Use error message from the server when comment failed

app/assets/javascripts/app/models/post/interactions.js

@@ -95,8 +95,8 @@ app.models.Post.Interactions = Backbone.Model.extend({
     var self = this;
     options = options || {};
 
-    this.comments.make(text).fail(function () {
-      app.flashMessages.error(Diaspora.I18n.t("failed_to_comment"));
+    this.comments.make(text).fail(function(response) {
+      app.flashMessages.handleAjaxError(response);
       if (options.error) { options.error(); }
     }).done(function() {
       self.post.set({participation: true});

app/controllers/comments_controller.rb

@@ -12,11 +12,17 @@ class CommentsController < ApplicationController
   end
 
   def create
-    comment = comment_service.create(params[:post_id], params[:text])
+    begin
+      comment = comment_service.create(params[:post_id], params[:text])
+    rescue ActiveRecord::RecordNotFound
+      render text: I18n.t("javascripts.failed_to_comment"), status: 404
+      return
+    end
+
     if comment
       respond_create_success(comment)
     else
-      render nothing: true, status: 404
+      render text: I18n.t("javascripts.failed_to_comment"), status: 422
     end
   end
 

spec/controllers/comments_controller_spec.rb

@@ -67,6 +67,7 @@ describe CommentsController, :type => :controller do
       expect(alice).not_to receive(:comment)
       post :create, comment_hash
       expect(response.code).to eq("404")
+      expect(response.body).to eq(I18n.t("javascripts.failed_to_comment"))
     end
   end
 

spec/javascripts/app/models/post/interacations_spec.js

@@ -286,6 +286,16 @@ describe("app.models.Post.Interactions", function(){
         jasmine.Ajax.requests.mostRecent().respondWith({status: 400});
         expect(error).toHaveBeenCalled();
       });
+
+      it("displays a flash message", function() {
+        spyOn(app.flashMessages, "handleAjaxError").and.callThrough();
+        this.interactions.comment("text");
+        jasmine.Ajax.requests.mostRecent().respondWith({status: 400, responseText: "error message"});
+
+        expect(app.flashMessages.handleAjaxError).toHaveBeenCalled();
+        expect(app.flashMessages.handleAjaxError.calls.argsFor(0)[0].responseText).toBe("error message");
+        expect(spec.content().find(".flash-message")).toBeErrorFlashMessage("error message");
+      });
     });
   });
 });

spec/javascripts/app/views/comment_stream_view_spec.js

@@ -116,9 +116,6 @@ describe("app.views.CommentStream", function(){
         it("doesn't add the comment to the view", function() {
           this.request.respondWith({status: 500});
           expect(this.view.$(".comment-content p").text()).not.toEqual("a new comment");
-          expect(this.view.$(".flash-message")).toBeErrorFlashMessage(
-            "Failed to comment. Maybe the author is ignoring you?"
-          );
         });
 
         it("doesn't reset the comment box value", function() {