them. For example: from django.utils.translation import pgettext
month = pgettext("month name", "May")
or: from django.db import models
from django.utils.translation import pgettext_lazy
class MyThing(models.Model):
name = models.CharField(help_text=pgettext_lazy(
'help text for MyThing model', 'This is the help text'))
will appear in the .po file as: msgctxt "month name"
msgid "May"
msgstr ""
Contextual markers are also supported by the translate and blocktranslate template tags. Lazy translation Use the lazy versions of translation functions in django.utils.translation (easily recognizable by the lazy suffix in their names) to translate strings lazily – when the value is accessed rather than when they’re called. These functions store a lazy reference to the string – not the actual translation. The translation itself will be done when the string is used in a string context, such as in template rendering. This is essential when calls to these functions are located in code paths that are executed at module load time. This is something that can easily happen when defining models, forms and model forms, because Django implements these such that their fields are actually class-level attributes. For that reason, make sure to use lazy translations in the following cases: Model fields and relationships verbose_name and help_text option values For example, to translate the help text of the name field in the following model, do the following: from django.db import models
from django.utils.translation import gettext_lazy as _
class MyThing(models.Model):
name = models.CharField(help_text=_('This is the help text'))
You can mark names of ForeignKey, ManyToManyField or OneToOneField relationship as translatable by using their verbose_name options: class MyThing(models.Model):
kind = models.ForeignKey(
ThingKind,
on_delete=models.CASCADE,
related_name='kinds',
verbose_name=_('kind'),
)
Just like you would do in verbose_name you should provide a lowercase verbose name text for the relation as Django will automatically titlecase it when required. Model verbose names values It is recommended to always provide explicit verbose_name and verbose_name_plural options rather than relying on the fallback English-centric and somewhat naïve determination of verbose names Django performs by looking at the model’s class name: from django.db import models
from django.utils.translation import gettext_lazy as _
class MyThing(models.Model):
name = models.CharField(_('name'), help_text=_('This is the help text'))
class Meta:
verbose_name = _('my thing')
verbose_name_plural = _('my things')
Model methods description argument to the @display decorator For model methods, you can provide translations to Django and the admin site with the description argument to the display() decorator: from django.contrib import admin
from django.db import models
from django.utils.translation import gettext_lazy as _
class MyThing(models.Model):
kind = models.ForeignKey(
ThingKind,
on_delete=models.CASCADE,
related_name='kinds',
verbose_name=_('kind'),
)
@admin.display(description=_('Is it a mouse?'))
def is_mouse(self):
return self.kind.type == MOUSE_TYPE
Working with lazy translation objects The result of a gettext_lazy() call can be used wherever you would use a string (a str object) in other Django code, but it may not work with arbitrary Python code. For example, the following won’t work because the requests library doesn’t handle gettext_lazy objects: body = gettext_lazy("I \u2764 Django") # (Unicode :heart:)
requests.post('https://example.com/send', data={'body': body})
You can avoid such problems by casting gettext_lazy() objects to text strings before passing them to non-Django code: requests.post('https://example.com/send', data={'body': str(body)})
If you don’t like the long gettext_lazy name, you can alias it as _ (underscore), like so: from django.db import models
from django.utils.translation import gettext_lazy as _
class MyThing(models.Model):
name = models.CharField(help_text=_('This is the help text'))
Using gettext_lazy() and ngettext_lazy() to mark strings in models and utility functions is a common operation. When you’re working with these objects elsewhere in your code, you should ensure that you don’t accidentally convert them to strings, because they should be converted as late as possible (so that the correct locale is in effect). This necessitates the use of the helper function described next. Lazy translations and plural When using lazy translation for a plural string (n[p]gettext_lazy), you generally don’t know the number argument at the time of the string definition. Therefore, you are authorized to pass a key name instead of an integer as the number argument. Then number will be looked up in the dictionary under that key during string interpolation. Here’s example: from django import forms
from django.core.exceptions import ValidationError
from django.utils.translation import ngettext_lazy
class MyForm(forms.Form):
error_message = ngettext_lazy("You only provided %(num)d argument",
"You only provided %(num)d arguments", 'num')
def clean(self):
# ...
if error:
raise ValidationError(self.error_message % {'num': number})
If the string contains exactly one unnamed placeholder, you can interpolate directly with the number argument: class MyForm(forms.Form):
error_message = ngettext_lazy(
"You provided %d argument",
"You provided %d arguments",
)
def clean(self):
# ...
if error:
raise ValidationError(self.error_message % number)
Formatting strings: format_lazy()
Python’s str.format() method will not work when either the format_string or any of the arguments to str.format() contains lazy translation objects. Instead, you can use django.utils.text.format_lazy(), which creates a lazy object that runs the str.format() method only when the result is included in a string. For example: from django.utils.text import format_lazy
from django.utils.translation import gettext_lazy
...
name = gettext_lazy('John Lennon')
instrument = gettext_lazy('guitar')
result = format_lazy('{name}: {instrument}', name=name, instrument=instrument)
In this case, the lazy translations in result will only be converted to strings when result itself is used in a string (usually at template rendering time). Other uses of lazy in delayed translations For any other case where you would like to delay the translation, but have to pass the translatable string as argument to another function, you can wrap this function inside a lazy call yourself. For example: from django.utils.functional import lazy
from django.utils.safestring import mark_safe
from django.utils.translation import gettext_lazy as _
mark_safe_lazy = lazy(mark_safe, str)
And then later: lazy_string = mark_safe_lazy(_("<p>My <strong>string!</strong></p>"))
Localized names of languages
get_language_info()
The get_language_info() function provides detailed information about languages: >>> from django.utils.translation import activate, get_language_info
>>> activate('fr')
>>> li = get_language_info('de')
>>> print(li['name'], li['name_local'], li['name_translated'], li['bidi'])
German Deutsch Allemand False
The name, name_local, and name_translated attributes of the dictionary contain the name of the language in English, in the language itself, and in your current active language respectively. The bidi attribute is True only for bi-directional languages. The source of the language information is the django.conf.locale module. Similar access to this information is available for template code. See below. Internationalization: in template code Translations in Django templates uses two template tags and a slightly different syntax than in Python code. To give your template access to these tags, put {% load i18n %} toward the top of your template. As with all template tags, this tag needs to be loaded in all templates which use translations, even those templates that extend from other templates which have already loaded the i18n tag. Warning Translated strings will not be escaped when rendered in a template. This allows you to include HTML in translations, for example for emphasis, but potentially dangerous characters (e.g. ") will also be rendered unchanged.
