
#### FIX: Do not use client lastReadMessageId when fetching channel messages We had an issue where the following happened: 1. User opened channel and saw the last message, and we set the lastReadMessageId on the server and the client 2. User navigated to another channel 3. Another user deleted the message in the original channel 4. The first user navigated back to the original channel before the MessageBus event for the deleted message arrived, and got a 404 error because we were sending the deleted lastReadMessageId as target_message_id to the channel controller. Instead of this which is a bit flaky and is hard to cover all the issues for, instead we can pass a fetch_from_last_read boolean param to the channels controller, and just get the user's last_read_message_id straight from the database to use for the target_message_id. This gets rid of any sources of race conditions or lack of updates from MessageBus. #### FIX: Include missing memberships for thread tracking publish When we publish the channel/message tracking state for a user and that message was a thread reply the publisher was erroring because we were not telling Chat::TrackingStateReportQuery to return missing memberships (which have zeroed out unread counts) as well, which is what we do for the channel tracking state here. Also just make sure that the TrackingStateReport does not error when passed an ID it doesn't have data for.

Discourse is the 100% open source discussion platform built for the next decade of the Internet. Use it as a:
- mailing list
- discussion forum
- long-form chat room
To learn more about the philosophy and goals of the project, visit discourse.org.
Screenshots

Browse lots more notable Discourse instances.
Development
To get your environment setup, follow the community setup guide for your operating system.
- If you're on macOS, try the macOS development guide.
- If you're on Ubuntu, try the Ubuntu development guide.
- If you're on Windows, try the Windows 10 development guide.
If you're familiar with how Rails works and are comfortable setting up your own environment, you can also try out the Discourse Advanced Developer Guide, which is aimed primarily at Ubuntu and macOS environments.
Before you get started, ensure you have the following minimum versions: Ruby 3.2+, PostgreSQL 13, Redis 7. If you're having trouble, please see our TROUBLESHOOTING GUIDE first!
Setting up Discourse
If you want to set up a Discourse forum for production use, see our Discourse Install Guide.
If you're looking for business class hosting, see discourse.org/buy.
Requirements
Discourse is built for the next 10 years of the Internet, so our requirements are high.
Discourse supports the latest, stable releases of all major browsers and platforms:
Browsers | Tablets | Phones |
---|---|---|
Apple Safari | iPadOS | iOS |
Google Chrome | Android | Android |
Microsoft Edge | ||
Mozilla Firefox |
Additionally, we aim to support Safari on iOS 15.7+.
Built With
- Ruby on Rails — Our back end API is a Rails app. It responds to requests RESTfully in JSON.
- Ember.js — Our front end is an Ember.js app that communicates with the Rails API.
- PostgreSQL — Our main data store is in Postgres.
- Redis — We use Redis as a cache and for transient data.
- BrowserStack — We use BrowserStack to test on real devices and browsers.
Plus lots of Ruby Gems, a complete list of which is at /main/Gemfile.
Contributing
Discourse is 100% free and open source. We encourage and support an active, healthy community that accepts contributions from the public – including you!
Before contributing to Discourse:
- Please read the complete mission statements on discourse.org. Yes we actually believe this stuff; you should too.
- Read and sign the Electronic Discourse Forums Contribution License Agreement.
- Dig into CONTRIBUTING.MD, which covers submitting bugs, requesting new features, preparing your code for a pull request, etc.
- Always strive to collaborate with mutual respect.
- Not sure what to work on? We've got some ideas.
We look forward to seeing your pull requests!
Security
We take security very seriously at Discourse; all our code is 100% open source and peer reviewed. Please read our security guide for an overview of security measures in Discourse, or if you wish to report a security issue.
The Discourse Team
The original Discourse code contributors can be found in AUTHORS.MD. For a complete list of the many individuals that contributed to the design and implementation of Discourse, please refer to the official Discourse blog and GitHub's list of contributors.
Copyright / License
Copyright 2014 - 2023 Civilized Discourse Construction Kit, Inc.
Licensed under the GNU General Public License Version 2.0 (or later); you may not use this work except in compliance with the License. You may obtain a copy of the License in the LICENSE file, or at:
https://www.gnu.org/licenses/old-licenses/gpl-2.0.txt
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
Discourse logo and “Discourse Forum” ®, Civilized Discourse Construction Kit, Inc.
Accessibility
To guide our ongoing effort to build accessible software we follow the W3C’s Web Content Accessibility Guidelines (WCAG). If you'd like to report an accessibility issue that makes it difficult for you to use Discourse, email accessibility@discourse.org. For more information visit discourse.org/accessibility.
Dedication
Discourse is built with love, Internet style.