Attach the server error response to failed notifications

README.md

@@ -62,6 +62,34 @@ connection.write(notification.message)
 connection.close
 ```
 
+### Logging server errors
+The notification server can respond with some error information for failed deliveries. By default, this information is logged to STDOUT.
+
+Logger initialization can be customized:
+
+```ruby
+APN = Houston::Client.development
+APN.logger = Logger.new(STDERR) # will log to STDERR
+
+APN.logger = Rails.logger # if using houston from a rails app, will use the Rails application logger.
+
+```
+
+Learn more about logger initialization here http://www.ruby-doc.org/stdlib-2.0.0/libdoc/logger/rdoc/Logger.html#class-Logger-label-How+to+create+a+logger
+
+Server error messages on `push` calls are logged at WARN level.
+
+The error code and matching message can be accessed per notification, for instance:
+
+```ruby
+APN.push(notification)
+# imagine notification failure by server error on push
+if notification.apns_error
+  puts "Failed to send notification. Server responded '#{notification.apns_error}'. Error code was #{notification.apns_error_code}."
+end
+```
+
+
 ### Feedback Service
 
 Apple provides a feedback service to query for unregistered device tokens, these are devices that have failed to receive a push notification and should be removed from your application. You should periodically query for and remove these devices, Apple audits providers to ensure they are removing unregistered devices. To obtain the list of unregistered device tokens:

lib/houston/client.rb

@@ -1,12 +1,14 @@
 module Houston
+  require 'logger'
+
   APPLE_PRODUCTION_GATEWAY_URI = "apn://gateway.push.apple.com:2195"
   APPLE_PRODUCTION_FEEDBACK_URI = "apn://feedback.push.apple.com:2196"
 
   APPLE_DEVELOPMENT_GATEWAY_URI = "apn://gateway.sandbox.push.apple.com:2195"
   APPLE_DEVELOPMENT_FEEDBACK_URI = "apn://feedback.sandbox.push.apple.com:2196"
 
   class Client
-    attr_accessor :gateway_uri, :feedback_uri, :certificate, :passphrase, :timeout
+    attr_accessor :gateway_uri, :feedback_uri, :certificate, :passphrase, :timeout, :logger
 
     class << self
       def development
@@ -72,6 +74,8 @@ def push(*notifications)
 
       if error
         command, status, index = error.unpack("ccN")
+        notifications[index].apns_error_code = status
+        logger.warn "Push failed for '#{notifications[index].inspect}'. Error was '#{notifications[index].apns_error}'."
         notifications.slice!(0..index)
         notifications.each(&:mark_as_unsent!)
         push(*notifications)
@@ -96,5 +100,10 @@ def unregistered_devices
     def devices
       unregistered_devices.collect{|device| device[:token]}
     end
+
+    def logger
+      @logger ||= Logger.new(STDOUT)
+    end
+
   end
 end

lib/houston/notification.rb

@@ -4,7 +4,8 @@ module Houston
   class Notification
     MAXIMUM_PAYLOAD_SIZE = 256
 
-    attr_accessor :token, :alert, :badge, :sound, :content_available, :custom_data, :id, :expiry, :priority
+    attr_accessor :token, :alert, :badge, :sound, :content_available, :custom_data, :id, :expiry, :priority,
+      :apns_error_code
     attr_reader :sent_at
 
     alias :device :token
@@ -59,6 +60,22 @@ def valid?
       payload.to_json.bytesize <= MAXIMUM_PAYLOAD_SIZE
     end
 
+    def apns_error
+      {
+        0 => nil,
+        1 => "Processing error",
+        2 => "Missing device token",
+        3 => "Missing topic",
+        4 => "Missing payload",
+        5 => "Invalid token size",
+        6 => "Invalid topic size",
+        7 => "Invalid payload size",
+        8 => "Invalid token",
+        10 => "Shutdown",
+        255 => "Unknown error"
+      }[@apns_error_code]
+    end
+
     private
 
     def device_token_item