1.7.1

For Tornado AsyncHTTPClient, replace the methods instead of the class.

README.rst

@@ -608,6 +608,8 @@ new API in version 1.0.x
 
 Changelog
 ---------
+-  1.7.1 [#183] Patch ``fetch_impl`` instead of the entire HTTPClient
+   class for Tornado (thanks @abhinav).
 -  1.7.0 [#177] Properly support coroutine/generator decoration. [#178]
    Support distribute (thanks @graingert). [#163] Make compatibility
    between python2 and python3 recorded cassettes more robust (thanks

setup.py

@@ -9,6 +9,7 @@ import pkg_resources
 
 long_description = open('README.rst', 'r').read()
 
+
 class PyTest(TestCommand):
 
     def finalize_options(self):
@@ -23,7 +24,7 @@ class PyTest(TestCommand):
         sys.exit(errno)
 
 
-install_requires=['PyYAML', 'wrapt', 'six>=1.5']
+install_requires = ['PyYAML', 'wrapt', 'six>=1.5']
 
 
 extras_require = {
@@ -47,9 +48,10 @@ except Exception:
         if key.startswith(':'):
             install_requires.extend(value)
 
+
 setup(
     name='vcrpy',
-    version='1.7.0',
+    version='1.7.1',
     description=(
         "Automatically mock your HTTP interactions to simplify and "
         "speed up testing"

tests/integration/test_tornado.py

@@ -298,3 +298,31 @@ def test_tornado_exception_can_be_caught(get_client):
         yield get(get_client(), 'http://httpbin.org/status/404')
     except http.HTTPError as e:
         assert e.code == 404
+
+
+@pytest.mark.gen_test
+def test_existing_references_get_patched(tmpdir):
+    from tornado.httpclient import AsyncHTTPClient
+
+    with vcr.use_cassette(str(tmpdir.join('data.yaml'))):
+        client = AsyncHTTPClient()
+        yield get(client, 'http://httpbin.org/get')
+
+    with vcr.use_cassette(str(tmpdir.join('data.yaml'))) as cass:
+        yield get(client, 'http://httpbin.org/get')
+        assert cass.play_count == 1
+
+
+@pytest.mark.gen_test
+def test_existing_instances_get_patched(get_client, tmpdir):
+    '''Ensure that existing instances of AsyncHTTPClient get patched upon
+    entering VCR context.'''
+
+    client = get_client()
+
+    with vcr.use_cassette(str(tmpdir.join('data.yaml'))):
+        yield get(client, 'http://httpbin.org/get')
+
+    with vcr.use_cassette(str(tmpdir.join('data.yaml'))) as cass:
+        yield get(client, 'http://httpbin.org/get')
+        assert cass.play_count == 1

vcr/patch.py

@@ -54,13 +54,12 @@ else:
 
 # Try to save the original types for Tornado
 try:
-    import tornado.httpclient
     import tornado.simple_httpclient
 except ImportError:  # pragma: no cover
     pass
 else:
-    _AsyncHTTPClient = tornado.httpclient.AsyncHTTPClient
+    _SimpleAsyncHTTPClient_fetch_impl = \
-    _SimpleAsyncHTTPClient = tornado.simple_httpclient.SimpleAsyncHTTPClient
+            tornado.simple_httpclient.SimpleAsyncHTTPClient.fetch_impl
 
 
 try:
@@ -68,7 +67,8 @@ try:
 except ImportError:  # pragma: no cover
     pass
 else:
-    _CurlAsyncHTTPClient = tornado.curl_httpclient.CurlAsyncHTTPClient
+    _CurlAsyncHTTPClient_fetch_impl = \
+            tornado.curl_httpclient.CurlAsyncHTTPClient.fetch_impl
 
 
 class CassettePatcherBuilder(object):
@@ -228,23 +228,27 @@ class CassettePatcherBuilder(object):
     @_build_patchers_from_mock_triples_decorator
     def _tornado(self):
         try:
-            import tornado.httpclient as http
             import tornado.simple_httpclient as simple
         except ImportError:  # pragma: no cover
             pass
         else:
-            from .stubs.tornado_stubs import VCRAsyncHTTPClient
+            from .stubs.tornado_stubs import vcr_fetch_impl
-            from .stubs.tornado_stubs import VCRSimpleAsyncHTTPClient
 
-            yield http, 'AsyncHTTPClient', VCRAsyncHTTPClient
+            new_fetch_impl = vcr_fetch_impl(
-            yield simple, 'SimpleAsyncHTTPClient', VCRSimpleAsyncHTTPClient
+                self._cassette, _SimpleAsyncHTTPClient_fetch_impl
+            )
+            yield simple.SimpleAsyncHTTPClient, 'fetch_impl', new_fetch_impl
         try:
             import tornado.curl_httpclient as curl
         except ImportError:  # pragma: no cover
             pass
         else:
-            from .stubs.tornado_stubs import VCRCurlAsyncHTTPClient
+            from .stubs.tornado_stubs import vcr_fetch_impl
-            yield curl, 'CurlAsyncHTTPClient', VCRCurlAsyncHTTPClient
+
+            new_fetch_impl = vcr_fetch_impl(
+                self._cassette, _CurlAsyncHTTPClient_fetch_impl
+            )
+            yield curl.CurlAsyncHTTPClient, 'fetch_impl', new_fetch_impl
 
