Use aiohttp middleware for mocking (#170)

This solves a host of issues, including #166, as well as that middlwares would not have previously worked. It might also solve #152 but I have not tested that yet.

Author: sarayourfriend

src/pook/interceptors/aiohttp.py

@@ -1,9 +1,7 @@
-import asyncio
 from http.client import responses as http_reasons
-from typing import Callable, Optional
+from typing import Optional
 from unittest import mock
-from urllib.parse import urlencode, urlunparse
-from collections.abc import Mapping
+from urllib.parse import urlunparse
 
 import aiohttp
 from aiohttp.helpers import TimerNoop
@@ -16,111 +14,29 @@
 import multidict
 import yarl
 
-PATCHES = ("aiohttp.client.ClientSession._request",)
-
 RESPONSE_CLASS = "ClientResponse"
 RESPONSE_PATH = "aiohttp.client_reqrep"
 
 
-class SimpleContent(EmptyStreamReader):
-    def __init__(self, content, *args, **kwargs):
-        super().__init__(*args, **kwargs)
-        self.content = content
-
-    async def read(self, n=-1):
-        return self.content
-
-
-def HTTPResponse(session: aiohttp.ClientSession, *args, **kw):
-    return session._response_class(
-        *args,
-        request_info=mock.Mock(),
-        writer=None,
-        continue100=None,
-        timer=TimerNoop(),
-        traces=[],
-        loop=mock.Mock(),
-        session=mock.Mock(),
-        **kw,
-    )
-
-
 class AIOHTTPInterceptor(BaseInterceptor):
-    """
-    aiohttp HTTP client traffic interceptor.
-    """
-
-    def _url(self, url) -> Optional[yarl.URL]:
-        return yarl.URL(url) if yarl else None
-
-    def set_headers(self, req, headers) -> None:
-        # aiohttp's interface allows various mappings, as well as an iterable of key/value tuples
-        # ``pook.request`` only allows a dict, so we need to map the iterable to the matchable interface
-        if headers:
-            if isinstance(headers, Mapping):
-                req.headers.update(**headers)
-            else:
-                # If it isn't a mapping, then its an Iterable[Tuple[Union[str, istr], str]]
-                for req_header, req_header_value in headers:
-                    normalised_header = req_header.lower()
-                    if normalised_header in req.headers:
-                        req.headers[normalised_header] += f", {req_header_value}"
-                    else:
-                        req.headers[normalised_header] = req_header_value
-
-    async def _on_request(
-        self,
-        _request: Callable,
-        session: aiohttp.ClientSession,
-        method: str,
-        url: str,
-        data=None,
-        headers=None,
-        **kw,
+    # Implements aiohttp.ClientMiddlewareType
+    async def __call__(
+        self, request: aiohttp.ClientRequest, handler: aiohttp.ClientHandlerType
     ) -> aiohttp.ClientResponse:
-        # Create request contract based on incoming params
-        req = Request(method)
-
-        self.set_headers(req, headers)
-        self.set_headers(req, session.headers)
-
-        req.body = data
-
-        # Expose extra variadic arguments
-        req.extra = kw
-
-        full_url = session._build_url(url)
+        req = Request(
+            method=request.method,
+            headers=request.headers.items(),
+            body=request.body,
+            url=str(request.url),
+        )
 
-        # Compose URL
-        if not kw.get("params"):
-            req.url = str(full_url)
-        else:
-            # Transform params as a list of tuple
-            params = kw["params"]
-            if isinstance(params, dict):
-                params = [(x, y) for x, y in kw["params"].items()]
-            req.url = str(full_url) + "?" + urlencode(params)
-
-        # If a json payload is provided, serialize it for JSONMatcher support
-        if json_body := kw.get("json"):
-            req.json = json_body
-            if "Content-Type" not in req.headers:
-                req.headers["Content-Type"] = "application/json"
-
-        # Match the request against the registered mocks in pook
         mock = self.engine.match(req)
 
         # If cannot match any mock, run real HTTP request if networking
         # or silent model are enabled, otherwise this statement won't
         # be reached (an exception will be raised before).
         if not mock:
-            return await _request(
-                session, method, url, data=data, headers=headers, **kw
-            )
-
-        # Simulate network delay
-        if mock._delay:
-            await asyncio.sleep(mock._delay / 1000)  # noqa
+            return await handler(request)
 
