diff --git a/lib/discourse_plugin_registry.rb b/lib/discourse_plugin_registry.rb
index 697d93474f4..53406bf0f96 100644
--- a/lib/discourse_plugin_registry.rb
+++ b/lib/discourse_plugin_registry.rb
@@ -116,6 +116,8 @@ class DiscoursePluginRegistry
define_filtered_register :summarization_strategies
+ define_filtered_register :post_action_notify_user_handlers
+
def self.register_auth_provider(auth_provider)
self.auth_providers << auth_provider
end
diff --git a/lib/guardian/post_guardian.rb b/lib/guardian/post_guardian.rb
index 7c775b5453a..ec11c01db46 100644
--- a/lib/guardian/post_guardian.rb
+++ b/lib/guardian/post_guardian.rb
@@ -58,7 +58,19 @@ module PostGuardian
if action_key == :notify_user &&
!@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map)
- return false
+ # The modifier below is used to add additional permissions for notifying users.
+ # In core the only method of notifying a user is personal messages so we check if the
+ # user can PM. Plugins can extend the behavior of how users are notifier via `notify_user`
+ # post action, and this allows extension for that use case.
+ can_notify = false
+ can_notify =
+ DiscoursePluginRegistry.apply_modifier(
+ :post_guardian_can_notify_user,
+ can_notify,
+ self,
+ post,
+ )
+ return can_notify
end
# we allow flagging for trust level 1 and higher
diff --git a/lib/plugin/instance.rb b/lib/plugin/instance.rb
index a3f3887b3ab..af82b6411a1 100644
--- a/lib/plugin/instance.rb
+++ b/lib/plugin/instance.rb
@@ -1238,6 +1238,14 @@ class Plugin::Instance
DiscoursePluginRegistry.register_summarization_strategy(strategy, self)
end
+ ##
+ # Register a block that will be called when PostActionCreator is going to notify a
+ # user of a post action. If any of these handlers returns false the default PostCreator
+ # call will be skipped.
+ def register_post_action_notify_user_handler(handler)
+ DiscoursePluginRegistry.register_post_action_notify_user_handler(handler, self)
+ end
+
protected
def self.js_path
diff --git a/lib/post_action_creator.rb b/lib/post_action_creator.rb
index 409bb94eb0b..f1e46d855ca 100644
--- a/lib/post_action_creator.rb
+++ b/lib/post_action_creator.rb
@@ -116,12 +116,16 @@ class PostActionCreator
# create meta topic / post if needed
if @message.present? && %i[notify_moderators notify_user spam].include?(@post_action_name)
creator = create_message_creator
- post = creator.create
- if creator.errors.present?
- result.add_errors_from(creator)
- return result
+ # We need to check if the creator exists because it's possible `create_message_creator` returns nil
+ # in the event that a `post_action_notify_user_handler` evaluated to false, haulting the post creation.
+ if creator
+ post = creator.create
+ if creator.errors.present?
+ result.add_errors_from(creator)
+ return result
+ end
+ @meta_post = post
end
- @meta_post = post
end
begin
@@ -339,8 +343,16 @@ class PostActionCreator
else
create_args[:subtype] = TopicSubtype.notify_user
- create_args[:target_usernames] = if @post_action_name == :notify_user
- @post.user.username
+ if @post_action_name == :notify_user
+ create_args[:target_usernames] = @post.user.username
+
+ # Evaluate DiscoursePluginRegistry.post_action_notify_user_handlers.
+ # If any return false, return early from this method
+ handler_values =
+ DiscoursePluginRegistry.post_action_notify_user_handlers.map do |handler|
+ handler.call(@created_by, @post, @message)
+ end
+ return if handler_values.any? { |value| value == false }
elsif @post_action_name != :notify_moderators
# this is a hack to allow a PM with no recipients, we should think through
# a cleaner technique, a PM with myself is valid for flagging
diff --git a/spec/lib/post_action_creator_spec.rb b/spec/lib/post_action_creator_spec.rb
index 81aeba92dfd..fef228d75b3 100644
--- a/spec/lib/post_action_creator_spec.rb
+++ b/spec/lib/post_action_creator_spec.rb
@@ -327,4 +327,73 @@ RSpec.describe PostActionCreator do
)
end
end
+
+ describe "With plugin adding post_action_notify_user_handlers" do
+ let(:message) { "oh that was really bad what you said there" }
+ let(:plugin) { Plugin::Instance.new }
+
+ after { DiscoursePluginRegistry.reset! }
+
+ it "evaluates all handlers and creates post if none return false" do
+ plugin.register_post_action_notify_user_handler(
+ Proc.new do |user, post, message|
+ MessageBus.publish("notify_user", { user_id: user.id, message: message })
+ end,
+ )
+
+ plugin.register_post_action_notify_user_handler(
+ Proc.new do |user, post, message|
+ MessageBus.publish("notify_user", { poster_id: post.user_id, message: message })
+ end,
+ )
+
+ messages =
+ MessageBus.track_publish("notify_user") do
+ result =
+ PostActionCreator.new(
+ user,
+ post,
+ PostActionType.types[:notify_user],
+ message: message,
+ flag_topic: false,
+ ).perform
+ post_action = result.post_action
+ expect(post_action.related_post).to be_present
+ end
+
+ expect(
+ messages.find { |m| m.data[:user_id] == user.id && m.data[:message] == message },
+ ).to be_present
+ expect(
+ messages.find { |m| m.data[:poster_id] == post.user_id && m.data[:message] == message },
+ ).to be_present
+ end
+
+ it "evaluates all handlers and doesn't create a post one returns false" do
+ plugin.register_post_action_notify_user_handler(
+ Proc.new do |user, post, message|
+ MessageBus.publish("notify_user", { user_id: user.id, message: message })
+ false
+ end,
+ )
+
+ messages =
+ MessageBus.track_publish("notify_user") do
+ result =
+ PostActionCreator.new(
+ user,
+ post,
+ PostActionType.types[:notify_user],
+ message: message,
+ flag_topic: false,
+ ).perform
+ post_action = result.post_action
+ expect(post_action.related_post).not_to be_present
+ end
+
+ expect(
+ messages.find { |m| m.data[:user_id] == user.id && m.data[:message] == message },
+ ).to be_present
+ end
+ end
end