Running custom code from a plugin after posting action

I've been asked on Discord how a custom plugin can be ran after posting action (starting new thread, posting a response, etc. ect.).

Misago 0.39 uses a system of classes implementing functions that are called at different stages of posting process. Those classes are named "posting middlewares". You can find those in misago.threads.api.postingendpoint directories, but in this post I'll provide basic information for running custom Python code after one starts new thread or posts new reply.

Assuming you've already created a blank plugin, next step is to create postingmiddleware.py file in it, and implement your basic middleware:

from misago.threads.api.postingendpoint import PostingEndpoint, PostingMiddleware


class PluginMiddleware(PostingMiddleware):
    def use_this_middleware(self):
        # Disable this middleware for edit actions
        return self.mode != PostingEndpoint.EDIT

    def post_save(self, serializer):
        if self.mode == PostingEndpoint.START:
            # run some code when user starts a thread...
            ...

        elif self.mode == PostingEndpoint.REPLY:
            # run some code when user posts a reply....
            ...

Posting middlewares are initialized with following attributes:

self.mode: an int with a mode of posting action (START/REPLY/EDIT)
self.request: the HttpRequest instance
self.category: the Category instance
self.thread: the Thread instance
self.post: the Post instance
self.user: the User instance
self.user_acl: user's permissions

There is no plugin hook in Misago that plugin can hook up custom posting Middleware in. But if you are using misago-docker, you can override the configuration by creating settings_override.py file in right place. See the documentation for more information.

Here's Misago 0.39 MISAGO_POSTING_MIDDLEWARES setting:

MISAGO_POSTING_MIDDLEWARES = [
    # Always keep FloodProtectionMiddleware middleware first one
    "misago.threads.api.postingendpoint.floodprotection.FloodProtectionMiddleware",
    "misago.threads.api.postingendpoint.category.CategoryMiddleware",
    "misago.threads.api.postingendpoint.privatethread.PrivateThreadMiddleware",
    "misago.threads.api.postingendpoint.reply.ReplyMiddleware",
    "misago.threads.api.postingendpoint.moderationqueue.ModerationQueueMiddleware",
    "misago.threads.api.postingendpoint.attachments.AttachmentsMiddleware",
    "misago.threads.api.postingendpoint.participants.ParticipantsMiddleware",
    "misago.threads.api.postingendpoint.pin.PinMiddleware",
    "misago.threads.api.postingendpoint.close.CloseMiddleware",
    "misago.threads.api.postingendpoint.hide.HideMiddleware",
    "misago.threads.api.postingendpoint.protect.ProtectMiddleware",
    "misago.threads.api.postingendpoint.recordedit.RecordEditMiddleware",
    "misago.threads.api.postingendpoint.updatestats.UpdateStatsMiddleware",
    "misago.threads.api.postingendpoint.mentions.MentionsMiddleware",
    "misago.threads.api.postingendpoint.syncprivatethreads.SyncPrivateThreadsMiddleware",
    # Always keep SaveChangesMiddleware middleware after all state-changing middlewares
    "misago.threads.api.postingendpoint.savechanges.SaveChangesMiddleware",
    # Those middlewares are last because they don't change app state
    "misago.threads.api.postingendpoint.notifications.NotificationsMiddleware",
]

You can paste this code in your settings_override.py. You should then update it by adding a new entry with path to your plugin's posting middleware at the end.