(feature) New MessagesWillBeConsumed Server Plugin Hook (#23305)

* feature: implemented basic MessageWillBeConsumed hook and applied on GetSinglePost method.

* use hook in get methods

* chore: refactored hook usage and created utils functions to apply hook

* bugfix: single post not updating

* chore: adjusted hook to return post

* chore: reverted some uneeded  changes

* chore: updated hook to accept slice of posts

* bugfix: slice filled with niil values

* chore: MessageWillBeConsumed ranamed to MessagesWillBeConsumed

* Update plugin/hooks.go

Co-authored-by: Jesse Hallam <jesse@thehallams.ca>

* Add feature flag

* Update min version

* update tests to account for feature flag

* fix linting issues

---------

Co-authored-by: Matej Topolovac <>
Co-authored-by: mtopolovac <43346061+mtopolovac@users.noreply.github.com>
Co-authored-by: Jesse Hallam <jesse@thehallams.ca>
Co-authored-by: Kevin Hsieh <kevinh@qrypt.com>
Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>

server/public/plugin/hooks.go

@@ -53,6 +53,7 @@ const (
 	NotificationWillBePushedID                = 35
 	UserHasBeenDeactivatedID                  = 36
 	MessageHasBeenDeletedID                   = 37
+	MessagesWillBeConsumedID                  = 38
 	TotalHooksID                              = iota
 )
 
@@ -170,6 +171,15 @@ type Hooks interface {
 	// Minimum server version: 5.2
 	MessageHasBeenUpdated(c *Context, newPost, oldPost *model.Post)
 
+	// MessagesWillBeConsumed is invoked when a message is requested by a client before it is returned
+	// to the client
+	//
+	// Note that this method will be called for posts created by plugins, including the plugin that
+	// created the post.
+	//
+	// Minimum server version: 9.3
+	MessagesWillBeConsumed(posts []*model.Post) []*model.Post
+
 	// MessageHasBeenDeleted is invoked after the message has been deleted from the database.
 	// Note that this method will be called for posts deleted by plugins, including the plugin that
 	// deleted the post.