additional fixes to support iqdbs

app/logical/iqdb/download.rb

@@ -6,11 +6,24 @@ module Iqdb
       @source = source
     end
 
+    def get_referer(url)
+      headers = {}
+      datums = {}
+
+      Downloads::RewriteStrategies::Base.strategies.each do |strategy|
+        url, headers, datums = strategy.new(url).rewrite(url, headers, datums)
+      end
+
+      [url, headers["Referer"]]
+    end
+
     def find_similar
       if Danbooru.config.iqdbs_server
+        url, ref = get_referer(source)
         params = {
           "key" => Danbooru.config.iqdbs_auth_key,
-          "url" => source
+          "url" => url,
+          "ref" => ref
         }
         uri = URI.parse("#{Danbooru.config.iqdbs_server}/similar")
         uri.query = URI.encode_www_form(params)
@@ -18,7 +31,12 @@ module Iqdb
         Net::HTTP.start(uri.host, uri.port) do |http|
           resp = http.request_get(uri.request_uri)
           if resp.is_a?(Net::HTTPSuccess)
-            JSON.parse(resp.body)
+            json = JSON.parse(resp.body)
+            if json.is_a?(Array)
+              json
+            else
+              []
+            end
           else
             raise "HTTP error code: #{resp.code} #{resp.message}"
           end