Extend download error coverage

docs/topics/download-handlers.rst

@@ -118,10 +118,16 @@ these exceptions.
 
 .. autoexception:: scrapy.exceptions.DownloadCancelledError
 
+.. autoexception:: scrapy.exceptions.DownloadConnectBindError
+
 .. autoexception:: scrapy.exceptions.DownloadConnectionRefusedError
 
 .. autoexception:: scrapy.exceptions.DownloadFailedError
 
+.. autoexception:: scrapy.exceptions.DownloadNoRouteError
+
+.. autoexception:: scrapy.exceptions.DownloadTCPTimedOutError
+
 .. autoexception:: scrapy.exceptions.DownloadTimeoutError
 
 .. autoexception:: scrapy.exceptions.ResponseDataLossError

scrapy/core/downloader/handlers/_httpx.py

@@ -2,8 +2,10 @@
 
 from __future__ import annotations
 
+import errno
 import ipaddress
 import logging
+import socket
 import ssl
 import time
 from http.cookiejar import Cookie, CookieJar
@@ -14,8 +16,11 @@ from scrapy import Request, signals
 from scrapy.exceptions import (
     CannotResolveHostError,
     DownloadCancelledError,
+    DownloadConnectBindError,
     DownloadConnectionRefusedError,
     DownloadFailedError,
+    DownloadNoRouteError,
+    DownloadTCPTimedOutError,
     DownloadTimeoutError,
     NotConfigured,
     ResponseDataLossError,
@@ -53,6 +58,82 @@ except ImportError:
 logger = logging.getLogger(__name__)
 
 
+def _errno_values(*names: str) -> tuple[int, ...]:
+    return tuple(
+        value for name in names if (value := getattr(errno, name, None)) is not None
+    )
+
+
+_CONNECT_ERRNO_MAP: tuple[tuple[tuple[int, ...], type[Exception]], ...] = (
+    (_errno_values("ECONNREFUSED", "WSAECONNREFUSED"), DownloadConnectionRefusedError),
+    (
+        _errno_values(
+            "ENETUNREACH",
+            "EHOSTUNREACH",
+            "WSAENETUNREACH",
+            "WSAEHOSTUNREACH",
+        ),
+        DownloadNoRouteError,
+    ),
+    (_errno_values("ETIMEDOUT", "WSAETIMEDOUT"), DownloadTCPTimedOutError),
+    (
+        _errno_values(
+            "EADDRINUSE",
+            "EADDRNOTAVAIL",
+            "WSAEADDRINUSE",
+            "WSAEADDRNOTAVAIL",
+        ),
+        DownloadConnectBindError,
+    ),
+)
+
+
+def _find_nested_os_error(exc: BaseException) -> OSError | None:
+    fallback_os_error: OSError | None = None
+    to_visit: list[BaseException] = [exc]
+    seen: set[int] = set()
+    while to_visit:
+        current = to_visit.pop()
+        if id(current) in seen:
+            continue
+        seen.add(id(current))
+        if isinstance(current, OSError):
+            if isinstance(current, socket.gaierror) or current.errno is not None:
+                return current
+            if fallback_os_error is None:
+                fallback_os_error = current
+
+        next_exceptions = [current.__cause__, current.__context__]
+        to_visit.extend(
+            next_exception
+            for next_exception in next_exceptions
+            if isinstance(next_exception, BaseException)
+        )
+
+        grouped_exceptions = getattr(current, "exceptions", None)
+        if isinstance(grouped_exceptions, tuple):
+            to_visit.extend(
+                nested_exception
+                for nested_exception in grouped_exceptions
+                if isinstance(nested_exception, BaseException)
+            )
+
+    return fallback_os_error
+
+
+def _to_scrapy_connect_error(exc: httpx.ConnectError) -> Exception:
+    os_error = _find_nested_os_error(exc)
+    message = str(exc)
+    if os_error is None:
+        return DownloadFailedError(message)
+    if isinstance(os_error, socket.gaierror):
+        return CannotResolveHostError(message)
+    for errnos, scrapy_exc_cls in _CONNECT_ERRNO_MAP:
+        if os_error.errno in errnos:
+            return scrapy_exc_cls(message)
+    return DownloadFailedError(message)
+
+
 class _BaseResponseArgs(TypedDict):
     status: int
     url: str
@@ -133,6 +214,10 @@ class HttpxDownloadHandler(BaseHttpDownloadHandler):
             async with self._get_httpx_response(request, timeout) as httpx_response:
                 request.meta["download_latency"] = time.monotonic() - start_time
                 return await self._read_response(httpx_response, request)
+        except httpx.ConnectTimeout as e:
+            raise DownloadTCPTimedOutError(
+                f"Connecting to {request.url} took longer than {timeout} seconds."
+            ) from e
         except httpx.TimeoutException as e:
             raise DownloadTimeoutError(
                 f"Getting {request.url} took longer than {timeout} seconds."
@@ -140,15 +225,7 @@ class HttpxDownloadHandler(BaseHttpDownloadHandler):
         except httpx.UnsupportedProtocol as e:
             raise UnsupportedURLSchemeError(str(e)) from e
         except httpx.ConnectError as e:
-            error_message = str(e)
-            if (
-                "Name or service not known" in error_message
-                or "getaddrinfo failed" in error_message
-                or "nodename nor servname" in error_message
-                or "Temporary failure in name resolution" in error_message
-            ):
-                raise CannotResolveHostError(error_message) from e
-            raise DownloadConnectionRefusedError(str(e)) from e
+            raise _to_scrapy_connect_error(e) from e
         except httpx.NetworkError as e:
             raise DownloadFailedError(str(e)) from e
         except httpx.RemoteProtocolError as e:

