Fix the issue of get Authorization header fails during bearer auth (#637)

Co-authored-by: yangben <yangben@zhihu.com>

tests/server/auth/middleware/test_bearer_auth.py

@@ -7,6 +7,7 @@ from typing import Any, cast
 
 import pytest
 from starlette.authentication import AuthCredentials
+from starlette.datastructures import Headers
 from starlette.exceptions import HTTPException
 from starlette.requests import Request
 from starlette.types import Message, Receive, Scope, Send
@@ -221,6 +222,66 @@ class TestBearerAuthBackend:
         assert user.access_token == no_expiry_access_token
         assert user.scopes == ["read", "write"]
 
+    async def test_lowercase_bearer_prefix(
+        self,
+        mock_oauth_provider: OAuthAuthorizationServerProvider[Any, Any, Any],
+        valid_access_token: AccessToken,
+    ):
+        """Test with lowercase 'bearer' prefix in Authorization header"""
+        backend = BearerAuthBackend(provider=mock_oauth_provider)
+        add_token_to_provider(mock_oauth_provider, "valid_token", valid_access_token)
+        headers = Headers({"Authorization": "bearer valid_token"})
+        scope = {"type": "http", "headers": headers.raw}
+        request = Request(scope)
+        result = await backend.authenticate(request)
+        assert result is not None
+        credentials, user = result
+        assert isinstance(credentials, AuthCredentials)
+        assert isinstance(user, AuthenticatedUser)
+        assert credentials.scopes == ["read", "write"]
+        assert user.display_name == "test_client"
+        assert user.access_token == valid_access_token
+
+    async def test_mixed_case_bearer_prefix(
+        self,
+        mock_oauth_provider: OAuthAuthorizationServerProvider[Any, Any, Any],
+        valid_access_token: AccessToken,
+    ):
+        """Test with mixed 'BeArEr' prefix in Authorization header"""
+        backend = BearerAuthBackend(provider=mock_oauth_provider)
+        add_token_to_provider(mock_oauth_provider, "valid_token", valid_access_token)
+        headers = Headers({"authorization": "BeArEr valid_token"})
+        scope = {"type": "http", "headers": headers.raw}
+        request = Request(scope)
+        result = await backend.authenticate(request)
+        assert result is not None
+        credentials, user = result
+        assert isinstance(credentials, AuthCredentials)
+        assert isinstance(user, AuthenticatedUser)
+        assert credentials.scopes == ["read", "write"]
+        assert user.display_name == "test_client"
+        assert user.access_token == valid_access_token
+
+    async def test_mixed_case_authorization_header(
+        self,
+        mock_oauth_provider: OAuthAuthorizationServerProvider[Any, Any, Any],
+        valid_access_token: AccessToken,
+    ):
+        """Test authentication with mixed 'Authorization' header."""
+        backend = BearerAuthBackend(provider=mock_oauth_provider)
+        add_token_to_provider(mock_oauth_provider, "valid_token", valid_access_token)
+        headers = Headers({"AuThOrIzAtIoN": "BeArEr valid_token"})
+        scope = {"type": "http", "headers": headers.raw}
+        request = Request(scope)
+        result = await backend.authenticate(request)
+        assert result is not None
+        credentials, user = result
+        assert isinstance(credentials, AuthCredentials)
+        assert isinstance(user, AuthenticatedUser)
+        assert credentials.scopes == ["read", "write"]
+        assert user.display_name == "test_client"
+        assert user.access_token == valid_access_token
+
 
 @pytest.mark.anyio
 class TestRequireAuthMiddleware: