Filter Sensitive Data From Requests

Add the ability to filter out sensitive data, using one of three
methods: from headers, from a query string, and by using a custom
callback to modify the request.

Closes #67

README.md

@@ -255,6 +255,49 @@ with my_vcr.use_cassette('test.yml'):
 
 ```
 
+## Filter sensitive data from the request
+
+If you are checking your cassettes into source control, and are using some form
+of authentication in your tests, you can filter out that information so it won't
+appear in your cassette files.  There are a few ways to do this:
+
+### Filter information from HTTP Headers
+Use the `filter_headers` configuration option with a list of headers to filter.
+
+```python
+with my_vcr.use_cassette('test.yml', filter_headers=['authorization']):
+    # sensitive HTTP request goes here
+```
+
+### Filter information from HTTP querystring
+Use the `filter_query_parameters` configuration option with a list of query
+parameters to filter.
+
+```python
+with my_vcr.use_cassette('test.yml', filter_query_parameters=['api_key']):
+    requests.get('http://api.com/getdata?api_key=secretstring')
+```
+
+### Custom request filtering
+
+If neither of these covers your use case, you can register a callback that will
+manipulate the HTTP request before adding it to the cassette. Use the
+`before_record` configuration option to so this.  Here is an
+example that will never record requests to the /login endpoint.
+
+```python
+def before_record_cb(request):
+    if request.path != '/login':
+        return request
+
+my_vcr = vcr.VCR(
+    before_record = before_record_cb,
+)
+with my_vcr.use_cassette('test.yml'):
+    # your http code here
+```
+
+
 ## Installation
 
 VCR.py is a package on PyPI, so you can `pip install vcrpy` (first you may need
@@ -321,10 +364,11 @@ matchers didn't match. This can help you with debugging custom matchers.
 
 
 ## Changelog
-  * 1.0.0 (in development) - Bump supported Python3 version to 3.4, fix some
-    bugs with Boto support (thanks @marusich), fix error with URL field
-    capitalization in README (thanks @simon-weber), added some log messages
-    to help with debugging.
+  * 1.0.0 (in development) - Add support for filtering sensitive data from
+    requests, bump supported Python3 version to 3.4, fix some bugs with Boto
+    support (thanks @marusich), fix error with URL field capitalization in
+    README (thanks @simon-weber), added some log messages to help with
+    debugging.
   * 0.7.0: VCR.py now supports Python 3! (thanks @asundg)  Also I refactored
     the stub connections quite a bit to add support for the putrequest and
     putheader calls.  This version also adds support for httplib2 (thanks

tests/integration/test_filter.py

@@ -0,0 +1,68 @@
+import base64
+import pytest
+from six.moves.urllib.request import urlopen, Request
+from six.moves.urllib.error import HTTPError
+import vcr
+
+
+def _request_with_auth(url, username, password):
+    request = Request(url)
+    base64string = base64.b64encode(
+        username.encode('ascii') + b':' + password.encode('ascii')
+    )
+    request.add_header(b"Authorization", b"Basic " + base64string)
+    return urlopen(request)
+
+
+def _find_header(cassette, header):
+    for request in cassette.requests:
+        for k, v in request.headers:
+            if header.lower() == k.lower():
+                return True
+    return False
+
+
+def test_filter_basic_auth(tmpdir):
+    url = 'http://httpbin.org/basic-auth/user/passwd'
+    cass_file = str(tmpdir.join('basic_auth_filter.yaml'))
+    my_vcr = vcr.VCR(match_on = ['url', 'method', 'headers'])
+    # 2 requests, one with auth failure and one with auth success
+    with my_vcr.use_cassette(cass_file, filter_headers=['authorization']):
+        with pytest.raises(HTTPError):
+            resp = _request_with_auth(url, 'user', 'wrongpasswd')
+            assert resp.getcode() == 401
+        resp = _request_with_auth(url, 'user', 'passwd')
+        assert resp.getcode() == 200
+    # make same 2 requests, this time both served from cassette.
