Page Contents

Overview

The LoopBack oAuth 2.0 component enables LoopBack applications to function as oAuth 2.0 providers to authenticate and authorize client applications and users to access protected API endpoints.

The oAuth 2.0 protocol implementation is based on OAuth2orize and Passport.

For more information on oAuth 2.0, see:

Internet Engineering Taskforce (IETF) technical specifications (Request for Comments or RFC):

Key elements

The LoopBack OAuth 2.0 component has the following key elements:

  • Authorization server: Issues access tokens to the client after successfully authenticating the resource owner and obtaining authorization. The component implements the OAuth 2.0 protocol endpoints, including authorization endpoint  and token endpoint.

  • Resource server: Hosts the protected resources, and is capable of accepting and responding to protected resource requests using access tokens. The component provides middleware to protect API endpoints so that only requests with valid OAuth 2.0 access tokens are accepted. It also establishes identities such as client application ID and user ID for further access control and personalization.

The authorization server may be the same server as the resource server or separate. A single authorization server may issue access tokens accepted by multiple resource servers.

The component defines the following models to manage OAuth 2.0 metadata such as access tokens, authorization codes, clients (applications), and resource owners (users):

  • OAuthAccessToken (persisting access tokens)
  • OAuthAuthorizationCode (persisting authorization codes)

It also uses the user and application model from the loopback module:

  • User (managing resource owners)
  • Application (managing client applications)

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Installation

Install the component as usual:

$ npm install loopback-component-oauth2

Using the OAuth2 component

Use in an application as follows:

var oauth2 = require('loopback-component-oauth2');

var options = {
  dataSource: app.dataSources.db, // Data source for oAuth2 metadata persistence
  loginPage: '/login', // The login page URL
  loginPath: '/login' // The login form processing URL
};

oauth2.oAuth2Provider(
  app, // The app instance
  options // The options
);

The app instance will be used to set up middleware and routes. The data source provides persistence for the OAuth 2.0 metadata models.

Server types

Two option properties indicate if you want to set up the OAuth 2.0 provider as an authorization server, a resource server, or both.

Property Type Description
authorizationServer Boolean If true, set up the authorization server.
resourceServer Boolean If true, set up the resource server.

Authorization server options

The following options are available for an authorization server:

Property Type Description Default
authorizePath String or
Boolean (only false) 		If String, specifies the path to mount the authorization endpoint. If false, do not set up the authorization endpoint. /oauth
/authorize
decisionPage String URL to the decision dialog page. Overrides decisionView. The query parameters are:
  • transactionId: An internal token to prevent forging
  • userId: user/resource owner ID
  • clientId: client application ID
  • scope: OAuth 2.0 scope(s)
  • redirectURI: redirect uri after the decision is made
  
decisionPath String or
Boolean (only false)		 If String, specifies the path to mount the decision endpoint. If false, do not set up the decision endpoint POST
/oauth
/authorize
/decision
decisionView String Server-side view name to render the decision dialog. The input for the view is:
  • transactionId: An internal token to prevent forging
  • user: user/resource owner object
  • client: client application object
  • scope: OAuth 2.0 scope(s)
  • redirectURI: redirect URI after the decision is made
  
loginPage String URL to the login dialog page. /login
loginPath String or
Boolean (only false)		 Path to mount the user login endpoint. POST /login
tokenPath String or
Boolean (only false)		 If String, specifies the path to mount the token endpoint. If false, do not set up the token endpoint POST /oauth/token

Supported grant types

The supportedGrantTypes option controls what grant types should be enabled:

  • supportedGrantTypes (string[])
    • default to [‘authorizationCode’, ‘implicit’, ‘clientCredentials’, ‘resourceOwnerPasswordCredentials’, ‘refreshToken’, ‘jwt’];

Custom functions for token generation

  • generateToken: function(options) returns a token string
  • getTTL: function(grantType, clientId, resourceOwner, scopes) returns a ttl number in seconds

Protect endpoints with OAuth 2.0

oauth2.authenticate(['/protected', '/api', '/me'], {
  session: false,
  scope: 'email'
});

Examples

See strong-gateway for an example of using OAuth2.0 with the StrongLoop API Gateway.