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This document explains how to use a device's registration service for Push Notifications and provides a brief overview about it.

Every time an end-user executes a GeneXus application that has the Enable Notifications property enabled, the service configured in the Registration Handler property is automatically executed in order to register and store the device information to be used in the future to send messages to the device.

A Procedure object called NotificationsRegistrationHandler is included as a sample of this service. You can find it in the KB Explorer under Root Module >  GeneXus > SD > Notifications with a typical implementation.

   parm(in:&DeviceType, in:&DeviceId, in:&DeviceToken, in:&DeviceName);

   for each
      where DeviceType = &DeviceType
      where DeviceId  = &DeviceId   
      DeviceToken = &DeviceToken    
      DeviceName = &DeviceName      
   when none
         DeviceType  = &DeviceType
         DeviceId = &DeviceId
         DeviceToken = &DeviceToken
         DeviceName = &DeviceName

The Parm rule must have these four parameters in order to retrieve the device information.

  • &DeviceType : SmartDeviceType
  • &DeviceId : Character(128)
  • &DeviceToken : Character(1000)
  • &DeviceName :Character(128).

After the execution of the service, information like the following is registered:

  • DeviceType :
        Apple or Android
  • DeviceId :
  • DeviceToken :
    When the Notifications Provider property has a value different from "None", this token contains information about the device in a JSON format.
    An example of these data (using OneSignal as Notification Provider) look as follows:

       "DeviceToken": "PJy0nafLvZiXvbGlmYuidCpA7JY5ryuW30KoQmpOs=",
       "DeviceId": "8bb3ud27c7cce885b1c41a3cf5f5bd3m4b22w96d",
       "DeviceType": 1,
       "NotificationPlatform": "OneSignal",
       "NotificationPlatformId": fb508412-2f91-46b1-90e1-f052247d1f8c

*If the DBMS is MySql, DeviceToken must be defined as VarChar(1000), not Char(1000), otherwise it won't record the entire Token

If no Notification Provider is used, the token should look as follows:

  • DeviceName :
       iPhone Mary

With this information, you can start sending messages to registered devices (those that use your application).


  • If you have a completely offline application, and you need this Registration Handler procedure to be generated offline exclusively, set Main property = False and Connectivity Support property = Offline
  • Device registration does not work if you are prototyping with KBN (Knowledge Base Navigator) or simulators.
  • The Registration Handler service is called when the application is opened.


1. Android devices are not being registered

  • Android Sender Id and/or Android Sender API Key properties from the main object are not set.
  • Simulators without Google Play Services don't support Firebase, so they are not being registered. Use devices instead.

See Also

HowTo: Configure Push Notifications in Apple Applications
HowTo: Configure Push Notifications in Android Applications


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