pundit: convert comments to pundit.

app/controllers/comments_controller.rb

@@ -1,7 +1,6 @@
 class CommentsController < ApplicationController
   respond_to :html, :xml, :json, :atom
   respond_to :js, only: [:new, :destroy, :undelete]
-  before_action :member_only, :except => [:index, :search, :show]
   skip_before_action :api_check
 
   def index
@@ -20,20 +19,25 @@ class CommentsController < ApplicationController
   end
 
   def new
-    @comment = Comment.new(comment_params(:create))
-    @comment.body = Comment.find(params[:id]).quoted_response if params[:id]
+    if params[:id]
+      quoted_comment = Comment.find(params[:id])
+      @comment = authorize Comment.new(post_id: quoted_comment.post_id, body: quoted_comment.quoted_response)
+    else
+      @comment = authorize Comment.new(permitted_attributes(Comment))
+    end
+
     respond_with(@comment)
   end
 
   def update
-    @comment = Comment.find(params[:id])
-    check_privilege(@comment)
-    @comment.update(comment_params(:update))
+    @comment = authorize Comment.find(params[:id])
+    @comment.update(permitted_attributes(@comment))
     respond_with(@comment, :location => post_path(@comment.post_id))
   end
 
   def create
-    @comment = Comment.create(comment_params(:create).merge(creator: CurrentUser.user, creator_ip_addr: CurrentUser.ip_addr))
+    @comment = authorize Comment.new(creator: CurrentUser.user, creator_ip_addr: CurrentUser.ip_addr)
+    @comment.update(permitted_attributes(@comment))
     flash[:notice] = @comment.valid? ? "Comment posted" : @comment.errors.full_messages.join("; ")
     respond_with(@comment) do |format|
       format.html do
@@ -43,13 +47,12 @@ class CommentsController < ApplicationController
   end
 
   def edit
-    @comment = Comment.find(params[:id])
-    check_privilege(@comment)
+    @comment = authorize Comment.find(params[:id])
     respond_with(@comment)
   end
 
   def show
-    @comment = Comment.find(params[:id])
+    @comment = authorize Comment.find(params[:id])
 
     respond_with(@comment) do |format|
       format.html do
@@ -59,15 +62,13 @@ class CommentsController < ApplicationController
   end
 
   def destroy
-    @comment = Comment.find(params[:id])
-    check_privilege(@comment)
+    @comment = authorize Comment.find(params[:id])
     @comment.update(is_deleted: true)
     respond_with(@comment)
   end
 
   def undelete
-    @comment = Comment.find(params[:id])
-    check_privilege(@comment)
+    @comment = authorize Comment.find(params[:id])
     @comment.update(is_deleted: false)
     respond_with(@comment)
   end
@@ -103,19 +104,4 @@ class CommentsController < ApplicationController
 
     respond_with(@comments)
   end
-
-  def check_privilege(comment)
-    if !comment.editable_by?(CurrentUser.user)
-      raise User::PrivilegeError
-    end
-  end
-
-  def comment_params(context)
-    permitted_params = %i[body post_id]
-    permitted_params += %i[do_not_bump_post] if context == :create
-    permitted_params += %i[is_deleted] if context == :update
-    permitted_params += %i[is_sticky] if CurrentUser.is_moderator?
-
-    params.fetch(:comment, {}).permit(permitted_params)
-  end
 end

app/models/comment.rb

@@ -117,10 +117,6 @@ class Comment < ApplicationRecord
     end
   end
 
-  def editable_by?(user)
-    updater_id == user.id || user.is_moderator?
-  end
-
   def reportable_by?(user)
     creator_id != user.id && !creator.is_moderator?
   end

app/policies/comment_policy.rb

@@ -0,0 +1,19 @@
+class CommentPolicy < ApplicationPolicy
+  def update?
+    unbanned? && (user.is_moderator? || record.updater_id == user.id)
+  end
+
+  def can_sticky_comment?
+    user.is_moderator?
+  end
+
+  def permitted_attributes_for_create
+    [:body, :post_id, :do_not_bump_post, (:is_sticky if can_sticky_comment?)].compact
+  end
+
+  def permitted_attributes_for_update
+    [:body, :is_deleted, (:is_sticky if can_sticky_comment?)].compact
+  end
+
+  alias_method :undelete?, :update?
+end

