e6eace307e
Clearing the sessions inside the transaction makes Zulip vulnerable to a narrow window where the deleted session has not yet been committed, but has been removed from the memcached cache. During this window, a request with the session-id which has just been deleted can successfully re-fill the memcached cache, as the in-database delete is not yet committed, and thus not yet visible. After the delete transaction commits, the cache will be left with a cached session, which allows further site access until it expires (after SESSION_COOKIE_AGE seconds), is ejected from the cache due to memory pressure, or the server is upgraded. Move the session deletion outside of the transaction. Because the testsuite runs inside of a transaction, it is impossible to test this is CI; the testsuite uses the non-caching `django.contrib.sessions.backends.db` backend, regardless. The test added in this commit thus does not fail before this commit; it is merely a base expression that the session should be deleted somehow, and does not exercise the assert added in the previous commit.
Zulip overview
Zulip is a powerful, open source group chat application that combines the immediacy of real-time chat with the productivity benefits of threaded conversations. Zulip is used by open source projects, Fortune 500 companies, large standards bodies, and others who need a real-time chat system that allows users to easily process hundreds or thousands of messages a day. With over 700 contributors merging over 500 commits a month, Zulip is also the largest and fastest growing open source group chat project.
Getting started
Click on the appropriate link below. If nothing seems to apply, join us on the Zulip community server and tell us what's up!
You might be interested in:
-
Contributing code. Check out our guide for new contributors to get started. Zulip prides itself on maintaining a clean and well-tested codebase, and a stock of hundreds of beginner-friendly issues.
-
Contributing non-code. Report an issue, translate Zulip into your language, write for the Zulip blog, or give us feedback. We would love to hear from you, even if you're just trying the product out.
-
Supporting Zulip. Advocate for your organization to use Zulip, become a sponsor, write a review in the mobile app stores, or upvote Zulip on product comparison sites.
-
Checking Zulip out. The best way to see Zulip in action is to drop by the Zulip community server. We also recommend reading Zulip for open source, Zulip for companies, or Zulip for working groups and part time communities.
-
Running a Zulip server. Use a preconfigured DigitalOcean droplet, install Zulip directly, or use Zulip's experimental Docker image. Commercial support is available; see https://zulip.com/plans for details.
-
Using Zulip without setting up a server. https://zulip.com offers free and commercial hosting, including providing our paid plan for free to fellow open source projects.
-
Participating in outreach programs like Google Summer of Code.
You may also be interested in reading our blog or following us on Twitter. Zulip is distributed under the Apache 2.0 license.