POS Longpolling

It is a custom odoo module made by IT-Projects LLC, which allows sending instant updates to the POS interfaces from backend.

It provides following methods in Backend side:

• self.env['pos.config].send_to_all_poses(channel_name, data): broadcasts messages to all opened POSes (see example)
• pos_set._send_to_channel(channel_name, data): broadcasts message to the POSes in pos_set (see example)
• _send_to_channel_by_id(self, dbname, pos_id, channel_name): sends message to exact POS pos_id, uses data base name dbname , channel_name, message='PONG' (see example)

Note

POS will get notification only if it’s subscribed to the specified channel_name.

For Client side the methods are:

• add_bus(key, sync_server): allows to create additional Bus to sync data with another Sync Server (see example in pos_multi_session - it gets data from local server to speed up synchronization)

Note

You don’t need to use add_bus if you connect with your regular odoo server.

• add_channel_callback: function(channel_name, callback, thisArg): subscribes to specific channel (see example)

Let’s check example of usage taking as a basis Sync Partners in POS module:

Sync Partners in POS module

This module on each partner update (in Backend) notifies POSes to update partner data.

Here you can see how it uses pos_longpolling:

BACKEND

• On partner update send_field_updates method. is called:

@api.model
def send_field_updates(self, partner_ids, action=''):
    channel_name = "pos_partner_sync"
    data = {'message': 'update_partner_fields', 'action': action, 'partner_ids': partner_ids}
    self.env['pos.config'].send_to_all_poses(channel_name, data)

• It uses send_to_all_poses method.

CLIENT

• On POS starting it’s subscribed to channel pos_partner_sync.

initialize: function () {
  PosModelSuper.prototype.initialize.apply(this, arguments);
  var self = this;
  this.ready.then(function () {
    self.bus.add_channel_callback("pos_partner_sync", self.on_barcode_updates, self);
    });
},

• On notification on_barcode_updates is called, which reloads partner data:

on_barcode_updates: function(data){
  var self = this;
  if (data.message === 'update_partner_fields') {
    var def = new $.Deferred();
    if (data.action && data.action === 'unlink') {
    // partner is deleted. Make necessary updates in UI
      this.remove_unlinked_partners(data.partner_ids);
      def.resolve();
    } else {
    // reload partner data
        def = self.load_new_partners(data.partner_ids);
      }
    return def.done(function(){
      var opened_client_list_screen = self.gui.get_current_screen() === 'clientlist' && self.gui.screen_instances.clientlist;
      if (opened_client_list_screen){
        // rerender partner list
        opened_client_list_screen.update_client_list_screen(data.partner_ids);
      }
    });
  }
},