#10883 adding const error string DismissPostError to be returned by MessageWillBePosted (#10921)

Adds an exported const string that can be used by plugins to signal a client that the incoming post should be dismissed, instead of the current behavior which just leaves it pending.

app/post.go

@@ -236,7 +236,11 @@ func (a *App) CreatePost(post *model.Post, channel *model.Channel, triggerWebhoo
 		pluginsEnvironment.RunMultiPluginHook(func(hooks plugin.Hooks) bool {
 			replacementPost, rejectionReason := hooks.MessageWillBePosted(pluginContext, post)
 			if rejectionReason != "" {
-				rejectionError = model.NewAppError("createPost", "Post rejected by plugin. "+rejectionReason, nil, "", http.StatusBadRequest)
+				id := "Post rejected by plugin. " + rejectionReason
+				if rejectionReason == plugin.DismissPostError {
+					id = plugin.DismissPostError
+				}
+				rejectionError = model.NewAppError("createPost", id, nil, "", http.StatusBadRequest)
 				return false
 			}
 			if replacementPost != nil {
@@ -245,6 +249,7 @@ func (a *App) CreatePost(post *model.Post, channel *model.Channel, triggerWebhoo
 
 			return true
 		}, plugin.MessageWillBePostedId)
+
 		if rejectionError != nil {
 			return nil, rejectionError
 		}

plugin/hooks.go

@@ -36,6 +36,11 @@ const (
 	TotalHooksId            = iota
 )
 
+const (
+	// DismissPostError dismisses a pending post when the error is returned from MessageWillBePosted.
+	DismissPostError = "plugin.message_will_be_posted.dismiss_post"
+)
+
 // Hooks describes the methods a plugin may implement to automatically receive the corresponding
 // event.
 //
@@ -90,6 +95,7 @@ type Hooks interface {
 	// To reject a post, return an non-empty string describing why the post was rejected.
 	// To modify the post, return the replacement, non-nil *model.Post and an empty string.
 	// To allow the post without modification, return a nil *model.Post and an empty string.
+	// To dismiss the post, return a nil *model.Post and the const DismissPostError string.
 	//
 	// If you don't need to modify or reject posts, use MessageHasBeenPosted instead.
 	//

store/sqlstore/post_store.go

@@ -296,6 +296,7 @@ func (s *SqlPostStore) Get(id string) (*model.PostList, *model.AppError) {
 
 	for _, p := range posts {
 		pl.AddPost(p)
+		pl.AddOrder(p.Id)
 	}
 
 	return pl, nil