Raise TooManyRedirects error when client gets redirected too many times

Closes aio-libs#2631

Author: roganov

CHANGES/2631.feature

@@ -0,0 +1,2 @@
+Raise ``TooManyRedirects`` exception when client gets redirected too many times
+instead of returning last response.

aiohttp/client.py

@@ -18,7 +18,8 @@
 from . import hdrs, http, payload
 from .client_exceptions import *  # noqa
 from .client_exceptions import (ClientError, ClientOSError, InvalidURL,
-                                ServerTimeoutError, WSServerHandshakeError)
+                                ServerTimeoutError, TooManyRedirects,
+                                WSServerHandshakeError)
 from .client_reqrep import *  # noqa
 from .client_reqrep import ClientRequest, ClientResponse, _merge_ssl_params
 from .client_ws import ClientWebSocketResponse
@@ -360,7 +361,8 @@ async def _request(self, method, url, *,
                         history.append(resp)
                         if max_redirects and redirects >= max_redirects:
                             resp.close()
-                            break
+                            raise TooManyRedirects(
+                                history[0].request_info, tuple(history))
                         else:
                             resp.release()
 

aiohttp/client_exceptions.py

@@ -93,6 +93,10 @@ class ClientHttpProxyError(ClientResponseError):
     """
 
 
+class TooManyRedirects(ClientResponseError):
+    """Client was redirected too many times."""
+
+
 class ClientConnectionError(ClientError):
     """Base class for client socket errors."""
 

docs/client_reference.rst

@@ -251,6 +251,9 @@ The client session supports the context manager protocol for self closing.
       :param bool allow_redirects: If set to ``False``, do not follow redirects.
                                    ``True`` by default (optional).
 
+      :param int max_redirects: Maximum number of redirects to follow.
+                                ``10`` by default.
+
       :param bool compress: Set to ``True`` if request has to be compressed
          with deflate encoding. If `compress` can not be combined
          with a *Content-Encoding* and *Content-Length* headers.
@@ -501,7 +504,7 @@ The client session supports the context manager protocol for self closing.
 
       :param bool autoclose: Automatically close websocket connection on close
                              message from server. If *autoclose* is False
-                             them close procedure has to be handled manually. 
+                             then close procedure has to be handled manually.
                              ``True`` by default
 
       :param bool autoping: automatically send *pong* on *ping*
@@ -514,7 +517,7 @@ The client session supports the context manager protocol for self closing.
                               reception.(optional)
 
       :param str origin: Origin header to send to server(optional)
-      
+
       :param dict headers: HTTP Headers to send with
                            the request (optional)
 
@@ -565,7 +568,7 @@ The client session supports the context manager protocol for self closing.
          authority channel, supported SSL options etc.
 
          .. versionadded:: 2.3
-         
+
          .. deprecated:: 3.0
 
             Use ``ssl=ssl_context``
@@ -1727,6 +1730,18 @@ Response errors
 
    .. versionadded:: 2.3
 
+
+.. class:: TooManyRedirects
+
+   Client was redirected too many times.
+
+   Maximum number of redirects can be configured by using
+   parameter ``max_redirects`` in :meth:`request<aiohttp.ClientSession.request>`.
+
+   Derived from :exc:`ClientResponseError`
+
+   .. versionadded:: 3.2
+
 Connection errors
 ^^^^^^^^^^^^^^^^^
 

tests/test_client_functional.py

@@ -16,6 +16,7 @@
 import aiohttp
 from aiohttp import Fingerprint, ServerFingerprintMismatch, hdrs, web
 from aiohttp.abc import AbstractResolver
+from aiohttp.client_exceptions import TooManyRedirects
 from aiohttp.test_utils import unused_port
 
 
@@ -914,10 +915,11 @@ async def redirect(request):
     app.router.add_get(r'/redirect/{count:\d+}', redirect)
     client = await aiohttp_client(app)
 
-    resp = await client.get('/redirect/5', max_redirects=2)
-    assert 302 == resp.status
-    assert 2 == len(resp.history)
-    resp.close()
+    with pytest.raises(TooManyRedirects) as ctx:
+        await client.get('/redirect/5', max_redirects=2)
+    assert 2 == len(ctx.value.history)
+    assert ctx.value.request_info.url.path == '/redirect/5'
+    assert ctx.value.request_info.method == 'GET'
 
 
 async def test_HTTP_200_GET_WITH_PARAMS(aiohttp_client):