translate template tag The {% translate %} template tag translates either a constant string (enclosed in single or double quotes) or variable content: <title>{% translate "This is the title." %}</title>
<title>{% translate myvar %}</title>
If the noop option is present, variable lookup still takes place but the translation is skipped. This is useful when “stubbing out” content that will require translation in the future: <title>{% translate "myvar" noop %}</title>
Internally, inline translations use an gettext() call. In case a template var (myvar above) is passed to the tag, the tag will first resolve such variable to a string at run-time and then look up that string in the message catalogs. It’s not possible to mix a template variable inside a string within {% translate %}. If your translations require strings with variables (placeholders), use {% blocktranslate %} instead. If you’d like to retrieve a translated string without displaying it, you can use the following syntax: {% translate "This is the title" as the_title %}
<title>{{ the_title }}</title>
<meta name="description" content="{{ the_title }}">
In practice you’ll use this to get a string you can use in multiple places in a template or so you can use the output as an argument for other template tags or filters: {% translate "starting point" as start %}
{% translate "end point" as end %}
{% translate "La Grande Boucle" as race %}
<h1>
<a href="/" title="{% blocktranslate %}Back to '{{ race }}' homepage{% endblocktranslate %}">{{ race }}</a>
</h1>
<p>
{% for stage in tour_stages %}
{% cycle start end %}: {{ stage }}{% if forloop.counter|divisibleby:2 %}<br>{% else %}, {% endif %}
{% endfor %}
</p>
{% translate %} also supports contextual markers using the context keyword: {% translate "May" context "month name" %}
blocktranslate template tag Contrarily to the translate tag, the blocktranslate tag allows you to mark complex sentences consisting of literals and variable content for translation by making use of placeholders: {% blocktranslate %}This string will have {{ value }} inside.{% endblocktranslate %}
To translate a template expression – say, accessing object attributes or using template filters – you need to bind the expression to a local variable for use within the translation block. Examples: {% blocktranslate with amount=article.price %}
That will cost $ {{ amount }}.
{% endblocktranslate %}
{% blocktranslate with myvar=value|filter %}
This will have {{ myvar }} inside.
{% endblocktranslate %}
You can use multiple expressions inside a single blocktranslate tag: {% blocktranslate with book_t=book|title author_t=author|title %}
This is {{ book_t }} by {{ author_t }}
{% endblocktranslate %}
Note The previous more verbose format is still supported: {% blocktranslate with book|title as book_t and author|title as author_t %} Other block tags (for example {% for %} or {% if %}) are not allowed inside a blocktranslate tag. If resolving one of the block arguments fails, blocktranslate will fall back to the default language by deactivating the currently active language temporarily with the deactivate_all() function. This tag also provides for pluralization. To use it: Designate and bind a counter value with the name count. This value will be the one used to select the right plural form. Specify both the singular and plural forms separating them with the {% plural %} tag within the {% blocktranslate %} and {% endblocktranslate %} tags. An example: {% blocktranslate count counter=list|length %}
There is only one {{ name }} object.
{% plural %}
There are {{ counter }} {{ name }} objects.
{% endblocktranslate %}
A more complex example: {% blocktranslate with amount=article.price count years=i.length %}
That will cost $ {{ amount }} per year.
{% plural %}
That will cost $ {{ amount }} per {{ years }} years.
{% endblocktranslate %}
When you use both the pluralization feature and bind values to local variables in addition to the counter value, keep in mind that the blocktranslate construct is internally converted to an ngettext call. This means the same notes regarding ngettext variables apply. Reverse URL lookups cannot be carried out within the blocktranslate and should be retrieved (and stored) beforehand: {% url 'path.to.view' arg arg2 as the_url %}
{% blocktranslate %}
This is a URL: {{ the_url }}
{% endblocktranslate %}
If you’d like to retrieve a translated string without displaying it, you can use the following syntax: {% blocktranslate asvar the_title %}The title is {{ title }}.{% endblocktranslate %}
<title>{{ the_title }}</title>
<meta name="description" content="{{ the_title }}">
In practice you’ll use this to get a string you can use in multiple places in a template or so you can use the output as an argument for other template tags or filters. {% blocktranslate %} also supports contextual markers using the context keyword: {% blocktranslate with name=user.username context "greeting" %}Hi {{ name }}{% endblocktranslate %}
Another feature {% blocktranslate %} supports is the trimmed option. This option will remove newline characters from the beginning and the end of the content of the {% blocktranslate %} tag, replace any whitespace at the beginning and end of a line and merge all lines into one using a space character to separate them. This is quite useful for indenting the content of a {% blocktranslate %} tag without having the indentation characters end up in the corresponding entry in the PO file, which makes the translation process easier. For instance, the following {% blocktranslate %} tag: {% blocktranslate trimmed %}
First sentence.
Second paragraph.
{% endblocktranslate %}
will result in the entry "First sentence. Second paragraph." in the PO file, compared to "\n First sentence.\n Second paragraph.\n", if the trimmed option had not been specified. String literals passed to tags and filters You can translate string literals passed as arguments to tags and filters by using the familiar _() syntax: {% some_tag _("Page not found") value|yesno:_("yes,no") %}
In this case, both the tag and the filter will see the translated string, so they don’t need to be aware of translations. Note In this example, the translation infrastructure will be passed the string "yes,no", not the individual strings "yes" and "no". The translated string will need to contain the comma so that the filter parsing code knows how to split up the arguments. For example, a German translator might translate the string "yes,no" as "ja,nein" (keeping the comma intact). Comments for translators in templates Just like with Python code, these notes for translators can be specified using comments, either with the comment tag: {% comment %}Translators: View verb{% endcomment %}
{% translate "View" %}
{% comment %}Translators: Short intro blurb{% endcomment %}
<p>{% blocktranslate %}A multiline translatable
literal.{% endblocktranslate %}</p>
or with the {# … #} one-line comment constructs: {# Translators: Label of a button that triggers search #}
<button type="submit">{% translate "Go" %}</button>
{# Translators: This is a text of the base template #}
{% blocktranslate %}Ambiguous translatable block of text{% endblocktranslate %}
Note Just for completeness, these are the corresponding fragments of the resulting .po file: #. Translators: View verb
# path/to/template/file.html:10
msgid "View"
msgstr ""
#. Translators: Short intro blurb
# path/to/template/file.html:13
msgid ""
"A multiline translatable"
"literal."
