Push httpcore exception wrapping out of client into transport (#1524)

* Push httpcore exception wrapping out of client into transport

* Include close/aclose extensions in docstring

* Comment about the request property on RequestError exceptions

httpx/_client.py

@@ -18,11 +18,10 @@
 )
 from ._decoders import SUPPORTED_DECODERS
 from ._exceptions import (
-    HTTPCORE_EXC_MAP,
     InvalidURL,
     RemoteProtocolError,
     TooManyRedirects,
-    map_exceptions,
+    request_context,
 )
 from ._models import URL, Cookies, Headers, QueryParams, Request, Response
 from ._status_codes import codes
@@ -849,7 +848,7 @@ def _send_single_request(self, request: Request, timeout: Timeout) -> Response:
         timer = Timer()
         timer.sync_start()
 
-        with map_exceptions(HTTPCORE_EXC_MAP, request=request):
+        with request_context(request=request):
             (status_code, headers, stream, extensions) = transport.handle_request(
                 request.method.encode(),
                 request.url.raw,
@@ -860,13 +859,13 @@ def _send_single_request(self, request: Request, timeout: Timeout) -> Response:
 
         def on_close(response: Response) -> None:
             response.elapsed = datetime.timedelta(seconds=timer.sync_elapsed())
-            if hasattr(stream, "close"):
-                stream.close()  # type: ignore
+            if "close" in extensions:
+                extensions["close"]()
 
         response = Response(
             status_code,
             headers=headers,
-            stream=stream,  # type: ignore
+            stream=stream,
             extensions=extensions,
             request=request,
             on_close=on_close,
@@ -1483,7 +1482,7 @@ async def _send_single_request(
         timer = Timer()
         await timer.async_start()
 
-        with map_exceptions(HTTPCORE_EXC_MAP, request=request):
+        with request_context(request=request):
             (
                 status_code,
                 headers,
@@ -1499,14 +1498,13 @@ async def _send_single_request(
 
         async def on_close(response: Response) -> None:
             response.elapsed = datetime.timedelta(seconds=await timer.async_elapsed())
-            if hasattr(stream, "aclose"):
-                with map_exceptions(HTTPCORE_EXC_MAP, request=request):
-                    await stream.aclose()  # type: ignore
+            if "aclose" in extensions:
+                await extensions["aclose"]()
 
         response = Response(
             status_code,
             headers=headers,
-            stream=stream,  # type: ignore
+            stream=stream,
             extensions=extensions,
             request=request,
             on_close=on_close,

httpx/_decoders.py

@@ -8,6 +8,8 @@
 import typing
 import zlib
 
+from ._exceptions import DecodingError
+
 try:
     import brotli
 except ImportError:  # pragma: nocover
@@ -54,13 +56,13 @@ def decode(self, data: bytes) -> bytes:
             if was_first_attempt:
                 self.decompressor = zlib.decompressobj(-zlib.MAX_WBITS)
                 return self.decode(data)
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
     def flush(self) -> bytes:
         try:
             return self.decompressor.flush()
         except zlib.error as exc:  # pragma: nocover
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
 
 class GZipDecoder(ContentDecoder):
@@ -77,13 +79,13 @@ def decode(self, data: bytes) -> bytes:
         try:
             return self.decompressor.decompress(data)
         except zlib.error as exc:
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
     def flush(self) -> bytes:
         try:
             return self.decompressor.flush()
         except zlib.error as exc:  # pragma: nocover
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
 
 class BrotliDecoder(ContentDecoder):
@@ -118,7 +120,7 @@ def decode(self, data: bytes) -> bytes:
         try:
             return self._decompress(data)
         except brotli.error as exc:
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
     def flush(self) -> bytes:
         if not self.seen_data:
@@ -128,7 +130,7 @@ def flush(self) -> bytes:
                 self.decompressor.finish()
             return b""
         except brotli.error as exc:  # pragma: nocover
-            raise ValueError(str(exc))
+            raise DecodingError(str(exc)) from exc
 
 
 class MultiDecoder(ContentDecoder):

httpx/_exceptions.py

@@ -34,8 +34,6 @@
 import contextlib
 import typing
 
-import httpcore
-
 if typing.TYPE_CHECKING:
     from ._models import Request, Response  # pragma: nocover
 
@@ -58,25 +56,39 @@ class HTTPError(Exception):
     ```
     """
 
-    def __init__(self, message: str, *, request: "Request") -> None:
+    def __init__(self, message: str) -> None:
         super().__init__(message)
-        self.request = request
 
 
 class RequestError(HTTPError):
     """
     Base class for all exceptions that may occur when issuing a `.request()`.
     """
 
-    def __init__(self, message: str, *, request: "Request") -> None:
-        super().__init__(message, request=request)
+    def __init__(self, message: str, *, request: "Request" = None) -> None:
+        super().__init__(message)
+        # At the point an exception is raised we won't typically have a request
+        # instance to associate it with.
+        #
+        # The 'request_context' context manager is used within the Client and
+        # Response methods in order to ensure that any raised exceptions
+        # have a `.request` property set on them.
+        self._request = request
+
+    @property
+    def request(self) -> "Request":
+        if self._request is None:
+            raise RuntimeError("The .request property has not been set.")
+        return self._request
+
+    @request.setter
+    def request(self, request: "Request") -> None:
+        self._request = request
 
 
 class TransportError(RequestError):
     """
     Base class for all exceptions that occur at the level of the Transport API.
-
-    All of these exceptions also have an equivelent mapping in `httpcore`.
     """
 
 
@@ -219,7 +231,8 @@ class HTTPStatusError(HTTPError):
     def __init__(
         self, message: str, *, request: "Request", response: "Response"
     ) -> None:
-        super().__init__(message, request=request)
+        super().__init__(message)
+        self.request = request
         self.response = response
 
 
@@ -318,45 +331,14 @@ def __init__(self) -> None:
 
 
 @contextlib.contextmanager
-def map_exceptions(
-    mapping: typing.Mapping[typing.Type[Exception], typing.Type[Exception]],
-    **kwargs: typing.Any,
-) -> typing.Iterator[None]:
+def request_context(request: "Request" = None) -> typing.Iterator[None]:
+    """
+    A context manager that can be used to attach the given request context
+    to any `RequestError` exceptions that are raised within the block.
+    """
     try:
         yield
-    except Exception as exc:
-        mapped_exc = None
-
-        for from_exc, to_exc in mapping.items():
-            if not isinstance(exc, from_exc):
-                continue
-            # We want to map to the most specific exception we can find.
-            # Eg if `exc` is an `httpcore.ReadTimeout`, we want to map to
-            # `httpx.ReadTimeout`, not just `httpx.TimeoutException`.
-            if mapped_exc is None or issubclass(to_exc, mapped_exc):
-                mapped_exc = to_exc
-
-        if mapped_exc is None:
-            raise
-
-        message = str(exc)
-        raise mapped_exc(message, **kwargs) from exc  # type: ignore
-
-
-HTTPCORE_EXC_MAP = {
-    httpcore.TimeoutException: TimeoutException,
-    httpcore.ConnectTimeout: ConnectTimeout,
-    httpcore.ReadTimeout: ReadTimeout,
-    httpcore.WriteTimeout: WriteTimeout,
-    httpcore.PoolTimeout: PoolTimeout,
-    httpcore.NetworkError: NetworkError,
-    httpcore.ConnectError: ConnectError,
-    httpcore.ReadError: ReadError,
-    httpcore.WriteError: WriteError,
-    httpcore.CloseError: CloseError,
-    httpcore.ProxyError: ProxyError,
-    httpcore.UnsupportedProtocol: UnsupportedProtocol,
-    httpcore.ProtocolError: ProtocolError,
-    httpcore.LocalProtocolError: LocalProtocolError,
-    httpcore.RemoteProtocolError: RemoteProtocolError,
-}
+    except RequestError as exc:
+        if request is not None:
+            exc.request = request
+        raise exc

httpx/_models.py

@@ -1,5 +1,4 @@
 import cgi
-import contextlib
 import datetime
 import email.message
 import json as jsonlib
@@ -24,16 +23,14 @@
     TextDecoder,
 )
 from ._exceptions import (
-    HTTPCORE_EXC_MAP,
     CookieConflict,
-    DecodingError,
     HTTPStatusError,
     InvalidURL,
     RequestNotRead,
     ResponseClosed,
     ResponseNotRead,
     StreamConsumed,
-    map_exceptions,
+    request_context,
 )
 from ._status_codes import codes
 from ._types import (
@@ -1145,17 +1142,6 @@ def num_bytes_downloaded(self) -> int:
     def __repr__(self) -> str:
         return f"<Response [{self.status_code} {self.reason_phrase}]>"
 
