Provide interfaces for Plugins exposing an API

[jaudriga]

audriga/roundcube-jmap is a plugin that exposes a JMAP API focusing on Contacts and Calendars within Roundcube. Currently, this involves duplicating some of Roundcube's index.php code, which is not ideal for maintenance and compatibility.

It would be helpful if Roundcube could provide some interfaces or hooks for plugins that want to expose an API. Presently, our implementation involves duplicating the following from RC's index.php:

• Including environment via program/include/iniset.php .
• Authentication by calling the authenticate hook and subsequently rcmail->login().

Including the iniset file might already be sufficient for such use cases. However, passing basic-auth credentials to the authenticate hook and the subsequent login is currently not ideal.

One requirement for us would be that this is also compatible with Roudcube installations in cPanel, which might pose additional requirements on authentication compared to vanilla Roundcube. At least, when we tested against RC in cPanel we ran into authentication issues when not using any hooks. Especially the authentication hook might be important.

Additional Information:

All code that audriga/roundcube-jmap duplicated from the index.php can be seen in bridge.php.

This issue is related to the discussions in #5918.

Another example of a plugin that provides an API is freebusy, which you can find here: https://git.kolab.org/source/freebusy/. My understanding is that it seem to differ from our approach by:

• avoiding authenticate hook and calling rcube_imap->connect() directly instead
• avoiding reusing progam/include/iniset.php and setting necessary env vars manually instead:

define('RCUBE_INSTALL_PATH', '../../');
define('RCUBE_CONFIG_DIR',   RCUBE_INSTALL_PATH . '/config/');
define('RCUBE_PLUGINS_DIR',  RCUBE_INSTALL_PATH . '/lib/plugins/');
...

[alecpl]

There's the startup hook. I'm not sure what else would you need. Provide a pull request.

[jaudriga]

I opened up a #9418 . I hope this makes it clearer what I meant initially. The JMAP RC Plugin is not a plugin in a strict sense, it follows a similar approach as Kolab's FreeBusy plugin, but uses the rcmail class to reuse authentication logic.