+    with my_vcr.use_cassette(cass_file, filter_headers=['authorization']) as cass:
+        with pytest.raises(HTTPError):
+            resp = _request_with_auth(url, 'user', 'wrongpasswd')
+            assert resp.getcode() == 401
+        resp = _request_with_auth(url, 'user', 'passwd')
+        assert resp.getcode() == 200
+        # authorization header should not have been recorded
+        assert not _find_header(cass, 'authorization')
+        assert len(cass) == 2
+
+
+def test_filter_querystring(tmpdir):
+    url = 'http://httpbin.org/?foo=bar'
+    cass_file = str(tmpdir.join('filter_qs.yaml'))
+    with vcr.use_cassette(cass_file, filter_query_parameters=['foo']):
+        urlopen(url)
+    with vcr.use_cassette(cass_file, filter_query_parameters=['foo']) as cass:
+        urlopen(url)
+        assert 'foo' not in cass.requests[0].url
+
+def test_filter_callback(tmpdir):
+    url = 'http://httpbin.org/get'
+    cass_file = str(tmpdir.join('basic_auth_filter.yaml'))
+    def before_record_cb(request):
+        if request.path != '/get':
+            return request
+    my_vcr = vcr.VCR(
+        before_record = before_record_cb,
+    )
+    with my_vcr.use_cassette(cass_file, filter_headers=['authorization']) as cass:
+        urlopen(url)
+        assert len(cass) == 0

tests/unit/test_filters.py

@@ -0,0 +1,28 @@
+import mock
+from vcr.filters import _remove_headers, _remove_query_parameters
+from vcr.request import Request
+
+
+def test_remove_headers():
+    request = mock.Mock(headers=[('hello','goodbye'),('secret','header')])
+    assert _remove_headers(request, ['secret']).headers == frozenset([('hello','goodbye')])
+
+
+def test_remove_headers_empty():
+    request = mock.Mock(headers=[('hello','goodbye'),('secret','header')])
+    assert _remove_headers(request, []).headers == frozenset([('hello','goodbye'),('secret','header')])
+
+
+def test_remove_query_parameters():
+    request = mock.Mock(url='http://g.com/?q=cowboys&w=1')
+    assert _remove_query_parameters(request, ['w']).path == '/?q=cowboys'
+
+
+def test_remove_all_query_parameters():
+    request = mock.Mock(url='http://g.com/?q=cowboys&w=1')
+    assert _remove_query_parameters(request, ['w','q']).path == '/'
+
+
+def test_remove_nonexistent_query_parameters():
+    request = mock.Mock(url='http://g.com/')
+    assert _remove_query_parameters(request, ['w','q']).path == '/'

vcr/cassette.py

@@ -11,6 +11,7 @@ from contextdecorator import ContextDecorator
 # Internal imports
 from .patch import install, reset
 from .persist import load_cassette, save_cassette
+from .filters import filter_request
 from .serializers import yamlserializer
 from .matchers import requests_match, url, method
 from .errors import UnhandledHTTPRequestError
@@ -30,10 +31,17 @@ class Cassette(ContextDecorator):
                  path,
                  serializer=yamlserializer,
                  record_mode='once',
-                 match_on=[url, method]):
+                 match_on=[url, method],
+                 filter_headers=[],
+                 filter_query_parameters=[],
+                 before_record=None,
+                 ):
         self._path = path
         self._serializer = serializer
         self._match_on = match_on
+        self._filter_headers = filter_headers
+        self._filter_query_parameters = filter_query_parameters
+        self._before_record = before_record
 
         # self.data is the list of (req, resp) tuples
         self.data = []
@@ -61,16 +69,40 @@ class Cassette(ContextDecorator):
 
     def append(self, request, response):
         '''Add a request, response pair to this cassette'''
+        request = filter_request(
+            request = request,
+            filter_headers = self._filter_headers,
+            filter_query_parameters = self._filter_query_parameters,
+            before_record = self._before_record
+        )
+        if not request:
+            return
         self.data.append((request, response))
         self.dirty = True
 
+    def _responses(self, request):
+        """
+        internal API, returns an iterator with all responses matching
+        the request.
