Level 2 (related model) scope over REST - strongloop api

I found in the documentation that scopes enable you to specify commonly-used queries that you can reference as method calls on a model. Below i have a categories model. I am trying to create scopes that applies to the relation with model games. Unfortunately the below does nothing. How can I get scopes to apply to relation as shown below?

GET /Categories/{id}/games - This gets all games

common/models/category.json

"relations": {
    "categories": {
      "type": "hasMany",
      "model": "game",
      "foreignKey": ""
    }
},

/common/models/game.json

 "scopes": {
    "mature": {"where": {"mature": true}}
  },
  "validations": [],
  "relations": {
    "category": {
      "type": "belongsTo",
      "model": "category",
      "foreignKey": ""
    }
  }

I want to be able to get the data through endpoing: /Categories/{id}/games/mature

Table schema:

catgories

category_name       category_id 
-------------       -----------
fighting            1001
racing              1002
sports              1003

games

game_id         game_name           category_id     mature
-----------     ------------        -----------     --------------
13KXZ74XL8M     Tekken              10001           true
138XZ5LPJgM     Forza               10002           false

Solution

Loopback api is based on swagger and scopes is a new concept in loopback.

Currently it doesn't have support for related methods i.e. you cannot access it from a related model i.e category (in your case) but only from model where the scope is defined i.e. game.

Thus you can achieve what you want right now using remote methods.

By Using Remote Methods. Loopback Remote Methods

common/models/category.js add the following lines.

module.exports = function(Category) {

    Category.mature = function(id, filter, callback) {
        var app = this.app;
        var Game = app.models.Game;
        if(filter === undefined){
             filter = {};
        }

        filter.where  = filter.where || {};

        filter.where.categoryId =  id;
        filter.where.mature = true;

        Game.find(filter, function(err, gameArr) {
            if (err) return callback(err);
            console.log(gameArr);
            callback(null, gameArr);
        });
    }

    Category.remoteMethod(
        'mature', {
            accepts: [{
                arg: 'id',
                type: 'number',
                required: true
            },
            {
                arg: 'filter',
                type: 'object',
                required: false
            }
            ],
            // mixing ':id' into the rest url allows $owner to be determined and used for access control
            http: {
                path: '/:id/games/mature',
                verb: 'get'
            },
            returns: {
                arg: 'games',
                type: 'array'
            }
        }
    );

};

Now in your common/models/category.json Add this to your ACL property.

.....
.....
"acls": [
  {
     "principalType": "ROLE",
     "principalId": "$everyone",
     "permission": "ALLOW",
     "property": "mature"
  }
]

Now you can get all your game of mature type by get method http://0.0.0.0:3000/api/categories/:id/games/mature

Or you can also try the API from loopback-explorer now.