     def _urllib3_patchers(self, cpool, stubs):
         http_connection_remover = ConnectionRemover(
@@ -362,19 +366,25 @@ def reset_patchers():
                                 _CertValidatingHTTPSConnection)
 
     try:
-        import tornado.httpclient as http
         import tornado.simple_httpclient as simple
     except ImportError:  # pragma: no cover
         pass
     else:
-        yield mock.patch.object(http, 'AsyncHTTPClient', _AsyncHTTPClient)
+        yield mock.patch.object(
-        yield mock.patch.object(simple, 'SimpleAsyncHTTPClient', _SimpleAsyncHTTPClient)
+            simple.SimpleAsyncHTTPClient,
+            'fetch_impl',
+            _SimpleAsyncHTTPClient_fetch_impl,
+        )
     try:
         import tornado.curl_httpclient as curl
     except ImportError:  # pragma: no cover
         pass
     else:
-        yield mock.patch.object(curl, 'CurlAsyncHTTPClient', _CurlAsyncHTTPClient)
+        yield mock.patch.object(
+            curl.CurlAsyncHTTPClient,
+            'fetch_impl', 
+            _CurlAsyncHTTPClient_fetch_impl,
+        )
 
 
 @contextlib.contextmanager

vcr/stubs/tornado_stubs.py

@@ -1,48 +1,20 @@
 '''Stubs for tornado HTTP clients'''
 from __future__ import absolute_import
 
+import functools
 from six import BytesIO
 
 from tornado import httputil
-from tornado.httpclient import AsyncHTTPClient
 from tornado.httpclient import HTTPResponse
-from tornado.simple_httpclient import SimpleAsyncHTTPClient
 
 from vcr.errors import CannotOverwriteExistingCassetteException
 from vcr.request import Request
 
 
-class _VCRAsyncClient(object):
+def vcr_fetch_impl(cassette, real_fetch_impl):
-    cassette = None
 
-    def __new__(cls, *args, **kwargs):
+    @functools.wraps(real_fetch_impl)
-        from vcr.patch import force_reset
+    def new_fetch_impl(self, request, callback):
-        with force_reset():
-            return super(_VCRAsyncClient, cls).__new__(cls, *args, **kwargs)
-
-    def initialize(self, *args, **kwargs):
-        from vcr.patch import force_reset
-        with force_reset():
-            self.real_client = self._baseclass(*args, **kwargs)
-
-    @property
-    def io_loop(self):
-        return self.real_client.io_loop
-
-    @property
-    def _closed(self):
-        return self.real_client._closed
-
-    @property
-    def defaults(self):
-        return self.real_client.defaults
-
-    def close(self):
-        from vcr.patch import force_reset
-        with force_reset():
-            self.real_client.close()
-
-    def fetch_impl(self, request, callback):
         headers = dict(request.headers)
         if request.user_agent:
             headers.setdefault('User-Agent', request.user_agent)
@@ -74,8 +46,8 @@ class _VCRAsyncClient(object):
             headers,
         )
 
-        if self.cassette.can_play_response_for(vcr_request):
+        if cassette.can_play_response_for(vcr_request):
-            vcr_response = self.cassette.play_response(vcr_request)
+            vcr_response = cassette.play_response(vcr_request)
             headers = httputil.HTTPHeaders()
 
             recorded_headers = vcr_response['headers']
@@ -93,7 +65,7 @@ class _VCRAsyncClient(object):
             )
             return callback(response)
         else:
-            if self.cassette.write_protected and self.cassette.filter_request(
+            if cassette.write_protected and cassette.filter_request(
                 vcr_request
             ):
                 response = HTTPResponse(
@@ -103,8 +75,7 @@ class _VCRAsyncClient(object):
                         "No match for the request (%r) was found. "
                         "Can't overwrite existing cassette (%r) in "
                         "your current record mode (%r)."
-                        % (vcr_request, self.cassette._path,
+                        % (vcr_request, cassette._path, cassette.record_mode)
-                           self.cassette.record_mode)
                     ),
                 )
                 return callback(response)
@@ -123,26 +94,9 @@ class _VCRAsyncClient(object):
                     'headers': headers,
                     'body': {'string': response.body},
                 }
-                self.cassette.append(vcr_request, vcr_response)
+                cassette.append(vcr_request, vcr_response)
                 return callback(response)
 
-            from vcr.patch import force_reset
+            real_fetch_impl(self, request, new_callback)
-            with force_reset():
-                self.real_client.fetch_impl(request, new_callback)
 
-
+    return new_fetch_impl
-class VCRAsyncHTTPClient(_VCRAsyncClient, AsyncHTTPClient):
-    _baseclass = AsyncHTTPClient
-
-
-class VCRSimpleAsyncHTTPClient(_VCRAsyncClient, SimpleAsyncHTTPClient):
-    _baseclass = SimpleAsyncHTTPClient
-
-
-try:
-    from tornado.curl_httpclient import CurlAsyncHTTPClient
-except ImportError:  # pragma: no cover
-    VCRCurlAsyncHTTPClient = None
-else:
-    class VCRCurlAsyncHTTPClient(_VCRAsyncClient, CurlAsyncHTTPClient):
-        _baseclass = CurlAsyncHTTPClient