[pytx] Implement FileContent class

python-threatexchange/threatexchange/content_type/file_content.py

@@ -0,0 +1,31 @@
+import typing as t
+from content_base import ContentType
+from photo import PhotoContent
+from video import VideoContent
+from PIL import Image
+
+
+class FileContent(ContentType):
+    """
+    ContentType representing a generic file.
+
+    Determines if a file is a photo or video based on file extension.
+    """
+
+    VALID_PHOTO_EXTENSIONS = {ext.lower() for ext in Image.registered_extensions()}
+    VALID_VIDEO_EXTENSIONS = {".mp4", ".avi", ".mov", ".mkv"}
+
+    @classmethod
+    def get_content_type_from_filename(cls, file_name: str) -> t.Type[ContentType]:
+        """
+        Determines content type based on file extension.
+        """
+        file_extension = file_name.lower().rsplit(".", 1)[-1]
+        file_extension = f".{file_extension}"
+
+        if file_extension in cls.VALID_PHOTO_EXTENSIONS:
+            return PhotoContent
+        elif file_extension in cls.VALID_VIDEO_EXTENSIONS:
+            return VideoContent
+        else:
+            return None

python-threatexchange/threatexchange/content_type/tests/test_file_content_type.py

@@ -0,0 +1,25 @@
+import pytest
+from threatexchange.content_type.photo import PhotoContent
+from threatexchange.content_type.video import VideoContent
+from threatexchange.content_type.file_content import FileContent
+
+
+@pytest.mark.parametrize(
+    "file_name,expected_content_type",
+    [
+        ("file.jpg", PhotoContent),
+        ("file.JPG", PhotoContent),
+        ("file.mp4", VideoContent),
+        ("file.MP4", VideoContent),
+        ("archive.photo.png", PhotoContent),
+        ("movie.backup.mp4", VideoContent),
+        ("file.txt", None),
+    ],
+)
+def test_file_content_detection(file_name, expected_content_type):
+    """
+    Tests that FileContent correctly identifies the content type
+    as either PhotoContent or VideoContent based on file extension.
+    """
+    content_type = FileContent.get_content_type_from_filename(file_name)
+    assert content_type == expected_content_type