Merge lp:~pedronis/u1db/cors-middleware into lp:u1db

[Samuele Pedroni]

add CORS middleware

- CORS middleware
- tweak to allow passing all tests with u1db.js under different origin conditions

testing beyond unit tests/trying:

get lp:~pedronis/u1db/u1db-js-different-origin

run in it:

TEST_BROWSER=firefox PYTHONPATH=../cors-middleware/:. unit2 tests.test_bridged

atm there should be only 1 unrelated failure there

[Samuele Pedroni (pedronis)]

confirmed working against: chromium, safari, and firefox

[Lucio Torre (lucio.torre)]

code looks sane.

review: Approve

[Stuart Langridge (sil)]

Serving correct CORS headers, and u1db.js will sync with a u1db-serve which provides these headers.

review: Approve

=== added file 'u1db/remote/cors_middleware.py'
--- u1db/remote/cors_middleware.py	1970-01-01 00:00:00 +0000
+++ u1db/remote/cors_middleware.py	2012-10-10 16:31:57 +0000
@@ -0,0 +1,42 @@
+# Copyright 2012 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+"""U1DB Cross-Origin Resource Sharing WSGI middleware."""
+
+
+class CORSMiddleware(object):
+    """U1DB Cross-Origin Resource Sharing WSGI middleware."""
+
+    def __init__(self, app, accept_cors_connections):
+        self.origins = ' '.join(accept_cors_connections)
+        self.app = app
+
+    def _cors_headers(self):
+        return [('access-control-allow-origin', self.origins),
+                ('access-control-allow-headers',
+                 'authorization, content-type'),
+                ('access-control-allow-methods',
+                 'GET, POST, PUT, DELETE, OPTIONS')]
+
+    def __call__(self, environ, start_response):
+        def wrap_start_response(status, headers, exc_info=None):
+            headers += self._cors_headers()
+            return start_response(status, headers, exc_info)
+
+        if environ['REQUEST_METHOD'].lower() == 'options':
+            wrap_start_response("200 OK", [('content-type', 'text/plain')])
+            return ['']
+
+        return self.app(environ, wrap_start_response)
 
=== added file 'u1db/tests/test_cors_middleware.py'
--- u1db/tests/test_cors_middleware.py	1970-01-01 00:00:00 +0000
+++ u1db/tests/test_cors_middleware.py	2012-10-10 16:31:57 +0000
@@ -0,0 +1,66 @@
+# Copyright 2012 Canonical Ltd.
+#
+# This file is part of u1db.
+#
+# u1db is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# u1db is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with u1db.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Test CORS wsgi middleware"""
+import paste.fixture
+
+from u1db import tests
+
+from u1db.remote.cors_middleware import CORSMiddleware
+
+
+class TestCORSMiddleware(tests.TestCase):
+
+    def setUp(self):
+        super(TestCORSMiddleware, self).setUp()
+
+    def app(self, accept_cors_connections):
+
+        def base_app(environ, start_response):
+            start_response("200 OK", [("content-type", "application/json")])
+            return ['{}']
+
+        return paste.fixture.TestApp(CORSMiddleware(base_app,
+                                                    accept_cors_connections))
+
+    def _check_cors_headers(self, resp, expect):
+        self.assertEqual(expect, resp.header('access-control-allow-origin'))
+        self.assertEqual("GET, POST, PUT, DELETE, OPTIONS",
+                         resp.header('access-control-allow-methods'))
+        self.assertEqual("authorization, content-type",
+                         resp.header('access-control-allow-headers'))
+
+    def test_options(self):
+        app = self.app(['*'])
+        resp = app._gen_request('OPTIONS', '/')
+        self.assertEqual(200, resp.status)
+        self._check_cors_headers(resp, '*')
+        self.assertEqual('', resp.body)
+
+        app = self.app(['http://bar.example', 'http://foo.example'])
+        resp = app._gen_request('OPTIONS', '/db1')
+        self.assertEqual(200, resp.status)
+        self._check_cors_headers(resp, 'http://bar.example http://foo.example')
+        self.assertEqual('', resp.body)
+
+    def test_pass_through(self):
+        app = self.app(['*'])
+        resp = app.get('/db0')
+        self.assertEqual(200, resp.status)
+        self._check_cors_headers(resp, '*')
+        self.assertEqual('application/json', resp.header('content-type'))
+        self.assertEqual('{}', resp.body)
+
 
=== modified file 'u1db/tests/test_remote_sync_target.py'
--- u1db/tests/test_remote_sync_target.py	2012-09-25 20:04:08 +0000
+++ u1db/tests/test_remote_sync_target.py	2012-10-10 16:31:57 +0000
@@ -177,9 +177,13 @@
         self.assertGetDoc(
             db, 'doc-here', 'replica:1', '{"value": "here"}', False)
 
+    failure_scenario_exceptions = (Exception, errors.HTTPError)
+
     def test_sync_exchange_send_failure_and_retry_scenario(self):
         self.startServer()
 
+        server_side_exc, client_side_exc = self.failure_scenario_exceptions
+
         def blackhole_getstderr(inst):
             return cStringIO.StringIO()
 
@@ -193,7 +197,7 @@
                                   replica_uid=None, replica_gen=None,
                                   replica_trans_id=None):
             if doc.doc_id in trigger_ids:
-                raise Exception
+                raise server_side_exc
             return _put_doc_if_newer(doc, save_conflict=save_conflict,
                 replica_uid=replica_uid, replica_gen=replica_gen,
                 replica_trans_id=replica_trans_id)
@@ -209,7 +213,7 @@
         doc2 = self.make_document('doc-here2', 'replica:1',
                                   '{"value": "here2"}')
         self.assertRaises(
-            errors.HTTPError,
+            client_side_exc,
             remote_target.sync_exchange,
             [(doc1, 10, 'T-sid'), (doc2, 11, 'T-sud')],
             'replica', last_known_generation=0, last_known_trans_id=None,