Create image.py

image.py

@@ -0,0 +1,66 @@
+# app/image.py
+
+import re
+from io import BytesIO
+import base64
+from typing import Union
+
+from .typing import ImageType
+
+try:
+    from PIL import Image
+except ImportError:
+    Image = None  # Handle absence of PIL
+
+from .errors import MissingRequirementsError
+
+ALLOWED_EXTENSIONS = {'png', 'jpg', 'jpeg', 'gif', 'webp', 'svg'}
+
+def is_allowed_extension(filename: str) -> bool:
+    """
+    Checks if the given filename has an allowed extension.
+    """
+    return '.' in filename and \
+           filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS
+
+def is_data_uri_an_image(data_uri: str) -> bool:
+    """
+    Checks if the given data URI represents an image.
+    """
+    if not re.match(r'data:image/(\w+);base64,', data_uri):
+        raise ValueError("Invalid data URI image.")
+    image_format = re.match(r'data:image/(\w+);base64,', data_uri).group(1).lower()
+    if image_format not in ALLOWED_EXTENSIONS and image_format != "svg+xml":
+        raise ValueError("Invalid image format (from MIME type).")
+    return True
+
+def extract_data_uri(data_uri: str) -> bytes:
+    """
+    Extracts the binary data from the given data URI.
+    """
+    data = data_uri.split(",")[1]
+    return base64.b64decode(data)
+
+def to_data_uri(image: str) -> str:
+    """
+    Validates and returns the data URI for an image.
+    """
+    is_data_uri_an_image(image)
+    return image
+
+def to_image(image: str) -> ImageType:
+    """
+    Converts a base64-encoded image to bytes.
+    """
+    if Image is None:
+        raise MissingRequirementsError('Install "pillow" package for image processing.')
+    is_data_uri_an_image(image)
+    return extract_data_uri(image)
+
+class MissingRequirementsError(Exception):
+    pass
+
+class ImageResponse:
+    def __init__(self, url: str, alt: str):
+        self.url = url
+        self.alt = alt