add xhr variant detection

app/assets/javascripts/posts.js.erb

@@ -154,7 +154,7 @@
 
   Danbooru.Post.initialize_similar = function() {
     $("#similar-button").click(function(e) {
-      $.get("/iqdb_queries", {"variant": "xhr", "url": $("#post_source").val()}).done(function(html) {$("#iqdb-similar").html(html).show()});
+      $.get("/iqdb_queries", {"url": $("#post_source").val()}).done(function(html) {$("#iqdb-similar").html(html).show()});
       e.preventDefault();
     });
   }

app/assets/javascripts/uploads.js

@@ -61,7 +61,7 @@
 
   Danbooru.Upload.initialize_iqdb_source = function() {
     if (/^https?:\/\//.test($("#normalized_url").val())) {
-      $.get("/iqdb_queries", {"variant": "xhr", "url": $("#normalized_url").val()}).done(function(html) {$("#iqdb-similar").html(html)});
+      $.get("/iqdb_queries", {"url": $("#normalized_url").val()}).done(function(html) {$("#iqdb-similar").html(html)});
     }
   }
 
@@ -77,7 +77,7 @@
 
   Danbooru.Upload.initialize_similar = function() {
     $("#similar-button").click(function(e) {
-      $.get("/iqdb_queries", {"variant": "xhr", "url": $("#upload_source").val()}).done(function(html) {$("#iqdb-similar").html(html).show()});
+      $.get("/iqdb_queries", {"url": $("#upload_source").val()}).done(function(html) {$("#iqdb-similar").html(html).show()});
       e.preventDefault();
     });
   }

app/controllers/iqdb_queries_controller.rb

@@ -1,5 +1,6 @@
 class IqdbQueriesController < ApplicationController
   respond_to :html, :json
+  before_action :detect_xhr
 
   def show
     if params[:url]
@@ -15,10 +16,8 @@ class IqdbQueriesController < ApplicationController
     end
 
     respond_with(@matches) do |fmt|
-      fmt.html
-
-      fmt.html.xhr do
-        render layout: false
+      fmt.html do |html|
+        html.xhr { render layout: false}
       end
       
       fmt.json do
@@ -26,4 +25,12 @@ class IqdbQueriesController < ApplicationController
       end
     end
   end
+
+private
+  
+  def detect_xhr
+    if request.xhr?
+      request.variant = :xhr
+    end
+  end
 end