msgstr ""
# ...
#. Translators: Label of a button that triggers search
# path/to/template/file.html:100
msgid "Go"
msgstr ""
#. Translators: This is a text of the base template
# path/to/template/file.html:103
msgid "Ambiguous translatable block of text"
msgstr ""
Switching language in templates If you want to select a language within a template, you can use the language template tag: {% load i18n %}
{% get_current_language as LANGUAGE_CODE %}
<!-- Current language: {{ LANGUAGE_CODE }} -->
<p>{% translate "Welcome to our page" %}</p>
{% language 'en' %}
{% get_current_language as LANGUAGE_CODE %}
<!-- Current language: {{ LANGUAGE_CODE }} -->
<p>{% translate "Welcome to our page" %}</p>
{% endlanguage %}
While the first occurrence of “Welcome to our page” uses the current language, the second will always be in English. Other tags These tags also require a {% load i18n %}. get_available_languages {% get_available_languages as LANGUAGES %} returns a list of tuples in which the first element is the language code and the second is the language name (translated into the currently active locale). get_current_language {% get_current_language as LANGUAGE_CODE %} returns the current user’s preferred language as a string. Example: en-us. See How Django discovers language preference. get_current_language_bidi {% get_current_language_bidi as LANGUAGE_BIDI %} returns the current locale’s direction. If True, it’s a right-to-left language, e.g. Hebrew, Arabic. If False it’s a left-to-right language, e.g. English, French, German, etc.
i18n context processor If you enable the django.template.context_processors.i18n context processor, then each RequestContext will have access to LANGUAGES, LANGUAGE_CODE, and LANGUAGE_BIDI as defined above. get_language_info You can also retrieve information about any of the available languages using provided template tags and filters. To get information about a single language, use the {% get_language_info %} tag: {% get_language_info for LANGUAGE_CODE as lang %}
{% get_language_info for "pl" as lang %}
You can then access the information: Language code: {{ lang.code }}<br>
Name of language: {{ lang.name_local }}<br>
Name in English: {{ lang.name }}<br>
Bi-directional: {{ lang.bidi }}
Name in the active language: {{ lang.name_translated }}
get_language_info_list You can also use the {% get_language_info_list %} template tag to retrieve information for a list of languages (e.g. active languages as specified in LANGUAGES). See the section about the set_language redirect view for an example of how to display a language selector using {% get_language_info_list %}. In addition to LANGUAGES style list of tuples, {% get_language_info_list %} supports lists of language codes. If you do this in your view: context = {'available_languages': ['en', 'es', 'fr']}
return render(request, 'mytemplate.html', context)
you can iterate over those languages in the template: {% get_language_info_list for available_languages as langs %}
{% for lang in langs %} ... {% endfor %}
Template filters There are also some filters available for convenience:
{{ LANGUAGE_CODE|language_name }} (“German”)
{{ LANGUAGE_CODE|language_name_local }} (“Deutsch”)
{{ LANGUAGE_CODE|language_bidi }} (False)
{{ LANGUAGE_CODE|language_name_translated }} (“německy”, when active language is Czech) Internationalization: in JavaScript code Adding translations to JavaScript poses some problems: JavaScript code doesn’t have access to a gettext implementation. JavaScript code doesn’t have access to .po or .mo files; they need to be delivered by the server. The translation catalogs for JavaScript should be kept as small as possible. Django provides an integrated solution for these problems: It passes the translations into JavaScript, so you can call gettext, etc., from within JavaScript. The main solution to these problems is the following JavaScriptCatalog view, which generates a JavaScript code library with functions that mimic the gettext interface, plus an array of translation strings. The JavaScriptCatalog view
class JavaScriptCatalog
A view that produces a JavaScript code library with functions that mimic the gettext interface, plus an array of translation strings. Attributes
domain
Translation domain containing strings to add in the view output. Defaults to 'djangojs'.
packages
A list of application names among installed applications. Those apps should contain a locale directory. All those catalogs plus all catalogs found in LOCALE_PATHS (which are always included) are merged into one catalog. Defaults to None, which means that all available translations from all INSTALLED_APPS are provided in the JavaScript output.
Example with default values: from django.views.i18n import JavaScriptCatalog
urlpatterns = [
path('jsi18n/', JavaScriptCatalog.as_view(), name='javascript-catalog'),
]
Example with custom packages: urlpatterns = [
path('jsi18n/myapp/',
JavaScriptCatalog.as_view(packages=['your.app.label']),
name='javascript-catalog'),
]
If your root URLconf uses i18n_patterns(), JavaScriptCatalog must also be wrapped by i18n_patterns() for the catalog to be correctly generated. Example with i18n_patterns(): from django.conf.urls.i18n import i18n_patterns
urlpatterns = i18n_patterns(
path('jsi18n/', JavaScriptCatalog.as_view(), name='javascript-catalog'),
)
The precedence of translations is such that the packages appearing later in the packages argument have higher precedence than the ones appearing at the beginning. This is important in the case of clashing translations for the same literal. If you use more than one JavaScriptCatalog view on a site and some of them define the same strings, the strings in the catalog that was loaded last take precedence. Using the JavaScript translation catalog To use the catalog, pull in the dynamically generated script like this: <script src="{% url 'javascript-catalog' %}"></script>
This uses reverse URL lookup to find the URL of the JavaScript catalog view. When the catalog is loaded, your JavaScript code can use the following methods: gettext ngettext interpolate get_format gettext_noop pgettext npgettext pluralidx gettext The gettext function behaves similarly to the standard gettext interface within your Python code: document.write(gettext('this is to be translated'));
ngettext The ngettext function provides an interface to pluralize words and phrases: const objectCount = 1 // or 0, or 2, or 3, ...
