refactor: apply review suggestions for clarity and DRY

Author: cchinchilla-dev

src/a2a/client/transports/grpc.py

@@ -64,10 +64,9 @@ def _get_grpc_metadata(
         extensions: list[str] | None = None,
     ) -> list[tuple[str, str]] | None:
         """Creates gRPC metadata for extensions."""
-        if extensions is not None:
-            return [(HTTP_EXTENSION_HEADER.lower(), ','.join(extensions))]
-        if self.extensions is not None:
-            return [(HTTP_EXTENSION_HEADER.lower(), ','.join(self.extensions))]
+        ext_to_use = extensions if extensions is not None else self.extensions
+        if ext_to_use is not None:
+            return [(HTTP_EXTENSION_HEADER.lower(), ','.join(ext_to_use))]
         return None
 
     @classmethod

src/a2a/server/request_handlers/grpc_handler.py

@@ -55,10 +55,10 @@ def _get_metadata_value(
 ) -> list[str]:
     md = context.invocation_metadata
     raw_values: list[str | bytes] = []
+    lower_key = key.lower()
     if isinstance(md, Metadata):
-        raw_values = md.get_all(key.lower())
+        raw_values = md.get_all(lower_key)
     elif isinstance(md, Sequence):
-        lower_key = key.lower()
         raw_values = [e for (k, e) in md if k.lower() == lower_key]
     return [e if isinstance(e, str) else e.decode('utf-8') for e in raw_values]
 

tests/client/transports/test_grpc_client.py

@@ -548,7 +548,7 @@ def test_get_grpc_metadata(
     'test_extensions',
     [
         (['ext1']),  # Test with explicit extensions
-        (None),      # Test with transport's default extensions
+        (None),  # Test with transport's default extensions
     ],
 )
 def test_get_grpc_metadata_uses_lowercase_header_key(