Ember-data-hal-9000

An ember-data adapter for HAL-style APIs.

See the IETF HAL Spec or this HAL document for more info on HAL.

Compatibility

ember-data-hal-9000 supports ember data pre beta 19, beta 19, and ember data 1.13 support is coming soon.

Ember Data < 1.0.0-beta.19	Ember Data 1.0.0-beta.19.2	Ember Data 1.13
use version 0.1.x	use version 0.2.x	coming soon (version 0.3.x)

Usage

Install ember-data-hal-9000:

• npm install --save-dev ember-data-hal-9000
• Extend your application adapter from the HAL-9000 adapter, e.g.:

// app/adapters/application.js

import HalAdapter from "ember-data-hal-9000/adapter";
export default HalAdapter.extend();

• Extend your application serializer from the HAL-9000 serializer, e.g.:

// app/serializers/application.js

import HalSerializer from "ember-data-hal-9000/serializer";
export default HalSerializer.extend();

Tested with Ember Data versions 1.0.0-beta.15 through 1.0.0-beta.18. Tested with Ember release, beta and canary channels.

Sideloading

HAL specifies that the API should return _embedded values for associations. The HAL serializer will restructure incoming JSON payloads to turn these back into the format that ember-data expects for sideloads. It will restructure arbitrarily deeply nested embeds, and it will delete _links keys when they match embedded properties. Example:

# GET /users/1
{
  id: 1,
  name: 'the user',
  _links: {
    self: { href: '/users/1' },
    pet:  { href: '/users/1/pet' }
  },
  _embedded: {
    pet: {
      id: 'pet-2',
      name: 'fido'
    }
  }
}

# The HAL serializer will restructure this JSON like so:
{
  user: {
    id: 1,
    name: 'the user',
    pet: 'pet-2'      // <-- adds the 'pet' property to user, using the pet id value
  },
  pets: [{
    id: 'pet-2',
    name: 'fido'
  }],
  links: {
    self: '/users/1'
    //  <-- note 'pet' link is deleted since the user's pet was embedded
  }
}

# This code in your route will work.
store.get('user', 1).then(function(user){
  return user.get('pet'); // ember-data will use the sideloaded pet and will not GET /users/1/pet
});

Meta data

The HAL spec mentions that information about a collection resource can be included in the root of the JSON payload, alongside the required _embedded key.

The HAL adapter will read all non-reserved property names (i.e., those other than _embedded and _links) and set them as meta data. For example:

# Assuming GET /users returns this:
{
  _embedded: {
    users: [{...}, ...]
  },
  current_page: 1
}

# Using this code in your route will work:
store.find('user').then(function(){
  console.log( store.metadataFor('user').current_page ); // 1
});

Note that this only works for collection resources. Singular resources, according to the HAL spec, have all their properties in the root of the payload so it is not possible to know which are intended to be meta data.

For this reason, if your API response includes a meta key (for singular or collection requests), the values in the meta will be set. Example:

# Assuming GET /users/1 returns this:
{
  id: 1,
  name: 'the user',
  meta: {
    my_meta_val: true
  }
}

# Using this code in your route will work:
store.find('user', 1).then(function(){
  console.log( store.metadataFor('user').my_meta_val ); // true
});

In addition, for collection resources only, the links will be set on the meta data as well. Example:

# Assuming GET /users returns this:
{
  _embedded: { users: [{...}, ...] },
  _links: {
    self: '/users',
    next: '/users?page=2'
  }
}

# Using this code in your route will work:
store.find('user').then(function(){
  console.log( store.metadataFor('user').links.next ); // '/users?page=2'
});

Links for a singular resource will be available on the 'data' property, i.e.:

store.get('user', 1).then(function(user){
  console.log( user.get('data.links') ); // {self: '/users/1', ... }
});

Note that when a singular resource response includes an embedded resource, the HAL adapter will sideload that embedded resource and delete the link for that resource, if there is one (otherwise ember-data will eagerly follow the link when you get the associated resource). See the example above in the section on sideloading.

Running Tests

• npm test # test all scenarios in config/ember-try.js
• ember try <scenario-name> test --server # test a specific scenario