Merge pull request #292 from j-funk/master

Allow injection of persistence methods

docs/advanced.rst

@@ -122,6 +122,27 @@ Finally, register your method with VCR to use your new request matcher.
     with my_vcr.use_cassette('test.yml'):
         # your http here
 
+Register your own cassette persister
+------------------------------------
+
+Create your own persistence class, see the :ref:`persister_example`.
+
+Your custom persister must implement both ``load_cassette`` and ``save_cassette``
+methods.  The ``load_cassette`` method must return a deserialized cassette or raise
+ ``ValueError`` if no cassette is found.
+
+Once the persister class is defined, register with VCR like so...
+
+.. code:: python
+
+    import vcr
+    my_vcr = vcr.VCR()
+
+    class CustomerPersister(object):
+        # implement Persister methods...
+
+    my_vcr.register_persister(CustomPersister)
+
 Filter sensitive data from the request
 --------------------------------------
 

tests/integration/test_register_persister.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+'''Tests for cassettes with custom persistence'''
+
+# External imports
+import os
+from six.moves.urllib.request import urlopen
+
+# Internal imports
+import vcr
+from vcr.persisters.filesystem import FilesystemPersister
+
+
+def test_save_cassette_with_custom_persister(tmpdir, httpbin):
+    '''Ensure you can save a cassette using custom persister'''
+    my_vcr = vcr.VCR()
+    my_vcr.register_persister(FilesystemPersister)
+
+    # Check to make sure directory doesnt exist
+    assert not os.path.exists(str(tmpdir.join('nonexistent')))
+
+    # Run VCR to create dir and cassette file using new save_cassette callback
+    with my_vcr.use_cassette(str(tmpdir.join('nonexistent', 'cassette.yml'))):
+        urlopen(httpbin.url).read()
+
+    # Callback should have made the file and the directory
+    assert os.path.exists(str(tmpdir.join('nonexistent', 'cassette.yml')))
+
+
+def test_load_cassette_with_custom_persister(tmpdir, httpbin):
+    '''
+    Ensure you can load a cassette using custom persister
+    '''
+    my_vcr = vcr.VCR()
+    my_vcr.register_persister(FilesystemPersister)
+
+    test_fixture = str(tmpdir.join('synopsis.json'))
+
+    with my_vcr.use_cassette(test_fixture, serializer='json'):
+        response = urlopen(httpbin.url).read()
+        assert b'difficult sometimes' in response

tests/unit/test_cassettes.py

@@ -83,7 +83,8 @@ def make_get_request():
 
 
 @mock.patch('vcr.cassette.requests_match', return_value=True)
-@mock.patch('vcr.cassette.load_cassette', lambda *args, **kwargs: (('foo',), (mock.MagicMock(),)))
+@mock.patch('vcr.cassette.FilesystemPersister.load_cassette',
+            classmethod(lambda *args, **kwargs: (('foo',), (mock.MagicMock(),))))
 @mock.patch('vcr.cassette.Cassette.can_play_response_for', return_value=True)
 @mock.patch('vcr.stubs.VCRHTTPResponse')
 def test_function_decorated_with_use_cassette_can_be_invoked_multiple_times(*args):

tests/unit/test_persist.py

@@ -1,6 +1,6 @@
 import pytest
 
-import vcr.persist
+from vcr.persisters.filesystem import FilesystemPersister
 from vcr.serializers import jsonserializer, yamlserializer
 
 
@@ -10,7 +10,7 @@ from vcr.serializers import jsonserializer, yamlserializer
 ])
 def test_load_cassette_with_old_cassettes(cassette_path, serializer):
     with pytest.raises(ValueError) as excinfo:
-        vcr.persist.load_cassette(cassette_path, serializer)
+        FilesystemPersister.load_cassette(cassette_path, serializer)
     assert "run the migration script" in excinfo.exconly()
 
 
@@ -20,5 +20,5 @@ def test_load_cassette_with_old_cassettes(cassette_path, serializer):
 ])
 def test_load_cassette_with_invalid_cassettes(cassette_path, serializer):
     with pytest.raises(Exception) as excinfo:
-        vcr.persist.load_cassette(cassette_path, serializer)
+        FilesystemPersister.load_cassette(cassette_path, serializer)
     assert "run the migration script" not in excinfo.exconly()

tests/unit/test_vcr.py

@@ -94,7 +94,7 @@ def test_vcr_before_record_response_iterable():
     response = object()  # just can't be None
 
     # Prevent actually saving the cassette
-    with mock.patch('vcr.cassette.save_cassette'):
+    with mock.patch('vcr.cassette.FilesystemPersister.save_cassette'):
 
         # Baseline: non-iterable before_record_response should work
         mock_filter = mock.Mock()
@@ -118,7 +118,7 @@ def test_before_record_response_as_filter():
     response = object()  # just can't be None
 