app/views/comments/_form.html.erb

@@ -1,14 +1,16 @@
 <%= error_messages_for :comment %>
 
 <%= edit_form_for(comment, html: { style: ("display: none;" if local_assigns[:hidden]), class: "edit_comment" }) do |f| %>
-  <%= f.hidden_field :post_id %>
+  <% if comment.new_record? %>
+    <%= f.hidden_field :post_id %>
+  <% end %>
   <%= dtext_field "comment", "body", :classes => "autocomplete-mentions", :value => comment.body, :input_id => "comment_body_for_#{comment.id}", :preview_id => "dtext-preview-for-#{comment.id}" %>
   <%= f.button :submit, "Submit" %>
   <%= dtext_preview_button "comment", "body", :input_id => "comment_body_for_#{comment.id}", :preview_id => "dtext-preview-for-#{comment.id}" %>
   <% if comment.new_record? %>
     <%= f.input :do_not_bump_post, :label => "No bump" %>
   <% end %>
-  <% if CurrentUser.is_moderator? %>
+  <% if policy(comment).can_sticky_comment? %>
     <%= f.input :is_sticky, :label => "Post as moderator", :for => "comment_is_sticky" %>
   <% end %>
 <% end %>

app/views/comments/partials/index/_list.html.erb

@@ -28,7 +28,7 @@
     <% end %>
   </div>
 
-  <% if CurrentUser.is_member? %>
+  <% if policy(Comment).create? %>
     <div class="new-comment">
       <p><%= link_to "Post comment", new_comment_path(comment: { post_id: post.id }), :class => "expand-comment-response" %></p>
       <%= render "comments/form", comment: post.comments.new, hidden: true %>

app/views/comments/partials/show/_comment.html.erb

@@ -31,7 +31,7 @@
       </div>
       <%= render "application/update_notice", record: comment %>
       
-      <% if CurrentUser.is_member? %>
+      <% if policy(comment).create? %>
         <menu>
           <% if context == :index_by_comment %>
             <li><%= link_to "Reply", new_comment_path(id: comment, comment: { post_id: comment.post_id }), class: "reply-link" %></li>
@@ -39,7 +39,7 @@
             <li><%= link_to "Reply", new_comment_path(id: comment, comment: { post_id: comment.post_id }), class: "reply-link", remote: true %></li>
           <% end %>
 
-          <% if comment.editable_by?(CurrentUser.user) %>
+          <% if policy(comment).update? %>
             <% if comment.is_deleted? %>
               <li><%= link_to "Undelete", undelete_comment_path(comment.id), method: :post, remote: true %></li>
             <% else %>
@@ -60,7 +60,7 @@
             <li><%= link_to "Report", new_moderation_report_path(moderation_report: { model_type: "Comment", model_id: comment.id }), remote: true %></li>
           <% end %>
         </menu>
-        <% if comment.editable_by?(CurrentUser.user) %>
+        <% if policy(comment).update? %>
           <%= render "comments/form", comment: comment, hidden: true %>
         <% end %>
       <% end %>

test/functional/comments_controller_test.rb

@@ -151,6 +151,7 @@ class CommentsControllerTest < ActionDispatch::IntegrationTest
 
         should "fail if updater is not a moderator" do
           put_auth comment_path(@comment.id), @user, params: {comment: {is_sticky: true}}
+          assert_response 403
           assert_equal(false, @comment.reload.is_sticky)
         end
       end
@@ -169,20 +170,29 @@ class CommentsControllerTest < ActionDispatch::IntegrationTest
       end
 
       should "not allow changing do_not_bump_post or post_id" do
-        as_user do
-          @another_post = create(:post)
-        end
-        put_auth comment_path(@comment.id), @comment.creator, params: {do_not_bump_post: true, post_id: @another_post.id}
+        @another_post = as(@user) { create(:post) }
+
+        put_auth comment_path(@comment.id), @comment.creator, params: { do_not_bump_post: true }
+        assert_response 403
         assert_equal(false, @comment.reload.do_not_bump_post)
-        assert_equal(@post.id, @comment.post_id)
+
+        put_auth comment_path(@comment.id), @comment.creator, params: { post_id: @another_post.id }
+        assert_response 403
+        assert_equal(@post.id, @comment.reload.post_id)
       end
     end
 
     context "new action" do
-      should "redirect" do
+      should "work" do
         get_auth new_comment_path, @user
         assert_response :success
       end
+
+      should "work when quoting a post" do
+        @comment = create(:comment)
+        get_auth new_comment_path(id: @comment.id), @user, as: :javascript
+        assert_response :success
+      end
     end
 
     context "create action" do