quietly accept dupe comments

Fix #967

.rubocop.yml

@@ -154,7 +154,7 @@ RSpec/BeforeAfterAll:
   Enabled: false
 RSpec/DescribeClass:
   Enabled: false
-Rspec/LetSetup:
+RSpec/LetSetup:
   Enabled: false
 Capybara/FeatureMethods:
   Enabled: false

app/controllers/comments_controller.rb

@@ -34,7 +34,16 @@ class CommentsController < ApplicationController
       end
     end
 
-    # prevent double-clicks of the post button
+    # sometimes on slow connections people resubmit; silently accept it
+    if (already = Comment.find_by(user: comment.user,
+                                  story: comment.story,
+                                  parent_comment_id: comment.parent_comment_id,
+                                  comment: comment.comment))
+      self.render_created_comment(already)
+      return
+    end
+
+    # rate-limit users to one reply per 5m per parent comment
     if params[:preview].blank? &&
        (pc = Comment.where(:story_id => story.id,
                            :user_id => @user.id,
@@ -50,13 +59,7 @@ class CommentsController < ApplicationController
 
     if comment.valid? && params[:preview].blank? && ActiveRecord::Base.transaction { comment.save }
       comment.current_vote = { :vote => 1 }
-
-      if request.xhr?
-        render :partial => "comments/postedreply", :layout => false,
-          :content_type => "text/html", :locals => { :comment => comment }
-      else
-        redirect_to comment.path
-      end
+      self.render_created_comment(comment)
     else
       comment.score = 1
       comment.current_vote = { :vote => 1 }
@@ -65,6 +68,15 @@ class CommentsController < ApplicationController
     end
   end
 
+  def render_created_comment(comment)
+    if request.xhr?
+      render :partial => "comments/postedreply", :layout => false,
+        :content_type => "text/html", :locals => { :comment => comment }
+    else
+      redirect_to comment.path
+    end
+  end
+
   def show
     if !((comment = find_comment) && comment.is_editable_by_user?(@user))
       return render :plain => "can't find comment", :status => 400

app/models/story.rb

@@ -880,7 +880,9 @@ class Story < ApplicationRecord
     if (match = u.match(/\A([^\?]+)\?(.+)\z/))
       params = match[2].split(/[&\?]/)
       # utm_ is google and many others; sk is medium
-      params.reject! {|p| p.match(/^utm_(source|medium|campaign|term|content|referrer)=|^sk=|^gclid=|^fbclid=/) }
+      params.reject! {|p|
+        p.match(/^utm_(source|medium|campaign|term|content|referrer)=|^sk=|^gclid=|^fbclid=/x)
+      }
       u = match[1] << (params.any?? "?" << params.join("&") : "")
     end