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How to Add Hooks

Bulbgraph.png   This feature is available starting from RMP26



Hooks provide an easy mechanism to extend functionality from external module. It basically consists on a lightweight mechanism that allows to inject dependencies from third party modules.

There are two roles for hooks:

Bulbgraph.png   Note from Retail version 2014Q3 the recommended API has changed, instead of OB.MobileApp.model.hookManager use OB.UTIL.HookManager to access the hook manager

How to define the hook in the base module

Base module needs to define which are the points other modules can extend through hooks. This is done with the following code:

  OB.UTIL.HookManager.executeHooks(hookName, args, callback);

When this code is reached, all the hooks defined by external modules for this hookName will be sequentially executed. Finally the callback function will be invoked.

In case there are no external modules providing functionality for this hook, callback function will be directly executed.

The 3 parameters this method accept are:

How to provide logic in external modules

When there is a base module that defines a hook as mentioned in the previous section, external modules can provide logic to be executed at that point in the following manner:

OB.UTIL.HookManager.registerHook('BASMOD_HookName', function (args, callbacks) {
  // execute all your logic here
  // This is a MUST to properly manage callbacks
  OB.UTIL.HookManager.callbackExecutor(args, callbacks);

registerHook function receives 2 parameters:


This example shows how is code for hooks in both sides, base and external module.

// This emulates the code in external modules
OB.UTIL.HookManager.registerHook('test1', function(args, c){
  console.log('  test 1 f1');
  OB.UTIL.HookManager.callbackExecutor(args, c);
OB.UTIL.HookManager.registerHook('test1', function(args, c){
  console.log('  test 1 f2');
  OB.UTIL.HookManager.callbackExecutor(args, c);
OB.UTIL.HookManager.registerHook('test2', function(args, c){
  console.log('  test 2 f1', args);
  OB.UTIL.HookManager.callbackExecutor(args, c);
OB.UTIL.HookManager.registerHook('test2', function(args, c){
  console.log('  test 2 f2', args);
  OB.UTIL.HookManager.callbackExecutor(args, c);
// This is the code that would be in the base module
console.log('start test1 hook');
OB.UTIL.HookManager.executeHooks('test1', null, function(){
  console.log('done test1');
}); // call with callback, no args
console.log('\nstart test2 hook');
OB.UTIL.HookManager.executeHooks('test2', 'args'); // call without callback
console.log('\nstart test3 hook');
OB.UTIL.HookManager.executeHooks('test3', 'args', function(){
  console.log('done test3');
}); // call without hooks
console.log('\nstart test4 hook');
OB.UTIL.HookManager.executeHooks('test4'); //no hooks, no callback
console.log('\ndone all');

The output of this example is:

start test1 hook
  test 1 f1
  test 1 f2
done test1

start test2 hook
  test 2 f1 args
  test 2 f2 args

start test3 hook
done test3

start test4 hook

done all

Hooks in Web POS

This document lists the hooks available in Web POS.

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