#2426 refactor to use predetermined referer

app/logical/image_proxy.rb

@@ -0,0 +1,34 @@
+class ImageProxy
+  def self.needs_proxy?(url)
+    fake_referer_for(url).present?
+  end
+
+  def self.fake_referer_for(url)
+    Sources::Site.new(url).strategy.fake_referer
+  end
+
+  def self.get_image(url)
+    if url.blank?
+      raise "Must specify url"
+    end
+
+    if !needs_proxy?(url)
+      raise "Proxy not allowed for this site"
+    end
+
+    uri = URI.parse(url)
+    headers = {
+      "Referer" => fake_referer_for(url),
+      "User-Agent" => "#{Danbooru.config.safe_app_name}/#{Danbooru.config.version}"
+    }
+
+    Net::HTTP.start(uri.host, uri.port) do |http|
+      resp = http.request_get(uri.request_uri, headers)
+      if resp.is_a?(Net::HTTPSuccess)
+        return resp
+      else
+        raise "HTTP error code: #{resp.code} #{resp.message}"
+      end
+    end
+  end
+end