scrapy/exceptions.py

@@ -63,10 +63,22 @@ class DownloadConnectionRefusedError(Exception):
     """Indicates that a connection was refused by the server."""
 
 
+class DownloadConnectBindError(Exception):
+    """Indicates that binding to a local address failed."""
+
+
 class CannotResolveHostError(Exception):
     """Indicates that the provided hostname cannot be resolved."""
 
 
+class DownloadNoRouteError(Exception):
+    """Indicates that no route to the remote host exists."""
+
+
+class DownloadTCPTimedOutError(Exception):
+    """Indicates that establishing a TCP connection timed out."""
+
+
 class DownloadTimeoutError(Exception):
     """Indicates that a request download has timed out."""
 

scrapy/settings/default_settings.py

@@ -458,8 +458,11 @@ REQUEST_FINGERPRINTER_CLASS = "scrapy.utils.request.RequestFingerprinter"
 RETRY_ENABLED = True
 RETRY_EXCEPTIONS = [
     "scrapy.exceptions.CannotResolveHostError",
+    "scrapy.exceptions.DownloadConnectBindError",
     "scrapy.exceptions.DownloadConnectionRefusedError",
     "scrapy.exceptions.DownloadFailedError",
+    "scrapy.exceptions.DownloadNoRouteError",
+    "scrapy.exceptions.DownloadTCPTimedOutError",
     "scrapy.exceptions.DownloadTimeoutError",
     "scrapy.exceptions.ResponseDataLossError",
     "twisted.internet.error.ConnectionDone",

scrapy/utils/_download_handlers.py

@@ -7,9 +7,14 @@ from contextlib import contextmanager
 from typing import TYPE_CHECKING, Any
 
 from twisted.internet.defer import CancelledError
+from twisted.internet.error import ConnectBindError as TxConnectBindError
+from twisted.internet.error import ConnectError as TxConnectError
 from twisted.internet.error import ConnectionRefusedError as TxConnectionRefusedError
 from twisted.internet.error import DNSLookupError
+from twisted.internet.error import NoRouteError as TxNoRouteError
+from twisted.internet.error import TCPTimedOutError as TxTCPTimedOutError
 from twisted.internet.error import TimeoutError as TxTimeoutError
+from twisted.internet.error import UnknownHostError as TxUnknownHostError
 from twisted.python.failure import Failure
 from twisted.web.client import ResponseFailed
 from twisted.web.error import SchemeNotSupported
@@ -19,8 +24,11 @@ from scrapy.core.downloader.handlers.base import BaseDownloadHandler
 from scrapy.exceptions import (
     CannotResolveHostError,
     DownloadCancelledError,
+    DownloadConnectBindError,
     DownloadConnectionRefusedError,
     DownloadFailedError,
+    DownloadNoRouteError,
+    DownloadTCPTimedOutError,
     DownloadTimeoutError,
     StopDownload,
     UnsupportedURLSchemeError,
@@ -54,6 +62,44 @@ class BaseHttpDownloadHandler(BaseDownloadHandler, ABC):
         self._fail_on_dataloss_warned: bool = False
 