-    @contextlib.contextmanager
-    def _wrap_decoder_errors(self) -> typing.Iterator[None]:
-        # If the response has an associated request instance, we want decoding
-        # errors to be raised as proper `httpx.DecodingError` exceptions.
-        try:
-            yield
-        except ValueError as exc:
-            if self._request is None:
-                raise exc
-            raise DecodingError(message=str(exc), request=self.request) from exc
-
     def read(self) -> bytes:
         """
         Read and return the response content.
@@ -1176,7 +1162,7 @@ def iter_bytes(self, chunk_size: int = None) -> typing.Iterator[bytes]:
         else:
             decoder = self._get_content_decoder()
             chunker = ByteChunker(chunk_size=chunk_size)
-            with self._wrap_decoder_errors():
+            with request_context(request=self._request):
                 for raw_bytes in self.iter_raw():
                     decoded = decoder.decode(raw_bytes)
                     for chunk in chunker.decode(decoded):
@@ -1195,7 +1181,7 @@ def iter_text(self, chunk_size: int = None) -> typing.Iterator[str]:
         """
         decoder = TextDecoder(encoding=self.encoding)
         chunker = TextChunker(chunk_size=chunk_size)
-        with self._wrap_decoder_errors():
+        with request_context(request=self._request):
             for byte_content in self.iter_bytes():
                 text_content = decoder.decode(byte_content)
                 for chunk in chunker.decode(text_content):
@@ -1208,7 +1194,7 @@ def iter_text(self, chunk_size: int = None) -> typing.Iterator[str]:
 
     def iter_lines(self) -> typing.Iterator[str]:
         decoder = LineDecoder()
-        with self._wrap_decoder_errors():
+        with request_context(request=self._request):
             for text in self.iter_text():
                 for line in decoder.decode(text):
                     yield line
@@ -1230,7 +1216,7 @@ def iter_raw(self, chunk_size: int = None) -> typing.Iterator[bytes]:
         self._num_bytes_downloaded = 0
         chunker = ByteChunker(chunk_size=chunk_size)
 
-        with map_exceptions(HTTPCORE_EXC_MAP, request=self._request):
+        with request_context(request=self._request):
             for raw_stream_bytes in self.stream:
                 self._num_bytes_downloaded += len(raw_stream_bytes)
                 for chunk in chunker.decode(raw_stream_bytes):
@@ -1249,7 +1235,8 @@ def close(self) -> None:
         if not self.is_closed:
             self.is_closed = True
             if self._on_close is not None:
-                self._on_close(self)
+                with request_context(request=self._request):
+                    self._on_close(self)
 
     async def aread(self) -> bytes:
         """
@@ -1271,7 +1258,7 @@ async def aiter_bytes(self, chunk_size: int = None) -> typing.AsyncIterator[byte
         else:
             decoder = self._get_content_decoder()
             chunker = ByteChunker(chunk_size=chunk_size)
-            with self._wrap_decoder_errors():
+            with request_context(request=self._request):
                 async for raw_bytes in self.aiter_raw():
                     decoded = decoder.decode(raw_bytes)
                     for chunk in chunker.decode(decoded):
@@ -1290,7 +1277,7 @@ async def aiter_text(self, chunk_size: int = None) -> typing.AsyncIterator[str]:
         """
         decoder = TextDecoder(encoding=self.encoding)
         chunker = TextChunker(chunk_size=chunk_size)
-        with self._wrap_decoder_errors():
+        with request_context(request=self._request):
             async for byte_content in self.aiter_bytes():
                 text_content = decoder.decode(byte_content)
                 for chunk in chunker.decode(text_content):
@@ -1303,7 +1290,7 @@ async def aiter_text(self, chunk_size: int = None) -> typing.AsyncIterator[str]:
 
     async def aiter_lines(self) -> typing.AsyncIterator[str]:
         decoder = LineDecoder()
-        with self._wrap_decoder_errors():
+        with request_context(request=self._request):
             async for text in self.aiter_text():
                 for line in decoder.decode(text):
                     yield line
@@ -1325,7 +1312,7 @@ async def aiter_raw(self, chunk_size: int = None) -> typing.AsyncIterator[bytes]
         self._num_bytes_downloaded = 0
         chunker = ByteChunker(chunk_size=chunk_size)
 
-        with map_exceptions(HTTPCORE_EXC_MAP, request=self._request):
+        with request_context(request=self._request):
             async for raw_stream_bytes in self.stream:
                 self._num_bytes_downloaded += len(raw_stream_bytes)
                 for chunk in chunker.decode(raw_stream_bytes):
@@ -1344,7 +1331,8 @@ async def aclose(self) -> None:
         if not self.is_closed:
             self.is_closed = True
             if self._on_close is not None:
-                await self._on_close(self)
+                with request_context(request=self._request):
+                    await self._on_close(self)
 
 
 class Cookies(MutableMapping):