CODEWITHSUNDEEP
loopbackjs
Aleks
Aleks

Reputation: 5854

Loopback Model with no datasource

I want to create a model in loopback with very complex logic, impossible to map to any datasource. SO I would like to somehow only generate the CRUD methods skeletons in JS and be able to simply override them, as explained here:

extend the CRUD method in LoopBack

From the outside it should be accessible as any REST API, with all the CRUDs and other methods, typical in loopback.

I would also apply ACLs, authorization and all the stuff to it, just as normal.

How should I proceed? Is this case somewhere formally documented? Are the CRUD methods officially documented, so I can safely override them?

Upvotes: 2

Views: 1121

Answers (2)

adelriosantiago
adelriosantiago

Reputation: 8124

You can create it with the lb model command. Be sure to select:

  • Datasource: (no datasource)
  • Model: Model
  • Expose: Yes
  • Common/server: Common

This will create the files inside common/models. You can do this manually too. A datasource-less model is essentially composed of these file contents:

test.json

{
  "name": "test",
  "base": "Model",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {},
  "validations": [],
  "relations": {},
  "acls": [],
  "methods": {}
}

test.js

'use strict';

module.exports = function(Test) {
    Test.greet = function(msg, cb) {
      cb(null, 'Greetings... ' + msg);
    }

    Test.remoteMethod('greet', {
          accepts: { arg: 'msg', type: 'string' },
          returns: { arg: 'greeting', type: 'string' }
    });
};

This will create a route called /test, with a function named "greet".

Upvotes: 1

Overdrivr
Overdrivr

Reputation: 6576

The loopback node API is documented there.

Just override the methods like in the link you provided. You will need to match the node API of the original method in your overriden method, but apart from that no restrictions. ACLs are decoupled from that so nothing to worry on this side.

However, I don't know how you plan to write a stateless loopback application without using a datasource, since this is where the state is stored. If your loopback application is not stateless, remember that it will not scale (cannot start multiple instances in a cluster), and will do nasty things when it will crash. Can't you just split your problem / simplify it ?

Upvotes: 0

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