const string = ngettext(
'literal for the singular case',
'literal for the plural case',
objectCount
);
interpolate The interpolate function supports dynamically populating a format string. The interpolation syntax is borrowed from Python, so the interpolate function supports both positional and named interpolation:
Positional interpolation: obj contains a JavaScript Array object whose elements values are then sequentially interpolated in their corresponding fmt placeholders in the same order they appear. For example: const formats = ngettext(
'There is %s object. Remaining: %s',
'There are %s objects. Remaining: %s',
11
);
const string = interpolate(formats, [11, 20]);
// string is 'There are 11 objects. Remaining: 20'
Named interpolation: This mode is selected by passing the optional boolean named parameter as true. obj contains a JavaScript object or associative array. For example: const data = {
count: 10,
total: 50
};
const formats = ngettext(
'Total: %(total)s, there is %(count)s object',
'there are %(count)s of a total of %(total)s objects',
data.count
);
const string = interpolate(formats, data, true);
You shouldn’t go over the top with string interpolation, though: this is still JavaScript, so the code has to make repeated regular-expression substitutions. This isn’t as fast as string interpolation in Python, so keep it to those cases where you really need it (for example, in conjunction with ngettext to produce proper pluralizations). get_format The get_format function has access to the configured i18n formatting settings and can retrieve the format string for a given setting name: document.write(get_format('DATE_FORMAT'));
// 'N j, Y'
It has access to the following settings: DATE_FORMAT DATE_INPUT_FORMATS DATETIME_FORMAT DATETIME_INPUT_FORMATS DECIMAL_SEPARATOR FIRST_DAY_OF_WEEK MONTH_DAY_FORMAT NUMBER_GROUPING SHORT_DATE_FORMAT SHORT_DATETIME_FORMAT THOUSAND_SEPARATOR TIME_FORMAT TIME_INPUT_FORMATS YEAR_MONTH_FORMAT This is useful for maintaining formatting consistency with the Python-rendered values. gettext_noop This emulates the gettext function but does nothing, returning whatever is passed to it: document.write(gettext_noop('this will not be translated'));
This is useful for stubbing out portions of the code that will need translation in the future. pgettext The pgettext function behaves like the Python variant (pgettext()), providing a contextually translated word: document.write(pgettext('month name', 'May'));
npgettext The npgettext function also behaves like the Python variant (npgettext()), providing a pluralized contextually translated word: document.write(npgettext('group', 'party', 1));
// party
document.write(npgettext('group', 'party', 2));
// parties
pluralidx The pluralidx function works in a similar way to the pluralize template filter, determining if a given count should use a plural form of a word or not: document.write(pluralidx(0));
// true
document.write(pluralidx(1));
// false
document.write(pluralidx(2));
// true
In the simplest case, if no custom pluralization is needed, this returns false for the integer 1 and true for all other numbers. However, pluralization is not this simple in all languages. If the language does not support pluralization, an empty value is provided. Additionally, if there are complex rules around pluralization, the catalog view will render a conditional expression. This will evaluate to either a true (should pluralize) or false (should not pluralize) value. The JSONCatalog view
class JSONCatalog
In order to use another client-side library to handle translations, you may want to take advantage of the JSONCatalog view. It’s similar to JavaScriptCatalog but returns a JSON response. See the documentation for JavaScriptCatalog to learn about possible values and use of the domain and packages attributes. The response format is as follows: {
"catalog": {
# Translations catalog
},
"formats": {
# Language formats for date, time, etc.
},
"plural": "..." # Expression for plural forms, or null.
}
Note on performance The various JavaScript/JSON i18n views generate the catalog from .mo files on every request. Since its output is constant, at least for a given version of a site, it’s a good candidate for caching. Server-side caching will reduce CPU load. It’s easily implemented with the cache_page() decorator. To trigger cache invalidation when your translations change, provide a version-dependent key prefix, as shown in the example below, or map the view at a version-dependent URL: from django.views.decorators.cache import cache_page
from django.views.i18n import JavaScriptCatalog
# The value returned by get_version() must change when translations change.
urlpatterns = [
path('jsi18n/',
cache_page(86400, key_prefix='js18n-%s' % get_version())(JavaScriptCatalog.as_view()),
name='javascript-catalog'),
]
Client-side caching will save bandwidth and make your site load faster. If you’re using ETags (ConditionalGetMiddleware), you’re already covered. Otherwise, you can apply conditional decorators. In the following example, the cache is invalidated whenever you restart your application server: from django.utils import timezone
from django.views.decorators.http import last_modified
from django.views.i18n import JavaScriptCatalog
last_modified_date = timezone.now()
urlpatterns = [
path('jsi18n/',
last_modified(lambda req, **kw: last_modified_date)(JavaScriptCatalog.as_view()),
name='javascript-catalog'),
]
You can even pre-generate the JavaScript catalog as part of your deployment procedure and serve it as a static file. This radical technique is implemented in django-statici18n. Internationalization: in URL patterns Django provides two mechanisms to internationalize URL patterns: Adding the language prefix to the root of the URL patterns to make it possible for LocaleMiddleware to detect the language to activate from the requested URL. Making URL patterns themselves translatable via the django.utils.translation.gettext_lazy() function. Warning Using either one of these features requires that an active language be set for each request; in other words, you need to have django.middleware.locale.LocaleMiddleware in your MIDDLEWARE setting. Language prefix in URL patterns
i18n_patterns(*urls, prefix_default_language=True)
This function can be used in a root URLconf and Django will automatically prepend the current active language code to all URL patterns defined within i18n_patterns(). Setting prefix_default_language to False removes the prefix from the default language (LANGUAGE_CODE). This can be useful when adding translations to existing site so that the current URLs won’t change. Example URL patterns: from django.conf.urls.i18n import i18n_patterns
from django.urls import include, path
from about import views as about_views
from news import views as news_views
from sitemap.views import sitemap
urlpatterns = [
path('sitemap.xml', sitemap, name='sitemap-xml'),
]
news_patterns = ([
path('', news_views.index, name='index'),
path('category/<slug:slug>/', news_views.category, name='category'),
path('<slug:slug>/', news_views.details, name='detail'),
], 'news')
urlpatterns += i18n_patterns(
path('about/', about_views.main, name='about'),
path('news/', include(news_patterns, namespace='news')),
)