+        """
+        request = filter_request(
+            request = request,
+            filter_headers = self._filter_headers,
+            filter_query_parameters = self._filter_query_parameters,
+            before_record = self._before_record
+        )
+        if not request:
+            return
+        for index, (stored_request, response) in enumerate(self.data):
+            if requests_match(request, stored_request, self._match_on):
+                yield index, response
+
     def play_response(self, request):
         '''
         Get the response corresponding to a request, but only if it
         hasn't been played back before, and mark it as played
         '''
-        for index, (stored_request, response) in enumerate(self.data):
-            if requests_match(request, stored_request, self._match_on):
+        for index, response in self._responses(request):
             if self.play_counts[index] == 0:
                 self.play_counts[index] += 1
                 return response
@@ -86,9 +118,7 @@ class Cassette(ContextDecorator):
         This function isn't actually used by VCR internally, but is
         provided as an external API.
         '''
-        responses = \
-            [resp for req, resp in self.data if
-                requests_match(req, request, self._match_on)]
+        responses = [response for index, response in self._responses(request)]
 
         if responses:
             return responses
@@ -134,8 +164,7 @@ class Cassette(ContextDecorator):
 
     def __contains__(self, request):
         '''Return whether or not a request has been stored'''
-        for stored_request, response in self.data:
-            if requests_match(stored_request, request, self._match_on):
+        for response in self._responses(request):
             return True
         return False
 

vcr/config.py

@@ -10,6 +10,9 @@ class VCR(object):
                  cassette_library_dir=None,
                  record_mode="once",
                  match_on=['url', 'method'],
+                 filter_headers=[],
+                 filter_query_parameters=[],
+                 before_record=None,
                  ):
         self.serializer = serializer
         self.match_on = match_on
@@ -27,6 +30,9 @@ class VCR(object):
             'body': body,
         }
         self.record_mode = record_mode
+        self.filter_headers = filter_headers
+        self.filter_query_parameters = filter_query_parameters
+        self.before_record = before_record
 
     def _get_serializer(self, serializer_name):
         try:
@@ -65,6 +71,9 @@ class VCR(object):
             "serializer": self._get_serializer(serializer_name),
             "match_on": self._get_matchers(matcher_names),
             "record_mode": kwargs.get('record_mode', self.record_mode),
+            "filter_headers": kwargs.get('filter_headers', self.filter_headers),
+            "filter_query_parameters": kwargs.get('filter_query_parameters', self.filter_query_parameters),
+            "before_record": kwargs.get("before_record", self.before_record),
         }
 
         return Cassette.load(path, **merged_config)

vcr/filters.py

@@ -0,0 +1,40 @@
+from six.moves.urllib.parse import urlparse, parse_qsl, urlunparse, urlencode
+import copy
+
+
+def _remove_headers(request, headers_to_remove):
+    out = []
+    for k, v in request.headers:
+        if k.lower() not in [h.lower() for h in headers_to_remove]:
+            out.append((k, v))
+    request.headers = frozenset(out)
+    return request
+
+
+def _remove_query_parameters(request, query_parameters_to_remove):
+    if not hasattr(request, 'path' or not query_parameters_to_remote):
+        return request
+    url = urlparse(request.url)
+    q = parse_qsl(url.query)
+    q = [(k, v) for k, v in q if k not in query_parameters_to_remove]
+    if q:
+        request.path = url.path + '?' + urlencode(q)
+    else:
+        request.path = url.path
+    return request
+
+
+def filter_request(
+        request,
+        filter_headers,
+        filter_query_parameters,
+        before_record
+        ):
+    request = copy.copy(request)  # don't mutate request object
+    if hasattr(request, 'headers') and filter_headers:
+        request = _remove_headers(request, filter_headers)
+    if filter_query_parameters:
+        request = _remove_query_parameters(request, filter_query_parameters)
+    if before_record:
+        request = before_record(request)
+    return request