Move to python-magic for alpine compatibility

python-magic is supporting Alpine Linux since 0.4.24 (hence the minimum
version) while file-magic is still not supporting it.

Author: benoit74

pyproject.toml

@@ -13,7 +13,7 @@ dependencies = [
   "colorthief==0.2.1",
   "python-resize-image>=1.1.19,<1.2",
   "Babel>=2.9,<3.0",
-  "file-magic>=0.4.0,<0.5",
+  "python-magic>=0.4.24,<0.5",
   "libzim>=3.4.0,<4.0",
   "beautifulsoup4>=4.9.3,<4.10", # upgrade to 4.10 and later to be done
   "lxml>=4.6.3,<4.10", # upgrade to 4.10 and later to be done

src/zimscraperlib/filesystem.py

@@ -31,7 +31,11 @@ def get_content_mimetype(content: bytes) -> str:
     """MIME Type of content retrieved from magic headers"""
 
     try:
-        detected_mime = magic.detect_from_content(content).mime_type
+        detected_mime = magic.from_buffer(content, mime=True)
+        if isinstance(
+            detected_mime, bytes
+        ):  # pragma: no cover (old python-magic versions where returning bytes)
+            detected_mime = detected_mime.decode()
     except UnicodeDecodeError:
         return "application/octet-stream"
     return MIME_OVERRIDES.get(detected_mime, detected_mime)

tests/filesystem/test_filesystem.py

@@ -28,10 +28,10 @@ def test_content_mimetype_fallback(monkeypatch, undecodable_byte_stream):
     assert get_content_mimetype(undecodable_byte_stream) == "application/octet-stream"
 
     # mock then so we keep coverage on systems where magic works
-    def raising_magic(*args):  # noqa: ARG001
+    def raising_magic(*args, **kwargs):  # noqa: ARG001
         raise UnicodeDecodeError("nocodec", b"", 0, 1, "noreason")
 
-    monkeypatch.setattr(magic, "detect_from_content", raising_magic)
+    monkeypatch.setattr(magic, "from_buffer", raising_magic)
     assert get_content_mimetype(undecodable_byte_stream) == "application/octet-stream"