check last_write_at field when applying rate limits to channels

app/controllers/channels_controller.rb

@@ -312,7 +312,7 @@ class ChannelsController < ApplicationController
       talkback_key = params[:talkback_key] || false;
 
       # rate limit posts if channel is not social and timespan is smaller than the allowed window
-      render :text => '0' and return if (RATE_LIMIT && !tstream && !talkback_key && !channel.social && Time.now < channel.updated_at + RATE_LIMIT_FREQUENCY.to_i.seconds)
+      render :text => '0' and return if (RATE_LIMIT && !tstream && !talkback_key && !channel.social && channel.last_write_at.present? && Time.now < (channel.last_write_at + RATE_LIMIT_FREQUENCY.to_i.seconds))
 
       # if social channel, latitude MUST be present
       render :text => '0' and return if (channel.social && params[:latitude].blank?)
@@ -323,6 +323,8 @@ class ChannelsController < ApplicationController
       feed.entry_id = entry_id
       # set user agent
       channel.user_agent = get_header_value('USER_AGENT')
+      # set the last write at time
+      channel.last_write_at = Time.now
 
       # try to get created_at datetime if appropriate
       if params[:created_at].present?

app/models/channel.rb

@@ -48,6 +48,7 @@
 #  user_agent                :string(255)
 #  realtime_io_serial_number :string(36)
 #  metadata                  :text
+#  last_write_at             :datetime
 #
 
 class Channel < ActiveRecord::Base

db/migrate/20150311201046_add_last_write_at_to_channels.rb

@@ -0,0 +1,6 @@
+class AddLastWriteAtToChannels < ActiveRecord::Migration
+  def change
+    add_column :channels, :last_write_at, :datetime
+  end
+end
+

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20141024161555) do
+ActiveRecord::Schema.define(version: 20150311201046) do
 
   create_table "active_admin_comments", force: true do |t|
     t.string   "namespace"
@@ -105,6 +105,7 @@ ActiveRecord::Schema.define(version: 20141024161555) do
     t.string   "user_agent"
     t.string   "realtime_io_serial_number", limit: 36
     t.text     "metadata"
+    t.datetime "last_write_at"
   end
 
   add_index "channels", ["latitude", "longitude"], name: "index_channels_on_latitude_and_longitude", using: :btree

spec/models/channel_spec.rb

@@ -49,6 +49,7 @@
 #  user_agent                :string(255)
 #  realtime_io_serial_number :string(36)
 #  metadata                  :text
+#  last_write_at             :datetime
 #
 
 require 'spec_helper'