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"""Process URI templates per http://tools.ietf.org/html/rfc6570.""" |
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from __future__ import annotations |
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import re |
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from typing import TYPE_CHECKING |
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from .expansions import (CommaExpansion, Expansion, |
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FormStyleQueryContinuation, FormStyleQueryExpansion, |
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FragmentExpansion, LabelExpansion, Literal, |
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PathExpansion, PathStyleExpansion, |
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ReservedCommaExpansion, ReservedExpansion, SimpleExpansion) |
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if (TYPE_CHECKING): |
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from collections.abc import Iterable |
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from .variable import Variable |
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class ExpansionReservedError(Exception): |
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"""Exception thrown for reserved but unsupported expansions.""" |
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expansion: str |
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def __init__(self, expansion: str) -> None: |
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self.expansion = expansion |
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def __str__(self) -> str: |
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"""Convert to string.""" |
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return 'Unsupported expansion: ' + self.expansion |
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class ExpansionInvalidError(Exception): |
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"""Exception thrown for unknown expansions.""" |
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expansion: str |
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def __init__(self, expansion: str) -> None: |
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self.expansion = expansion |
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def __str__(self) -> str: |
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"""Convert to string.""" |
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return 'Bad expansion: ' + self.expansion |
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class URITemplate: |
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""" |
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URI Template object. |
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Constructor may raise ExpansionReservedError, ExpansionInvalidError, or VariableInvalidError. |
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""" |
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expansions: list[Expansion] |
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def __init__(self, template: str) -> None: |
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self.expansions = [] |
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parts = re.split(r'(\{[^\}]*\})', template) |
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for part in parts: |
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if (part): |
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if (('{' == part[0]) and ('}' == part[-1])): |
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expansion = part[1:-1] |
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if (re.match('^([a-zA-Z0-9_]|%[0-9a-fA-F][0-9a-fA-F]).*$', expansion)): |
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self.expansions.append(SimpleExpansion(expansion)) |
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elif ('+' == part[1]): |
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self.expansions.append(ReservedExpansion(expansion)) |
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elif ('#' == part[1]): |
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self.expansions.append(FragmentExpansion(expansion)) |
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elif ('.' == part[1]): |
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self.expansions.append(LabelExpansion(expansion)) |
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elif ('/' == part[1]): |
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self.expansions.append(PathExpansion(expansion)) |
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elif (';' == part[1]): |
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self.expansions.append(PathStyleExpansion(expansion)) |
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elif ('?' == part[1]): |
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self.expansions.append(FormStyleQueryExpansion(expansion)) |
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elif ('&' == part[1]): |
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self.expansions.append(FormStyleQueryContinuation(expansion)) |
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elif (',' == part[1]): |
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if ((1 < len(part)) and ('+' == part[2])): |
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self.expansions.append(ReservedCommaExpansion(expansion)) |
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else: |
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self.expansions.append(CommaExpansion(expansion)) |
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elif (part[1] in '=!@|'): |
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raise ExpansionReservedError(part) |
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else: |
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raise ExpansionInvalidError(part) |
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else: |
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if (('{' not in part) and ('}' not in part)): |
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self.expansions.append(Literal(part)) |
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else: |
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raise ExpansionInvalidError(part) |
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@property |
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def variables(self) -> Iterable[Variable]: |
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"""Get all variables in template.""" |
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vars: dict[str, Variable] = {} |
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for expansion in self.expansions: |
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for var in expansion.variables: |
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vars[var.name] = var |
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return vars.values() |
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@property |
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def variable_names(self) -> Iterable[str]: |
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"""Get names of all variables in template.""" |
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vars: dict[str, Variable] = {} |
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for expansion in self.expansions: |
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for var in expansion.variables: |
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vars[var.name] = var |
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return [var.name for var in vars.values()] |
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def expand(self, **kwargs) -> str: |
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""" |
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Expand the template. |
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May raise ExpansionFailed if a composite value is passed to a variable with a prefix modifier. |
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""" |
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expanded = [expansion.expand(kwargs) for expansion in self.expansions] |
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return ''.join([expansion for expansion in expanded if (expansion is not None)]) |
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def partial(self, **kwargs) -> URITemplate: |
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""" |
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Expand the template, preserving expansions for missing variables. |
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May raise ExpansionFailed if a composite value is passed to a variable with a prefix modifier. |
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""" |
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expanded = [expansion.partial(kwargs) for expansion in self.expansions] |
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return URITemplate(''.join(expanded)) |
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@property |
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def expanded(self) -> bool: |
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"""Determine if template is fully expanded.""" |
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return (str(self) == self.expand()) |
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def __str__(self) -> str: |
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"""Convert to string, returns original template.""" |
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return ''.join([str(expansion) for expansion in self.expansions]) |
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def __repr__(self) -> str: |
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"""Convert to string, returns original template.""" |
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return str(self) |
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