After defining these URL patterns, Django will automatically add the language prefix to the URL patterns that were added by the i18n_patterns function. Example: >>> from django.urls import reverse
>>> from django.utils.translation import activate
>>> activate('en')
>>> reverse('sitemap-xml')
'/sitemap.xml'
>>> reverse('news:index')
'/en/news/'
>>> activate('nl')
>>> reverse('news:detail', kwargs={'slug': 'news-slug'})
'/nl/news/news-slug/'
With prefix_default_language=False and LANGUAGE_CODE='en', the URLs will be: >>> activate('en')
>>> reverse('news:index')
'/news/'
>>> activate('nl')
>>> reverse('news:index')
'/nl/news/'
Warning i18n_patterns() is only allowed in a root URLconf. Using it within an included URLconf will throw an ImproperlyConfigured exception. Warning Ensure that you don’t have non-prefixed URL patterns that might collide with an automatically-added language prefix. Translating URL patterns URL patterns can also be marked translatable using the gettext_lazy() function. Example: from django.conf.urls.i18n import i18n_patterns
from django.urls import include, path
from django.utils.translation import gettext_lazy as _
from about import views as about_views
from news import views as news_views
from sitemaps.views import sitemap
urlpatterns = [
path('sitemap.xml', sitemap, name='sitemap-xml'),
]
news_patterns = ([
path('', news_views.index, name='index'),
path(_('category/<slug:slug>/'), news_views.category, name='category'),
path('<slug:slug>/', news_views.details, name='detail'),
], 'news')
urlpatterns += i18n_patterns(
path(_('about/'), about_views.main, name='about'),
path(_('news/'), include(news_patterns, namespace='news')),
)
After you’ve created the translations, the reverse() function will return the URL in the active language. Example: >>> from django.urls import reverse
>>> from django.utils.translation import activate
>>> activate('en')
>>> reverse('news:category', kwargs={'slug': 'recent'})
'/en/news/category/recent/'
>>> activate('nl')
>>> reverse('news:category', kwargs={'slug': 'recent'})
'/nl/nieuws/categorie/recent/'
Warning In most cases, it’s best to use translated URLs only within a language code prefixed block of patterns (using i18n_patterns()), to avoid the possibility that a carelessly translated URL causes a collision with a non-translated URL pattern. Reversing in templates If localized URLs get reversed in templates they always use the current language. To link to a URL in another language use the language template tag. It enables the given language in the enclosed template section: {% load i18n %}
{% get_available_languages as languages %}
{% translate "View this category in:" %}
{% for lang_code, lang_name in languages %}
{% language lang_code %}
<a href="{% url 'category' slug=category.slug %}">{{ lang_name }}</a>
{% endlanguage %}
{% endfor %}
The language tag expects the language code as the only argument. Localization: how to create language files Once the string literals of an application have been tagged for later translation, the translation themselves need to be written (or obtained). Here’s how that works. Message files The first step is to create a message file for a new language. A message file is a plain-text file, representing a single language, that contains all available translation strings and how they should be represented in the given language. Message files have a .po file extension. Django comes with a tool, django-admin makemessages, that automates the creation and upkeep of these files. Gettext utilities The makemessages command (and compilemessages discussed later) use commands from the GNU gettext toolset: xgettext, msgfmt, msgmerge and msguniq. The minimum version of the gettext utilities supported is 0.15. To create or update a message file, run this command: django-admin makemessages -l de
…where de is the locale name for the message file you want to create. For example, pt_BR for Brazilian Portuguese, de_AT for Austrian German or id for Indonesian. The script should be run from one of two places: The root directory of your Django project (the one that contains manage.py). The root directory of one of your Django apps. The script runs over your project source tree or your application source tree and pulls out all strings marked for translation (see How Django discovers translations and be sure LOCALE_PATHS is configured correctly). It creates (or updates) a message file in the directory locale/LANG/LC_MESSAGES. In the de example, the file will be locale/de/LC_MESSAGES/django.po. When you run makemessages from the root directory of your project, the extracted strings will be automatically distributed to the proper message files. That is, a string extracted from a file of an app containing a locale directory will go in a message file under that directory. A string extracted from a file of an app without any locale directory will either go in a message file under the directory listed first in LOCALE_PATHS or will generate an error if LOCALE_PATHS is empty. By default django-admin makemessages examines every file that has the .html, .txt or .py file extension. If you want to override that default, use the --extension or -e option to specify the file extensions to examine: django-admin makemessages -l de -e txt
Separate multiple extensions with commas and/or use -e or --extension multiple times: django-admin makemessages -l de -e html,txt -e xml
Warning When creating message files from JavaScript source code you need to use the special djangojs domain, not -e js. Using Jinja2 templates? makemessages doesn’t understand the syntax of Jinja2 templates. To extract strings from a project containing Jinja2 templates, use Message Extracting from Babel instead. Here’s an example babel.cfg configuration file: # Extraction from Python source files
[python: **.py]
# Extraction from Jinja2 templates
[jinja2: **.jinja]
extensions = jinja2.ext.with_
Make sure you list all extensions you’re using! Otherwise Babel won’t recognize the tags defined by these extensions and will ignore Jinja2 templates containing them entirely. Babel provides similar features to makemessages, can replace it in general, and doesn’t depend on gettext. For more information, read its documentation about working with message catalogs. No gettext? If you don’t have the gettext utilities installed, makemessages will create empty files. If that’s the case, either install the gettext utilities or copy the English message file (locale/en/LC_MESSAGES/django.po) if available and use it as a starting point, which is an empty translation file. Working on Windows? If you’re using Windows and need to install the GNU gettext utilities so makemessages works, see gettext on Windows for more information. Each .po file contains a small bit of metadata, such as the translation maintainer’s contact information, but the bulk of the file is a list of messages – mappings between translation strings and the actual translated text for the particular language. For example, if your Django app contained a translation string for the text "Welcome to my site.", like so: _("Welcome to my site.")
…then django-admin makemessages will have created a .po file containing the following snippet – a message: #: path/to/python/module.py:23
msgid "Welcome to my site."
msgstr ""
A quick explanation:
msgid is the translation string, which appears in the source. Don’t change it.
msgstr is where you put the language-specific translation. It starts out empty, so it’s your responsibility to change it. Make sure you keep the quotes around your translation. As a convenience, each message includes, in the form of a comment line prefixed with # and located above the msgid line, the filename and line number from which the translation string was gleaned. Long messages are a special case. There, the first string directly after the msgstr (or msgid) is an empty string. Then the content itself will be written over the next few lines as one string per line. Those strings are directly concatenated. Don’t forget trailing spaces within the strings; otherwise, they’ll be tacked together without whitespace! Mind your charset Due to the way the gettext tools work internally and because we want to allow non-ASCII source strings in Django’s core and your applications, you must use UTF-8 as the encoding for your PO files (the default when PO files are created). This means that everybody will be using the same encoding, which is important when Django processes the PO files. Fuzzy entries makemessages sometimes generates translation entries marked as fuzzy, e.g. when translations are inferred from previously translated strings. By default, fuzzy entries are not processed by compilemessages. To reexamine all source code and templates for new translation strings and update all message files for all languages, run this: django-admin makemessages -a
Compiling message files After you create your message file – and each time you make changes to it – you’ll need to compile it into a more efficient form, for use by gettext. Do this with the django-admin compilemessages utility. This tool runs over all available .po files and creates .mo files, which are binary files optimized for use by gettext. In the same directory from which you ran django-admin makemessages, run django-admin compilemessages like this: django-admin compilemessages
That’s it. Your translations are ready for use. Working on Windows? If you’re using Windows and need to install the GNU gettext utilities so django-admin compilemessages works see gettext on Windows for more information. .po files: Encoding and BOM usage. Django only supports .po files encoded in UTF-8 and without any BOM (Byte Order Mark) so if your text editor adds such marks to the beginning of files by default then you will need to reconfigure it. Troubleshooting: gettext() incorrectly detects python-format in strings with percent signs In some cases, such as strings with a percent sign followed by a space and a string conversion type (e.g. _("10% interest")), gettext() incorrectly flags strings with python-format. If you try to compile message files with incorrectly flagged strings, you’ll get an error message like number of format specifications in 'msgid' and
'msgstr' does not match or 'msgstr' is not a valid Python format string,
unlike 'msgid'. To workaround this, you can escape percent signs by adding a second percent sign: from django.utils.translation import gettext as _
output = _("10%% interest")
Or you can use no-python-format so that all percent signs are treated as literals: # xgettext:no-python-format
output = _("10% interest")
Creating message files from JavaScript source code You create and update the message files the same way as the other Django message files – with the django-admin makemessages tool. The only difference is you need to explicitly specify what in gettext parlance is known as a domain in this case the djangojs domain, by providing a -d
djangojs parameter, like this: django-admin makemessages -d djangojs -l de
This would create or update the message file for JavaScript for German. After updating message files, run django-admin compilemessages the same way as you do with normal Django message files.
gettext on Windows This is only needed for people who either want to extract message IDs or compile message files (.po). Translation work itself involves editing existing files of this type, but if you want to create your own message files, or want to test or compile a changed message file, download a precompiled binary installer. You may also use gettext binaries you have obtained elsewhere, so long as the xgettext --version command works properly. Do not attempt to use Django translation utilities with a gettext package if the command xgettext
--version entered at a Windows command prompt causes a popup window saying “xgettext.exe has generated errors and will be closed by Windows”. Customizing the makemessages command If you want to pass additional parameters to xgettext, you need to create a custom makemessages command and override its xgettext_options attribute: from django.core.management.commands import makemessages
class Command(makemessages.Command):
xgettext_options = makemessages.Command.xgettext_options + ['--keyword=mytrans']
If you need more flexibility, you could also add a new argument to your custom makemessages command: from django.core.management.commands import makemessages
class Command(makemessages.Command):
def add_arguments(self, parser):
super().add_arguments(parser)
parser.add_argument(
'--extra-keyword',
dest='xgettext_keywords',
action='append',
)
def handle(self, *args, **options):
xgettext_keywords = options.pop('xgettext_keywords')
if xgettext_keywords:
self.xgettext_options = (
makemessages.Command.xgettext_options[:] +
['--keyword=%s' % kwd for kwd in xgettext_keywords]
)
super().handle(*args, **options)
Miscellaneous The set_language redirect view
set_language(request)
As a convenience, Django comes with a view, django.views.i18n.set_language(), that sets a user’s language preference and redirects to a given URL or, by default, back to the previous page. Activate this view by adding the following line to your URLconf: path('i18n/', include('django.conf.urls.i18n')),
(Note that this example makes the view available at /i18n/setlang/.) Warning Make sure that you don’t include the above URL within i18n_patterns() - it needs to be language-independent itself to work correctly. The view expects to be called via the POST method, with a language parameter set in request. If session support is enabled, the view saves the language choice in the user’s session. It also saves the language choice in a cookie that is named django_language by default. (The name can be changed through the LANGUAGE_COOKIE_NAME setting.) After setting the language choice, Django looks for a next parameter in the POST or GET data. If that is found and Django considers it to be a safe URL (i.e. it doesn’t point to a different host and uses a safe scheme), a redirect to that URL will be performed. Otherwise, Django may fall back to redirecting the user to the URL from the Referer header or, if it is not set, to /, depending on the nature of the request: If the request accepts HTML content (based on its Accept HTTP header), the fallback will always be performed. If the request doesn’t accept HTML, the fallback will be performed only if the next parameter was set. Otherwise a 204 status code (No Content) will be returned. Here’s example HTML template code: {% load i18n %}
<form action="{% url 'set_language' %}" method="post">{% csrf_token %}
<input name="next" type="hidden" value="{{ redirect_to }}">
<select name="language">
{% get_current_language as LANGUAGE_CODE %}
{% get_available_languages as LANGUAGES %}
{% get_language_info_list for LANGUAGES as languages %}
{% for language in languages %}
<option value="{{ language.code }}"{% if language.code == LANGUAGE_CODE %} selected{% endif %}>
{{ language.name_local }} ({{ language.code }})
</option>
{% endfor %}
</select>
<input type="submit" value="Go">
</form>
In this example, Django looks up the URL of the page to which the user will be redirected in the redirect_to context variable. Explicitly setting the active language You may want to set the active language for the current session explicitly. Perhaps a user’s language preference is retrieved from another system, for example. You’ve already been introduced to django.utils.translation.activate(). That applies to the current thread only. To persist the language for the entire session in a cookie, set the LANGUAGE_COOKIE_NAME cookie on the response: from django.conf import settings
from django.http import HttpResponse
from django.utils import translation
user_language = 'fr'
translation.activate(user_language)
response = HttpResponse(...)
response.set_cookie(settings.LANGUAGE_COOKIE_NAME, user_language)
You would typically want to use both: django.utils.translation.activate() changes the language for this thread, and setting the cookie makes this preference persist in future requests. Using translations outside views and templates While Django provides a rich set of i18n tools for use in views and templates, it does not restrict the usage to Django-specific code. The Django translation mechanisms can be used to translate arbitrary texts to any language that is supported by Django (as long as an appropriate translation catalog exists, of course). You can load a translation catalog, activate it and translate text to language of your choice, but remember to switch back to original language, as activating a translation catalog is done on per-thread basis and such change will affect code running in the same thread. For example: from django.utils import translation
def welcome_translated(language):
cur_language = translation.get_language()
try:
translation.activate(language)
text = translation.gettext('welcome')
finally:
translation.activate(cur_language)
return text
Calling this function with the value 'de' will give you "Willkommen", regardless of LANGUAGE_CODE and language set by middleware. Functions of particular interest are django.utils.translation.get_language() which returns the language used in the current thread, django.utils.translation.activate() which activates a translation catalog for the current thread, and django.utils.translation.check_for_language() which checks if the given language is supported by Django. To help write more concise code, there is also a context manager django.utils.translation.override() that stores the current language on enter and restores it on exit. With it, the above example becomes: from django.utils import translation
def welcome_translated(language):
with translation.override(language):
return translation.gettext('welcome')
Language cookie A number of settings can be used to adjust language cookie options: LANGUAGE_COOKIE_NAME LANGUAGE_COOKIE_AGE LANGUAGE_COOKIE_DOMAIN LANGUAGE_COOKIE_HTTPONLY LANGUAGE_COOKIE_PATH LANGUAGE_COOKIE_SAMESITE LANGUAGE_COOKIE_SECURE Implementation notes Specialties of Django translation Django’s translation machinery uses the standard gettext module that comes with Python. If you know gettext, you might note these specialties in the way Django does translation: The string domain is django or djangojs. This string domain is used to differentiate between different programs that store their data in a common message-file library (usually /usr/share/locale/). The django domain is used for Python and template translation strings and is loaded into the global translation catalogs. The djangojs domain is only used for JavaScript translation catalogs to make sure that those are as small as possible. Django doesn’t use xgettext alone. It uses Python wrappers around xgettext and msgfmt. This is mostly for convenience. How Django discovers language preference Once you’ve prepared your translations – or, if you want to use the translations that come with Django – you’ll need to activate translation for your app. Behind the scenes, Django has a very flexible model of deciding which language should be used – installation-wide, for a particular user, or both. To set an installation-wide language preference, set LANGUAGE_CODE. Django uses this language as the default translation – the final attempt if no better matching translation is found through one of the methods employed by the locale middleware (see below). If all you want is to run Django with your native language all you need to do is set LANGUAGE_CODE and make sure the corresponding message files and their compiled versions (.mo) exist. If you want to let each individual user specify which language they prefer, then you also need to use the LocaleMiddleware. LocaleMiddleware enables language selection based on data from the request. It customizes content for each user. To use LocaleMiddleware, add 'django.middleware.locale.LocaleMiddleware' to your MIDDLEWARE setting. Because middleware order matters, follow these guidelines: Make sure it’s one of the first middleware installed. It should come after SessionMiddleware, because LocaleMiddleware makes use of session data. And it should come before CommonMiddleware because CommonMiddleware needs an activated language in order to resolve the requested URL. If you use CacheMiddleware, put LocaleMiddleware after it. For example, your MIDDLEWARE might look like this: MIDDLEWARE = [
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.locale.LocaleMiddleware',
'django.middleware.common.CommonMiddleware',
]
(For more on middleware, see the middleware documentation.) LocaleMiddleware tries to determine the user’s language preference by following this algorithm: First, it looks for the language prefix in the requested URL. This is only performed when you are using the i18n_patterns function in your root URLconf. See Internationalization: in URL patterns for more information about the language prefix and how to internationalize URL patterns.
Failing that, it looks for a cookie. The name of the cookie used is set by the LANGUAGE_COOKIE_NAME setting. (The default name is django_language.) Failing that, it looks at the Accept-Language HTTP header. This header is sent by your browser and tells the server which language(s) you prefer, in order by priority. Django tries each language in the header until it finds one with available translations. Failing that, it uses the global LANGUAGE_CODE setting. Notes: In each of these places, the language preference is expected to be in the standard language format, as a string. For example, Brazilian Portuguese is pt-br. If a base language is available but the sublanguage specified is not, Django uses the base language. For example, if a user specifies de-at (Austrian German) but Django only has de available, Django uses de.
Only languages listed in the LANGUAGES setting can be selected. If you want to restrict the language selection to a subset of provided languages (because your application doesn’t provide all those languages), set LANGUAGES to a list of languages. For example: LANGUAGES = [
('de', _('German')),
('en', _('English')),
]
This example restricts languages that are available for automatic selection to German and English (and any sublanguage, like de-ch or en-us).
If you define a custom LANGUAGES setting, as explained in the previous bullet, you can mark the language names as translation strings – but use gettext_lazy() instead of gettext() to avoid a circular import. Here’s a sample settings file: from django.utils.translation import gettext_lazy as _
LANGUAGES = [
('de', _('German')),
('en', _('English')),
]
Once LocaleMiddleware determines the user’s preference, it makes this preference available as request.LANGUAGE_CODE for each HttpRequest. Feel free to read this value in your view code. Here’s an example: from django.http import HttpResponse
def hello_world(request, count):
if request.LANGUAGE_CODE == 'de-at':
return HttpResponse("You prefer to read Austrian German.")
else:
return HttpResponse("You prefer to read another language.")
Note that, with static (middleware-less) translation, the language is in settings.LANGUAGE_CODE, while with dynamic (middleware) translation, it’s in request.LANGUAGE_CODE. How Django discovers translations At runtime, Django builds an in-memory unified catalog of literals-translations. To achieve this it looks for translations by following this algorithm regarding the order in which it examines the different file paths to load the compiled message files (.mo) and the precedence of multiple translations for the same literal: The directories listed in LOCALE_PATHS have the highest precedence, with the ones appearing first having higher precedence than the ones appearing later. Then, it looks for and uses if it exists a locale directory in each of the installed apps listed in INSTALLED_APPS. The ones appearing first have higher precedence than the ones appearing later. Finally, the Django-provided base translation in django/conf/locale is used as a fallback. See also The translations for literals included in JavaScript assets are looked up following a similar but not identical algorithm. See JavaScriptCatalog for more details. You can also put custom format files in the LOCALE_PATHS directories if you also set FORMAT_MODULE_PATH. In all cases the name of the directory containing the translation is expected to be named using locale name notation. E.g. de, pt_BR, es_AR, etc. Untranslated strings for territorial language variants use the translations of the generic language. For example, untranslated pt_BR strings use pt translations. This way, you can write applications that include their own translations, and you can override base translations in your project. Or, you can build a big project out of several apps and put all translations into one big common message file specific to the project you are composing. The choice is yours. All message file repositories are structured the same way. They are: All paths listed in LOCALE_PATHS in your settings file are searched for <language>/LC_MESSAGES/django.(po|mo)
$APPPATH/locale/<language>/LC_MESSAGES/django.(po|mo) $PYTHONPATH/django/conf/locale/<language>/LC_MESSAGES/django.(po|mo) To create message files, you use the django-admin makemessages tool. And you use django-admin compilemessages to produce the binary .mo files that are used by gettext. You can also run django-admin compilemessages
--settings=path.to.settings to make the compiler process all the directories in your LOCALE_PATHS setting. Using a non-English base language Django makes the general assumption that the original strings in a translatable project are written in English. You can choose another language, but you must be aware of certain limitations:
gettext only provides two plural forms for the original messages, so you will also need to provide a translation for the base language to include all plural forms if the plural rules for the base language are different from English. When an English variant is activated and English strings are missing, the fallback language will not be the LANGUAGE_CODE of the project, but the original strings. For example, an English user visiting a site with LANGUAGE_CODE set to Spanish and original strings written in Russian will see Russian text rather than Spanish. | django.topics.i18n.translation |
get_script_prefix() | django.ref.urlresolvers#django.urls.get_script_prefix |
include(module, namespace=None)
include(pattern_list)
include((pattern_list, app_namespace), namespace=None)
A function that takes a full Python import path to another URLconf module that should be “included” in this place. Optionally, the application namespace and instance namespace where the entries will be included into can also be specified. Usually, the application namespace should be specified by the included module. If an application namespace is set, the namespace argument can be used to set a different instance namespace. include() also accepts as an argument either an iterable that returns URL patterns or a 2-tuple containing such iterable plus the names of the application namespaces.
Parameters:
module – URLconf module (or module name)
namespace (str) – Instance namespace for the URL entries being included
pattern_list – Iterable of path() and/or re_path() instances.
app_namespace (str) – Application namespace for the URL entries being included | django.ref.urls#django.urls.include |
path(route, view, kwargs=None, name=None) | django.ref.urls#django.urls.path |
re_path(route, view, kwargs=None, name=None) | django.ref.urls#django.urls.re_path |
register_converter(converter, type_name) | django.ref.urls#django.urls.register_converter |
resolve(path, urlconf=None) | django.ref.urlresolvers#django.urls.resolve |
class ResolverMatch
func
The view function that would be used to serve the URL
args
The arguments that would be passed to the view function, as parsed from the URL.
kwargs
The keyword arguments that would be passed to the view function, as parsed from the URL.
url_name
The name of the URL pattern that matches the URL.
route
The route of the matching URL pattern. For example, if path('users/<id>/', ...) is the matching pattern, route will contain 'users/<id>/'.
tried
New in Django 3.2. The list of URL patterns tried before the URL either matched one or exhausted available patterns.
app_name
The application namespace for the URL pattern that matches the URL.
app_names
The list of individual namespace components in the full application namespace for the URL pattern that matches the URL. For example, if the app_name is 'foo:bar', then app_names will be ['foo', 'bar'].
namespace
The instance namespace for the URL pattern that matches the URL.
namespaces
The list of individual namespace components in the full instance namespace for the URL pattern that matches the URL. i.e., if the namespace is foo:bar, then namespaces will be ['foo', 'bar'].
view_name
The name of the view that matches the URL, including the namespace if there is one. | django.ref.urlresolvers#django.urls.ResolverMatch |
app_name
The application namespace for the URL pattern that matches the URL. | django.ref.urlresolvers#django.urls.ResolverMatch.app_name |
app_names
The list of individual namespace components in the full application namespace for the URL pattern that matches the URL. For example, if the app_name is 'foo:bar', then app_names will be ['foo', 'bar']. | django.ref.urlresolvers#django.urls.ResolverMatch.app_names |
args
The arguments that would be passed to the view function, as parsed from the URL. | django.ref.urlresolvers#django.urls.ResolverMatch.args |
func
The view function that would be used to serve the URL | django.ref.urlresolvers#django.urls.ResolverMatch.func |
kwargs
The keyword arguments that would be passed to the view function, as parsed from the URL. | django.ref.urlresolvers#django.urls.ResolverMatch.kwargs |
namespace
The instance namespace for the URL pattern that matches the URL. | django.ref.urlresolvers#django.urls.ResolverMatch.namespace |
namespaces
The list of individual namespace components in the full instance namespace for the URL pattern that matches the URL. i.e., if the namespace is foo:bar, then namespaces will be ['foo', 'bar']. | django.ref.urlresolvers#django.urls.ResolverMatch.namespaces |
route
The route of the matching URL pattern. For example, if path('users/<id>/', ...) is the matching pattern, route will contain 'users/<id>/'. | django.ref.urlresolvers#django.urls.ResolverMatch.route |
tried
New in Django 3.2. The list of URL patterns tried before the URL either matched one or exhausted available patterns. | django.ref.urlresolvers#django.urls.ResolverMatch.tried |
url_name
The name of the URL pattern that matches the URL. | django.ref.urlresolvers#django.urls.ResolverMatch.url_name |
view_name
The name of the view that matches the URL, including the namespace if there is one. | django.ref.urlresolvers#django.urls.ResolverMatch.view_name |
reverse(viewname, urlconf=None, args=None, kwargs=None, current_app=None) | django.ref.urlresolvers#django.urls.reverse |
reverse_lazy(viewname, urlconf=None, args=None, kwargs=None, current_app=None) | django.ref.urlresolvers#django.urls.reverse_lazy |
add_never_cache_headers(response)
Adds a Cache-Control: max-age=0, no-cache, no-store, must-revalidate,
private header to a response to indicate that a page should never be cached. | django.ref.utils#django.utils.cache.add_never_cache_headers |
get_cache_key(request, key_prefix=None, method='GET', cache=None)
Returns a cache key based on the request path. It can be used in the request phase because it pulls the list of headers to take into account from the global path registry and uses those to build a cache key to check against. If there is no headerlist stored, the page needs to be rebuilt, so this function returns None. | django.ref.utils#django.utils.cache.get_cache_key |
get_max_age(response)
Returns the max-age from the response Cache-Control header as an integer (or None if it wasn’t found or wasn’t an integer). | django.ref.utils#django.utils.cache.get_max_age |
Subsets and Splits