     # Prevent actually saving the cassette
-    with mock.patch('vcr.cassette.save_cassette'):
+    with mock.patch('vcr.cassette.FilesystemPersister.save_cassette'):
 
         filter_all = mock.Mock(return_value=None)
         vcr = VCR(before_record_response=filter_all)
@@ -132,7 +132,7 @@ def test_vcr_path_transformer():
     # Regression test for #199
 
     # Prevent actually saving the cassette
-    with mock.patch('vcr.cassette.save_cassette'):
+    with mock.patch('vcr.cassette.FilesystemPersister.save_cassette'):
 
         # Baseline: path should be unchanged
         vcr = VCR()

vcr/cassette.py

@@ -8,8 +8,8 @@ from .compat import contextlib, collections
 from .errors import UnhandledHTTPRequestError
 from .matchers import requests_match, uri, method
 from .patch import CassettePatcherBuilder
-from .persist import load_cassette, save_cassette
 from .serializers import yamlserializer
+from .persisters.filesystem import FilesystemPersister
 from .util import partition_dict
 
 
@@ -163,11 +163,11 @@ class Cassette(object):
     def use(cls, **kwargs):
         return CassetteContextDecorator.from_args(cls, **kwargs)
 
-    def __init__(self, path, serializer=yamlserializer, record_mode='once',
+    def __init__(self, path, serializer=yamlserializer, persister=FilesystemPersister, record_mode='once',
                  match_on=(uri, method), before_record_request=None,
                  before_record_response=None, custom_patches=(),
                  inject=False):
-
+        self._persister = persister
         self._path = path
         self._serializer = serializer
         self._match_on = match_on
@@ -271,24 +271,24 @@ class Cassette(object):
 
     def _save(self, force=False):
         if force or self.dirty:
-            save_cassette(
+            self._persister.save_cassette(
                 self._path,
                 self._as_dict(),
-                serializer=self._serializer
+                serializer=self._serializer,
             )
             self.dirty = False
 
     def _load(self):
         try:
-            requests, responses = load_cassette(
+            requests, responses = self._persister.load_cassette(
                 self._path,
-                serializer=self._serializer
+                serializer=self._serializer,
             )
             for request, response in zip(requests, responses):
                 self.append(request, response)
             self.dirty = False
             self.rewound = True
-        except IOError:
+        except ValueError:
             pass
 
     def __str__(self):

vcr/config.py

@@ -9,6 +9,7 @@ import six
 from .compat import collections
 from .cassette import Cassette
 from .serializers import yamlserializer, jsonserializer
+from .persisters.filesystem import FilesystemPersister
 from .util import compose, auto_decorate
 from . import matchers
 from . import filters
@@ -57,6 +58,7 @@ class VCR(object):
             'raw_body': matchers.raw_body,
             'body': matchers.body,
         }
+        self.persister = FilesystemPersister
         self.record_mode = record_mode
         self.filter_headers = filter_headers
         self.filter_query_parameters = filter_query_parameters
@@ -270,6 +272,10 @@ class VCR(object):
     def register_matcher(self, name, matcher):
         self.matchers[name] = matcher
 
+    def register_persister(self, persister):
+        # Singleton, no name required
+        self.persister = persister
+
     def test_case(self, predicate=None):
         predicate = predicate or self.is_test_method
         return six.with_metaclass(auto_decorate(self.use_cassette, predicate))

vcr/persist.py

@@ -1,14 +0,0 @@
-from .persisters.filesystem import FilesystemPersister
-from .serialize import serialize, deserialize
-
-
-def load_cassette(cassette_path, serializer):
-    with open(cassette_path) as f:
-        cassette_content = f.read()
-        cassette = deserialize(cassette_content, serializer)
-        return cassette
-
-
-def save_cassette(cassette_path, cassette_dict, serializer):
-    data = serialize(cassette_dict, serializer)
-    FilesystemPersister.write(cassette_path, data)

vcr/persisters/filesystem.py

@@ -1,9 +1,24 @@
+# .. _persister_example:
+
 import os
+from ..serialize import serialize, deserialize
 
 
 class FilesystemPersister(object):
+
     @classmethod
-    def write(cls, cassette_path, data):
+    def load_cassette(cls, cassette_path, serializer):
+        try:
+            with open(cassette_path) as f:
+                cassette_content = f.read()
+        except IOError:
+            raise ValueError('Cassette not found.')
+        cassette = deserialize(cassette_content, serializer)
+        return cassette
+
+    @staticmethod
+    def save_cassette(cassette_path, cassette_dict, serializer):
+        data = serialize(cassette_dict, serializer)
         dirname, filename = os.path.split(cassette_path)
         if dirname and not os.path.exists(dirname):
             os.makedirs(dirname)