         # Shortcut to mock response
         res = mock._response
@@ -131,7 +47,7 @@ async def _on_request(
             headers.append((key, res._headers[key]))
 
         # Create mock equivalent HTTP response
-        _res = HTTPResponse(session, req.method, self._url(urlunparse(req.url)))
+        _res = HTTPResponse(request.session, req.method, self._url(urlunparse(req.url)))
 
         # response status
         _res.version = aiohttp.HttpVersion(1, 1)
@@ -154,23 +70,24 @@ async def _on_request(
         # Return response based on mock definition
         return _res
 
-    def _patch(self, path: str) -> None:
+    def _url(self, url) -> Optional[yarl.URL]:
+        return yarl.URL(url) if yarl else None
+
+    def activate(self) -> None:
         # If not able to import aiohttp dependencies, skip
         if not yarl or not multidict:
             return None
 
-        async def handler(session, method, url, data=None, headers=None, **kw):
-            return await self._on_request(
-                _request, session, method, url, data=data, headers=headers, **kw
-            )
+        def _request(session, *args, **kwargs):
+            request_middlewares = kwargs.get("middlewares", ())
+            kwargs["middlewares"] = request_middlewares + (self,)
+            return super_request(session, *args, **kwargs)
 
         try:
-            # Create a new patcher for Urllib3 urlopen function
-            # used as entry point for all the HTTP communications
-            patcher = mock.patch(path, handler)
-            # Retrieve original patched function that we might need for real
-            # networking
-            _request = patcher.get_original()[0]
+            # Patch ClientSession init to append this interceptor as an aiohttp
+            # middleware to all session's middlewares
+            patcher = mock.patch("aiohttp.client.ClientSession._request", _request)
+            super_request = patcher.get_original()[0]
             # Start patching function calls
             patcher.start()
         except Exception:
@@ -180,18 +97,33 @@ async def handler(session, method, url, data=None, headers=None, **kw):
         else:
             self.patchers.append(patcher)
 
-    def activate(self) -> None:
-        """
-        Activates the traffic interceptor.
-        This method must be implemented by any interceptor.
-        """
-        for path in PATCHES:
-            self._patch(path)
-
     def disable(self) -> None:
         """
         Disables the traffic interceptor.
         This method must be implemented by any interceptor.
         """
         for patch in self.patchers:
             patch.stop()
+
+
+class SimpleContent(EmptyStreamReader):
+    def __init__(self, content, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.content = content
+
+    async def read(self, n=-1):
+        return self.content
+
+
+def HTTPResponse(session: aiohttp.ClientSession, *args, **kw):
+    return session._response_class(
+        *args,
+        request_info=mock.Mock(),
+        writer=None,
+        continue100=None,
+        timer=TimerNoop(),
+        traces=[],
+        loop=mock.Mock(),
+        session=mock.Mock(),
+        **kw,
+    )

src/pook/request.py

@@ -54,8 +54,6 @@ def headers(self):
 
     @headers.setter
     def headers(self, headers):
-        if not hasattr(headers, "__setitem__"):
-            raise TypeError("headers must be a dictionary")
         self._headers.extend(headers)
 
     @property

tests/unit/interceptors/aiohttp_test.py

@@ -97,6 +97,22 @@ async def test_client_headers_merged(local_responder):
         assert await res.read() == b"hello from pook"
 
 
+@pytest.mark.asyncio
+async def test_client_auth_merged(local_responder):
+    """Auth headers set on the client should be matched"""
+    pook.get(local_responder + "/status/404").header(
+        "Authorization", "Basic dXNlcjpwYXNzd29yZA=="
+    ).reply(200).body("hello from pook")
+    async with aiohttp.ClientSession(
+        auth=aiohttp.BasicAuth("user", "password")
+    ) as session:
+        res = await session.get(
+            local_responder + "/status/404", headers={"x-pook-secondary": "xyz"}
+        )
+        assert res.status == 200
+        assert await res.read() == b"hello from pook"
+
+
 @pytest.mark.asyncio
 async def test_client_headers_both_session_and_request(local_responder):
     """Headers should be matchable from both the session and request in the same matcher"""