refactor: remove the fast server

lib/postal/tracking_middleware.rb

@@ -0,0 +1,105 @@
+module Postal
+  class TrackingMiddleware
+
+    TRACKING_PIXEL = File.read(Rails.root.join('app', 'assets', 'images', 'tracking_pixel.png'))
+
+    def initialize(app = nil)
+      @app = app
+    end
+
+    def call(env)
+      unless env['HTTP_X_POSTAL_TRACK_HOST'].to_i == 1
+        return @app.call(env)
+      end
+
+      request = Rack::Request.new(env)
+
+      case request.path
+      when /\A\/img\/([a-z0-9\-]+)\/([a-z0-9\-]+)/i
+        server_token = $1
+        message_token = $2
+        dispatch_image_request(request, server_token, message_token)
+      when /\A\/([a-z0-9\-]+)\/([a-z0-9\-]+)/i
+        server_token = $1
+        link_token = $2
+        dispatch_redirect_request(request, server_token, link_token)
+      else
+        [200, {}, ["Hello."]]
+      end
+    end
+
+    private
+
+    def dispatch_image_request(request, server_token, message_token)
+      message_db = get_message_db_from_server_token(server_token)
+      if message_db.nil?
+        return [404, {}, ['Invalid Server Token']]
+      end
+
+      begin
+        message = message_db.message(:token => message_token)
+        message.create_load(request)
+      rescue Postal::MessageDB::Message::NotFound
+        # This message has been removed, we'll just continue to serve the image
+      rescue => e
+        # Somethign else went wrong. We don't want to stop the image loading though because
+        # this is our problem. Log this exception though.
+        Raven.capture_exception(e) if defined?(Raven)
+      end
+
+      source_image = request.params['src']
+      case source_image
+      when nil
+        headers = {}
+        headers['Content-Type'] = "image/png"
+        headers['Content-Length'] = TRACKING_PIXEL.bytesize.to_s
+        return [200, headers, [TRACKING_PIXEL]]
+      when /\Ahttps?\:\/\//
+        response = Postal::HTTP.get(source_image, :timeout => 3)
+        if response[:code] == 200
+          headers = {}
+          headers['Content-Type'] = response[:headers]['content-type']&.first
+          headers['Last-Modified'] = response[:headers]['last-modified']&.first
+          headers['Cache-Control'] = response[:headers]['cache-control']&.first
+          headers['Etag'] = response[:headers]['etag']&.first
+          headers['Content-Length'] = response[:body].bytesize.to_s
+          return [200, headers, [response[:body]]]
+        else
+          return [404, {}, ['Not found']]
+        end
+      else
+        return [400, {}, ['Invalid/missing source image']]
+      end
+    end
+
+    def dispatch_redirect_request(request, server_token, link_token)
+      message_db = get_message_db_from_server_token(server_token)
+      if message_db.nil?
+        return [404, {}, ['Invalid Server Token']]
+      end
+
+      link = message_db.select(:links, :where => {:token => link_token}, :limit => 1).first
+      if link.nil?
+        return [404, {}, ['Link not found']]
+      end
+
+      time = Time.now.to_f
+      if link['message_id']
+        message_db.update(:messages, {:clicked => time}, :where => {:id => link['message_id']})
+        message_db.insert(:clicks, {:message_id => link['message_id'], :link_id => link['id'], :ip_address => request.ip, :user_agent => request.user_agent, :timestamp => time})
+        SendWebhookJob.queue(:main, :server_id => message_db.server_id, :event => 'MessageLinkClicked', :payload => {:_message => link['message_id'], :url => link['url'], :token => link['token'], :ip_address => request.ip, :user_agent => request.user_agent})
+      end
+
+      return [307, {'Location' => link['url']}, ["Redirected to: #{link['url']}"]]
+    end
+
+    def get_message_db_from_server_token(token)
+      if server = ::Server.find_by_token(token)
+        server.message_db
+      else
+        nil
+      end
+    end
+
+  end
+end