 
+_TWISTED_CONNECT_ERROR_MAP: tuple[
+    tuple[type[TxConnectError], type[Exception]],
+    ...,
+] = (
+    (TxConnectionRefusedError, DownloadConnectionRefusedError),
+    (TxConnectBindError, DownloadConnectBindError),
+    (TxUnknownHostError, CannotResolveHostError),
+    (TxNoRouteError, DownloadNoRouteError),
+    (TxTCPTimedOutError, DownloadTCPTimedOutError),
+    (TxTimeoutError, DownloadTimeoutError),
+)
+
+
+def _map_twisted_connect_exception(exc: TxConnectError) -> Exception:
+    message = str(exc)
+    for twisted_exc_cls, scrapy_exc_cls in _TWISTED_CONNECT_ERROR_MAP:
+        if isinstance(exc, twisted_exc_cls):
+            return scrapy_exc_cls(message)
+    return DownloadFailedError(message)
+
+
+def _map_response_failed_exception(exc: ResponseFailed) -> Exception | None:
+    mapped_exception: Exception | None = None
+    for reason in exc.reasons:
+        if isinstance(reason.value, TxConnectError):
+            current_exception: Exception = _map_twisted_connect_exception(reason.value)
+        elif isinstance(reason.value, DNSLookupError):
+            current_exception = CannotResolveHostError(str(reason.value))
+        else:
+            return None
+        if mapped_exception is None:
+            mapped_exception = current_exception
+            continue
+        if type(mapped_exception) is not type(current_exception):
+            return None
+    return mapped_exception
+
+
 @contextmanager
 def wrap_twisted_exceptions() -> Iterator[None]:
     """Context manager that wraps Twisted exceptions into Scrapy exceptions."""
@@ -63,14 +109,14 @@ def wrap_twisted_exceptions() -> Iterator[None]:
         raise UnsupportedURLSchemeError(str(e)) from e
     except CancelledError as e:
         raise DownloadCancelledError(str(e)) from e
-    except TxConnectionRefusedError as e:
-        raise DownloadConnectionRefusedError(str(e)) from e
     except DNSLookupError as e:
         raise CannotResolveHostError(str(e)) from e
+    except TxConnectError as e:
+        raise _map_twisted_connect_exception(e) from e
     except ResponseFailed as e:
+        if mapped_exception := _map_response_failed_exception(e):
+            raise mapped_exception from e
         raise DownloadFailedError(str(e)) from e
-    except TxTimeoutError as e:
-        raise DownloadTimeoutError(str(e)) from e
 
 
 def check_stop_download(

tests/test_downloader_handlers_http_base.py

@@ -6,6 +6,7 @@ import gzip
 import json
 import platform
 import re
+import socket
 import sys
 from abc import ABC, abstractmethod
 from contextlib import asynccontextmanager
@@ -22,6 +23,7 @@ from twisted.python.failure import Failure
 from scrapy.exceptions import (
     CannotResolveHostError,
     DownloadCancelledError,
+    DownloadConnectBindError,
     DownloadConnectionRefusedError,
     DownloadFailedError,
     DownloadTimeoutError,
@@ -523,6 +525,15 @@ class TestHttpBase(ABC):
 class TestHttp11Base(TestHttpBase):
     """HTTP 1.1 test case"""
 
+    @staticmethod
+    def _system_allows_nonlocal_bind() -> bool:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            try:
+                sock.bind(("198.51.100.1", 0))
+            except OSError:
+                return False
+        return True
+
     @coroutine_test
     async def test_download_without_maxsize_limit(self, mockserver: MockServer) -> None:
         request = Request(mockserver.url("/text", is_secure=self.is_secure))
@@ -748,6 +759,18 @@ class TestHttp11Base(TestHttpBase):
             response = await download_handler.download_request(request)
         assert response.body == b"127.0.0.2"
 
+    @coroutine_test
+    async def test_download_bind_address_nonlocal(self, mockserver: MockServer) -> None:
+        if self._system_allows_nonlocal_bind():
+            pytest.skip("This system allows binding to non-local addresses")
+
+        request = Request(mockserver.url("/text", is_secure=self.is_secure))
+        async with self.get_dh(
+            {"DOWNLOAD_BIND_ADDRESS": ("198.51.100.1", 0)}
+        ) as download_handler:
+            with pytest.raises(DownloadConnectBindError):
+                await download_handler.download_request(request)
+
     @pytest.mark.skipif(
         sys.platform == "darwin",
         reason="127.0.0.2 is not available on macOS by default",

tests/test_downloadermiddleware_retry.py

@@ -7,7 +7,10 @@ from twisted.internet.error import ConnectError, ConnectionDone, ConnectionLost
 from scrapy.downloadermiddlewares.retry import RetryMiddleware, get_retry_request
 from scrapy.exceptions import (
     CannotResolveHostError,
+    DownloadConnectBindError,
     DownloadConnectionRefusedError,
+    DownloadNoRouteError,
+    DownloadTCPTimedOutError,
     DownloadTimeoutError,
     IgnoreRequest,
 )
@@ -90,8 +93,11 @@ class TestRetry:
             ConnectionDone,
             ConnectionLost,
             DownloadTimeoutError,
+            DownloadTCPTimedOutError,
             DownloadConnectionRefusedError,
+            DownloadConnectBindError,
             CannotResolveHostError,
+            DownloadNoRouteError,
         ]
 
         for exc in exceptions: