Python: fix(contents): accept RFC 6838 media types and parameters in data URIs

python/semantic_kernel/contents/utils/data_uri.py

@@ -135,7 +135,16 @@ def from_data_uri(cls: type[_T], data_uri: str | Url, default_mime_type: str = "
         if not data or "," not in data:
             raise ContentInitializationError("Invalid data uri format. The data is missing.")
 
-        pattern = "(((?P<mime_type>[a-zA-Z]+/[a-zA-Z-]+)(?P<parameters>(;[a-zA-Z0-9]+=+[a-zA-Z0-9]+)*))?(;+(?P<data_format>.*)))?(,(?P<data_str>.*))"  # noqa: E501
+        # Parameters use the RFC 2045 token alphabet, which is broader than a
+        # media type's restricted-name alphabet. RFC 2397 allows parameters even
+        # when the default text/plain media type is omitted.
+        parameter_token = r"[a-zA-Z0-9!#$%&'*+.^_`|~-]+"
+        pattern = (
+            r"(?P<mime_type>[a-zA-Z0-9!#$&^_.+-]+/[a-zA-Z0-9!#$&^_.+-]+)?"
+            rf"(?P<parameters>(;{parameter_token}={parameter_token})*)"
+            r"(;+(?P<data_format>[a-zA-Z0-9!#$&^_.+-]*))?"
+            r"(,(?P<data_str>.*))"
+        )
         match = re.match(pattern, data)
         if not match:
             raise ContentInitializationError("Invalid data uri format.")

python/tests/unit/contents/test_data_uri.py

@@ -66,6 +66,33 @@
             "base64",
             id="with_params",
         ),
+        pytest.param(
+            "data:image/svg+xml;base64,PHN2Zy8+",
+            b"<svg/>",
+            "PHN2Zy8+",
+            "image/svg+xml",
+            {},
+            "base64",
+            id="mime_type_with_plus",
+        ),
+        pytest.param(
+            "data:text/plain;charset=utf-8;base64,SGVsbG8=",
+            b"Hello",
+            "SGVsbG8=",
+            "text/plain",
+            {"charset": "utf-8"},
+            "base64",
+            id="parameter_before_data_format",
+        ),
+        pytest.param(
+            "data:application/vnd.ms-excel;base64,AAAA",
+            b"\x00\x00\x00",
+            "AAAA",
+            "application/vnd.ms-excel",
+            {},
+            "base64",
+            id="vendor_mime_type",
+        ),
     ],
 )
 def test_data_uri_from_data_uri_str(
@@ -310,3 +337,20 @@ def test_array():
 def test__data_str(data_bytes, data_str, data_array, data_format, expected_output):
     data_uri = DataUri(data_bytes=data_bytes, data_str=data_str, data_array=data_array, data_format=data_format)
     assert data_uri._data_str() == expected_output
+
+
+@pytest.mark.parametrize("media_type", ["text/plain", ""])
+@pytest.mark.parametrize("encoding,payload", [("", "Hello"), (";base64", "SGVsbG8=")])
+def test_data_uri_parameter_without_required_media_type(media_type, encoding, payload):
+    result = DataUri.from_data_uri(f"data:{media_type};charset=utf-8{encoding},{payload}")
+    assert result.data_bytes == b"Hello"
+    assert result.mime_type == "text/plain"
+    assert result.parameters == {"charset": "utf-8"}
+    assert result.data_format == ("base64" if encoding else None)
+
+
+@pytest.mark.parametrize("value", ["foo*bar", "foo'bar", "foo~bar", "foo%20bar", "foo%3Bbar"])
+def test_data_uri_parameter_uses_parameter_token_alphabet(value):
+    result = DataUri.from_data_uri(f"data:text/plain;name={value},Hello")
+    assert result.data_bytes == b"Hello"
+    assert result.parameters == {"name": value}

python/tests/unit/contents/test_image_content.py

@@ -38,6 +38,12 @@ def test_create_data():
     assert image.data == b"test_data"
 
 
+def test_create_svg_data_uri():
+    image = ImageContent(data_uri="data:image/svg+xml;base64,PHN2Zy8+")
+    assert image.mime_type == "image/svg+xml"
+    assert image.data == b"<svg/>"
+
+
 def test_to_str_uri():
     image = ImageContent(uri="http://test_uri")
     assert str(image) == "http://test_uri/"