From 8f5d7302acb7f6d15ba7051df7fd7fda7375a29e Mon Sep 17 00:00:00 2001 From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com> Date: Wed, 15 Jan 2020 15:58:55 +0000 Subject: [PATCH] Implement RedirectException (#6687) Allow REST endpoint implemnentations to raise a RedirectException, which will redirect the user's browser to a given location. --- changelog.d/6687.misc | 1 + synapse/api/errors.py | 27 ++++++++++++++- synapse/http/server.py | 13 ++++--- tests/test_server.py | 79 ++++++++++++++++++++++++++++++++++++++++-- 4 files changed, 113 insertions(+), 7 deletions(-) create mode 100644 changelog.d/6687.misc 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): """