Add config option to pass raw h11 headers

docs/how_to_guides/configuring.rst

@@ -108,6 +108,9 @@ read_timeout               ``--read-timeout``            Seconds to wait before
 group                      ``-g``, ``--group``           Group to own any unix sockets.
 h11_max_incomplete_size    N/A                           The max HTTP/1.1 request line + headers         16KiB
                                                          size in bytes.
+h11_pass_raw_headers       N/A                           Pass the raw headers from h11 to the          ``False``
+                                                         Request object, which preserves header
+                                                         casing.
 h2_max_concurrent_streams  N/A                           Maximum number of HTTP/2 concurrent             100
                                                          streams.
 h2_max_header_list_size    N/A                           Maximum number of HTTP/2 headers.               65536

src/hypercorn/config.py

@@ -77,6 +77,7 @@ class Config:
     read_timeout: Optional[int] = None
     group: Optional[int] = None
     h11_max_incomplete_size = 16 * 1024 * BYTES
+    h11_pass_raw_headers = False
     h2_max_concurrent_streams = 100
     h2_max_header_list_size = 2**16
     h2_max_inbound_frame_size = 2**14 * OCTETS

src/hypercorn/protocol/h11.py

@@ -219,10 +219,17 @@ async def _create_stream(self, request: h11.Request) -> None:
                 self.stream_send,
                 STREAM_ID,
             )
+
+        if self.config.h11_pass_raw_headers:
+            # uses unmodified header names as they are passed by the client
+            headers = request.headers.raw_items()
+        else:
+            headers = list(request.headers)
+
         await self.stream.handle(
             Request(
                 stream_id=STREAM_ID,
-                headers=list(request.headers),
+                headers=headers,
                 http_version=request.http_version.decode(),
                 method=request.method.decode("ascii").upper(),
                 raw_path=request.target,

tests/protocol/test_h11.py

@@ -197,6 +197,33 @@ async def test_protocol_handle_request(protocol: H11Protocol) -> None:
     ]
 
 
+@pytest.mark.asyncio
+async def test_protocol_handle_request_with_raw_headers(protocol: H11Protocol) -> None:
+    protocol.config.h11_pass_raw_headers = True
+    client = h11.Connection(h11.CLIENT)
+    headers = BASIC_HEADERS + [('FOO_BAR', 'foobar')]
+    await protocol.handle(
+        RawData(data=client.send(h11.Request(method="GET", target="/?a=b", headers=headers)))
+    )
+    protocol.stream.handle.assert_called()  # type: ignore
+    assert protocol.stream.handle.call_args_list == [  # type: ignore
+        call(
+            Request(
+                stream_id=1,
+                headers=[
+                    (b"Host", b"hypercorn"),
+                    (b"Connection", b"close"),
+                    (b"FOO_BAR", b"foobar"),
+                ],
+                http_version="1.1",
+                method="GET",
+                raw_path=b"/?a=b",
+            )
+        ),
+        call(EndBody(stream_id=1)),
+    ]
+
+
 @pytest.mark.asyncio
 async def test_protocol_handle_protocol_error(protocol: H11Protocol) -> None:
     await protocol.handle(RawData(data=b"broken nonsense\r\n\r\n"))