fix: No more BytesWarnings

Fixes #1236.

This patch makes all header operations operate on `bytes` and converts all headers and values to bytes before operation. With a follow up patch to `hpack` it should also increase efficiency as currently, `hpack` casts everything to a `str` first before converting back to bytes: https://github.com/python-hyper/hpack/blob/02afcab28ca56eb5259904fd414baa89e9f50266/src/hpack/hpack.py#L150-L151

src/h2/connection.py

@@ -33,7 +33,7 @@
 from .frame_buffer import FrameBuffer
 from .settings import Settings, SettingCodes
 from .stream import H2Stream, StreamClosedBy
-from .utilities import SizeLimitDict, guard_increment_window
+from .utilities import SizeLimitDict, guard_increment_window, utf8_encode_headers
 from .windows import WindowManager
 
 
@@ -976,6 +976,7 @@ def push_stream(self, stream_id, promised_stream_id, request_headers):
         )
         self.streams[promised_stream_id] = new_stream
 
+        request_headers = utf8_encode_headers(request_headers)
         frames = stream.push_stream_in_band(
             promised_stream_id, request_headers, self.encoder
         )

src/h2/events.py

@@ -589,11 +589,9 @@ def __init__(self):
         self.field_value = None
 
     def __repr__(self):
-        return (
-            "<AlternativeServiceAvailable origin:%s, field_value:%s>" % (
-                self.origin.decode('utf-8', 'ignore'),
-                self.field_value.decode('utf-8', 'ignore'),
-            )
+        return "<AlternativeServiceAvailable origin:%s, field_value:%s>" % (
+            self.origin.decode("utf-8", "replace"),
+            self.field_value.decode("utf-8", "replace"),
         )
 
 

src/h2/stream.py

@@ -23,9 +23,16 @@
     ProtocolError, StreamClosedError, InvalidBodyLengthError, FlowControlError
 )
 from .utilities import (
-    guard_increment_window, is_informational_response, authority_from_headers,
-    validate_headers, validate_outbound_headers, normalize_outbound_headers,
-    HeaderValidationFlags, extract_method_header, normalize_inbound_headers
+    guard_increment_window,
+    is_informational_response,
+    authority_from_headers,
+    utf8_encode_headers,
+    validate_headers,
+    validate_outbound_headers,
+    normalize_outbound_headers,
+    HeaderValidationFlags,
+    extract_method_header,
+    normalize_inbound_headers,
 )
 from .windows import WindowManager
 
@@ -851,8 +858,9 @@ def send_headers(self, headers, encoder, end_stream=False):
         # we need to scan the header block to see if this is an informational
         # response.
         input_ = StreamInputs.SEND_HEADERS
-        if ((not self.state_machine.client) and
-                is_informational_response(headers)):
+
+        headers = utf8_encode_headers(headers)
+        if (not self.state_machine.client) and is_informational_response(headers):
             if end_stream:
                 raise ProtocolError(
                     "Cannot set END_STREAM on informational responses."
@@ -1242,6 +1250,7 @@ def _build_headers_frames(self,
         """
         # We need to lowercase the header names, and to ensure that secure
         # header fields are kept out of compression contexts.
+
         if self.config.normalize_outbound_headers:
             # also we may want to split outbound cookies to improve
             # headers compression
@@ -1318,9 +1327,7 @@ def _initialize_content_length(self, headers):
                 try:
                     self._expected_content_length = int(v, 10)
                 except ValueError:
-                    raise ProtocolError(
-                        "Invalid content-length header: %s" % v
-                    )
+                    raise ProtocolError(f"Invalid content-length header: {repr(v)}")
 
                 return