FEATURE: compose a new pre-filled private message to a group via URL

app/assets/javascripts/discourse/routes/new-message.js.es6

@@ -1,9 +1,13 @@
+import Group from 'discourse/models/group';
+
 export default Discourse.Route.extend({
   beforeModel: function(transition) {
     const self = this;
     if (Discourse.User.current()) {
       // User is logged in
       self.replaceWith('discovery.latest').then(function(e) {
+        if (transition.queryParams.username) {
+          // send a message to user
           Discourse.User.findByUsername(transition.queryParams.username).then((user) => {
             if (user.can_send_private_message_to_user) {
               Ember.run.next(function() {
@@ -15,6 +19,20 @@ export default Discourse.Route.extend({
           }).catch(() => {
             bootbox.alert(I18n.t("generic_error"));
           });
+        } else {
+          // send a message to group
+          Group.find(transition.queryParams.groupname).then((group) => {
+            if (!group.automatic && group.mentionable) {
+              Ember.run.next(function() {
+                e.send('createNewMessageViaParams', group.name, transition.queryParams.title, transition.queryParams.body);
+              });
+            } else {
+              bootbox.alert(I18n.t("composer.cant_send_pm", {username: group.name}));
+            }
+          }).catch(() => {
+            bootbox.alert(I18n.t("generic_error"));
+          });
+        }
       });
     } else {
       // User is not logged in

app/models/group.rb

@@ -362,6 +362,10 @@ class Group < ActiveRecord::Base
     true
   end
 
+  def mentionable?(user, group_id)
+    Group.mentionable(user).where(id: group_id).exists?
+  end
+
   protected
 
     def name_format_validator

app/serializers/basic_group_serializer.rb

@@ -12,7 +12,8 @@ class BasicGroupSerializer < ApplicationSerializer
              :grant_trust_level,
              :incoming_email,
              :notification_level,
-             :has_messages
+             :has_messages,
+             :mentionable
 
   def include_incoming_email?
     scope.is_staff?
@@ -27,4 +28,8 @@ class BasicGroupSerializer < ApplicationSerializer
     scope.authenticated?
   end
 
+  def mentionable
+    object.mentionable?(scope.user, object.id)
+  end
+
 end

spec/controllers/admin/groups_controller_spec.rb

@@ -33,7 +33,8 @@ describe Admin::GroupsController do
         "grant_trust_level"=>nil,
         "incoming_email"=>nil,
         "notification_level"=>2,
-        "has_messages"=>false
+        "has_messages"=>false,
+        "mentionable"=>false
       }])
     end