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node.jsderbyjsracerjs

Server-side model change event in DerbyJS 0.6


In DerbyJS:

How do I add event listeners to "The Model", only server side, without having to rely on requests (express middleware)?

Related question I've found: How to create server-side application logic on Racer / DerbyJS?

Of course I can write an express middleware. But the "shared" data model would come in really handy if I could access it without having to rely on a request, and I don't know how to do that without having to put the specific code into the shared codebase.

Use case: order processing for e-commerce software

My model could be like this:

{
  orders: [ {
    id: '1',
    products: [ ... ],
    user: [ ... ],
    token: 'stripe credit card token I get from Client here'
  }, {
    ...
  } ]
}

This way the client could place new orders doing

model.at('orders').add(myOrder);

And the server could process it by listening for 'insert' events:

model.on('insert', 'orders', function(captures, index, newOrders) {
  newOrders.forEach(processOrder);
})

Solution

  • Yes you can!! :)

    You have 2 options.

    Option 1)

    Use app.serverUse to include a server side script, or use the store.js if you have used yo derby-generator. There you can :

    var model = dbStore.createModel();
    model.subscribe("orders", function(){
      model.on("insert", "orders.**", function() {
       ...
      });
    });
    

    Option 2)

    Using https://github.com/derbyparty/derby-hook

    dbStore.hook('create', 'orders', function(id, doc, session, backend) {
      var model = dbStore.createModel();
      var $order = model.at('orders.'+ id);
       ...
    });