diff --git a/changelog.d/6687.misc b/changelog.d/6687.misc
new file mode 100644
index 0000000000..deb0454602
--- /dev/null
+++ b/changelog.d/6687.misc
@@ -0,0 +1 @@
+Allow REST endpoint implementations to raise a RedirectException, which will redirect the user's browser to a given location.
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 9e9844b47c..1c9456e583 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -17,13 +17,15 @@
"""Contains exceptions and error codes."""
import logging
-from typing import Dict
+from typing import Dict, List
from six import iteritems
from six.moves import http_client
from canonicaljson import json
+from twisted.web import http
+
logger = logging.getLogger(__name__)
@@ -80,6 +82,29 @@ class CodeMessageException(RuntimeError):
self.msg = msg
+class RedirectException(CodeMessageException):
+ """A pseudo-error indicating that we want to redirect the client to a different
+ location
+
+ Attributes:
+ cookies: a list of set-cookies values to add to the response. For example:
+ b"sessionId=a3fWa; Expires=Wed, 21 Oct 2015 07:28:00 GMT"
+ """
+
+ def __init__(self, location: bytes, http_code: int = http.FOUND):
+ """
+
+ Args:
+ location: the URI to redirect to
+ http_code: the HTTP response code
+ """
+ msg = "Redirect to %s" % (location.decode("utf-8"),)
+ super().__init__(code=http_code, msg=msg)
+ self.location = location
+
+ self.cookies = [] # type: List[bytes]
+
+
class SynapseError(CodeMessageException):
"""A base exception type for matrix errors which have an errcode and error
message (as well as an HTTP status code).
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 943d12c907..04bc2385a2 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -14,8 +14,8 @@
# See the License for the specific language governing permissions and
# limitations under the License.
-import cgi
import collections
+import html
import http.client
import logging
import types
@@ -36,6 +36,7 @@ import synapse.metrics
from synapse.api.errors import (
CodeMessageException,
Codes,
+ RedirectException,
SynapseError,
UnrecognizedRequestError,
)
@@ -153,14 +154,18 @@ def _return_html_error(f, request):
Args:
f (twisted.python.failure.Failure):
- request (twisted.web.iweb.IRequest):
+ request (twisted.web.server.Request):
"""
if f.check(CodeMessageException):
cme = f.value
code = cme.code
msg = cme.msg
- if isinstance(cme, SynapseError):
+ if isinstance(cme, RedirectException):
+ logger.info("%s redirect to %s", request, cme.location)
+ request.setHeader(b"location", cme.location)
+ request.cookies.extend(cme.cookies)
+ elif isinstance(cme, SynapseError):
logger.info("%s SynapseError: %s - %s", request, code, msg)
else:
logger.error(
@@ -178,7 +183,7 @@ def _return_html_error(f, request):
exc_info=(f.type, f.value, f.getTracebackObject()),
)
- body = HTML_ERROR_TEMPLATE.format(code=code, msg=cgi.escape(msg)).encode("utf-8")
+ body = HTML_ERROR_TEMPLATE.format(code=code, msg=html.escape(msg)).encode("utf-8")
request.setResponseCode(code)
request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
request.setHeader(b"Content-Length", b"%i" % (len(body),))
diff --git a/tests/test_server.py b/tests/test_server.py
index 98fef21d55..0d57eed268 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -23,8 +23,12 @@ from twisted.test.proto_helpers import AccumulatingProtocol
from twisted.web.resource import Resource
from twisted.web.server import NOT_DONE_YET
-from synapse.api.errors import Codes, SynapseError
-from synapse.http.server import JsonResource
+from synapse.api.errors import Codes, RedirectException, SynapseError
+from synapse.http.server import (
+ DirectServeResource,
+ JsonResource,
+ wrap_html_request_handler,
+)
from synapse.http.site import SynapseSite, logger
from synapse.logging.context import make_deferred_yieldable
from synapse.util import Clock
@@ -164,6 +168,77 @@ class JsonResourceTests(unittest.TestCase):
self.assertEqual(channel.json_body["errcode"], "M_UNRECOGNIZED")
+class WrapHtmlRequestHandlerTests(unittest.TestCase):
+ class TestResource(DirectServeResource):
+ callback = None
+
+ @wrap_html_request_handler
+ async def _async_render_GET(self, request):
+ return await self.callback(request)
+
+ def setUp(self):
+ self.reactor = ThreadedMemoryReactorClock()
+
+ def test_good_response(self):
+ def callback(request):
+ request.write(b"response")
+ request.finish()
+
+ res = WrapHtmlRequestHandlerTests.TestResource()
+ res.callback = callback
+
+ request, channel = make_request(self.reactor, b"GET", b"/path")
+ render(request, res, self.reactor)
+
+ self.assertEqual(channel.result["code"], b"200")
+ body = channel.result["body"]
+ self.assertEqual(body, b"response")
+
+ def test_redirect_exception(self):
+ """
+ If the callback raises a RedirectException, it is turned into a 30x
+ with the right location.
+ """
+
+ def callback(request, **kwargs):
+ raise RedirectException(b"/look/an/eagle", 301)
+
+ res = WrapHtmlRequestHandlerTests.TestResource()
+ res.callback = callback
+
+ request, channel = make_request(self.reactor, b"GET", b"/path")
+ render(request, res, self.reactor)
+
+ self.assertEqual(channel.result["code"], b"301")
+ headers = channel.result["headers"]
+ location_headers = [v for k, v in headers if k == b"Location"]
+ self.assertEqual(location_headers, [b"/look/an/eagle"])
+
+ def test_redirect_exception_with_cookie(self):
+ """
+ If the callback raises a RedirectException which sets a cookie, that is
+ returned too
+ """
+
+ def callback(request, **kwargs):
+ e = RedirectException(b"/no/over/there", 304)
+ e.cookies.append(b"session=yespls")
+ raise e
+
+ res = WrapHtmlRequestHandlerTests.TestResource()
+ res.callback = callback
+
+ request, channel = make_request(self.reactor, b"GET", b"/path")
+ render(request, res, self.reactor)
+
+ self.assertEqual(channel.result["code"], b"304")
+ headers = channel.result["headers"]
+ location_headers = [v for k, v in headers if k == b"Location"]
+ self.assertEqual(location_headers, [b"/no/over/there"])
+ cookies_headers = [v for k, v in headers if k == b"Set-Cookie"]
+ self.assertEqual(cookies_headers, [b"session=yespls"])
+
+
class SiteTestCase(unittest.HomeserverTestCase):
def test_lose_connection(self):
"""
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