Discourse supports replying and starting new topics via email only through checking an external mailbox via POP3. This little plugin accepts incoming email through an http endpoint.
This plugin only supports Mailgun, adapting this to work with other services is trivial and it is left as an exercise to the reader.
- Make sure your Discourse instance works correctly, especially make sure it can deliver emails. It's not actually required for the plugin to work but it is required by Discourse anyway.
- Follow the istructions to install a Discourse plugin. Don't forget to rebuild your instance.
- In Settings > Email, tick "reply by email enabled" and set "reply by email address" to something like "replies+%{reply_key}@example.com" where example.com has MX records pointing to Mailgun.
- In the admin panel go to Plugins > mailgun > Settings, tick "Mailgun plugin enabled" and copy the API key for "example.com" above in the "Mailgun API key" box.
- At Mailgun, set up a route for "example.com" with a filter that matches the
above address and with action
forward("http://your.discourse.instance/mailgun/mime"). In principle your Discourse instance doesn't need to live on the same domain you use for incoming email. If you have TLS enable you can try to use https here, I don't know, I haven't tried yet. - Do a couple of tests and let me know if it works.
Keep an eye on Mailgun logs and on Discourse error log at /logs too.
The plugin installs a route /mailgun/mime that accepts POST requests. The
controller:
- Checks that the plugin is enabled.
- Checks the request has a valid authenticity token.
- Call the same procedure Discourse would use to process emails collected from the external mailbox.
In case 1. or 2. fail, the controller will reply with status 406 Not Acceptable. This instructs Mailgun to not try to re-deliver the same message again. If a message fails to process, the controller still replies with 200 OK, as, in the end, the message was successfully delivered to the Discourse instance.
Mailgun documentation for reference.
This is the first time I write something with Rails. If what you see is hurting your eyes, please send a pull request!