OAuth

npm version Changelog

$ npm install @feathersjs/authentication-oauth --save

@feathersjs/authentication-oauth allows to authenticate with over 180 oAuth providers (Google, Facebook, GitHub etc.) using grant, an oAuth middleware module for NodeJS.

Configuration

The following settings are available:

  • redirect: The URL of the frontend to redirect to with the access token (or error message). The authentication client handles those redirects automatically. If not set, the authentication result will be sent as JSON instead.
  • defaults: Default Grant configuration used for all strategies. The following default options are set automatically:
    • path (default: '/oauth') - The oAuth base path
  • <strategy-name> (e.g. twitter): The Grant configuration used for a specific strategy.
  • For both defaults and specific strategies, the following options are set automatically:
    • host: Set to host from the configuration
    • protocol: 'http' for development, 'https' for production (when NODE_ENV=production)
    • transport: Set to 'session' (see Grant response data)
    • callback: Set to '<defaults.path>/<name>/authenticate'. This should not be changed.

Pro tip: Removing the redirect setting is a good way to troubleshoot oAuth authentication errors.

Standard oAuth authentication can be configured with those options in config/default.json like this:

{
  "authentication": {
    "oauth": {
      "redirect": "/frontend",
      "google": {
        "key": "...",
        "secret": "...",
        "custom_params": { "access_type": "offline" }
      },
      "twitter": {
        "key": "...",
        "secret": "..."
      }
    }
  }
}

Note: All oAuth strategies will by default always look for configuration under authentication.oauth.<name>. If authentication.oauth is not set in the configuration, oAuth authentication will be disabled.

Here is a list of all Grant configuration options that are available:

Key Location Description
request_url oauth.json OAuth1/step1
authorize_url oauth.json OAuth1/step2 or OAuth2/step1
access_url oauth.json OAuth1/step3 or OAuth2/step2
oauth oauth.json OAuth version number
scope_delimiter oauth.json string delimiter used for concatenating multiple scopes
protocol, host, path defaults used to generate redirect_uri
transport defaults transport to use to deliver the response data in your final callback route
state defaults toggle random state string generation for OAuth2
key [provider] OAuth app key, reserved aliases: consumer_key and client_id
secret [provider] OAuth app secret, reserved aliases: consumer_secret and client_secret
scope [provider] list of scopes to request
custom_params [provider] custom authorization parameters and their values
subdomain [provider] string to be embedded in request_url, authorize_url and access_url
nonce [provider] toggle random nonce string generation for OpenID Connect providers
callback [provider] final callback route on your server to receive the response data
dynamic [provider] allow dynamic override of configuration
overrides [provider] static overrides for a provider
response [provider] limit the response data
token_endpoint_auth_method [provider] authentication method for the token endpoint
name generated provider's name, used to generate redirect_uri
profile_url grant-profile The URL to retrieve the user profile from
[provider] generated provider's name as key
redirect_uri generated OAuth app redirect URI, generated using protocol, host, path and name

Usage

Cookbook guides

For specific oAuth provider setup see the following cookbook guides:

Flow

There are two ways to initiate oAuth authentication:

  1. Through the browser (most common)

    • User clicks on link to oAuth URL (oauth/<provider>)
    • Gets redirected to provider and authorizes the application
    • Callback to the OauthStrategy which
      • Gets the users profile
      • Finds or creates the user (entity) for that profile
    • The AuthenticationService creates an access token for that entity
    • Redirect to the redirect URL including the generated access token
    • The frontend (e.g. authentication client) uses the returned access token to authenticate
  2. With an existing access token, e.g. obtained through the Facebook mobile SDK

    • Authenticate normally with { strategy: '<name>', access_token: 'oauth access token' }.
    • Calls the OauthStrategy which
      • Gets the users profile
      • Finds or creates the entity for that profile
    • Returns the authentication result

Note: If you are attempting to authenticate using an obtained access token, ensure that you have added the strategy (e.g. 'facebook') to your authStrategies.

oAuth URLs

There are several URLs and redirects that are important for oAuth authentication:

  • http(s)://<host>/oauth/<provider>: The main URL to initiate the oAuth flow. Link to this from the browser.
  • http(s)://<host>/oauth/<provider>/callback: The callback path that should be set in the oAuth application settings
  • http(s)://<host>/oauth/<provider>/authenticate: The internal redirect

In the browser any oAuth flow can be initiated with the following link:

<a href="/oauth/github">Login with GitHub</a>

Account linking

To link an existing user the current access token can be added to the oAuth flow query using the feathers_token query parameter:

<a href="/oauth/github?feathers_token=<your access token>">
  Login with GitHub
</a>

This will use the user (entity) of that access token to link the oAuth account to. Using the authentication client you can get the current access token via app.get('authentication'):

const { accessToken } = await app.get('authentication');

Redirects

The redirect configuration option is used to redirect back to the frontend application after oAuth authentication was successful and an access token for the user has been created by the authentication service or if authentication failed. It works cross domain and by default includes the access token or error message in the window location hash. The following configuration

{
  "authentication": {
    "oauth": {
      "redirect": "https://app.mydomain.com/"
    }
  }
}

Will redirect to https://app.mydomain.com/#access_token=<user jwt> or https://app.mydomain.com/#error=<some error message>. Redirects can be customized with the getRedirect() method of the oAuth strategy. The authentication client handles the default redirects automatically already.

Note: The redirect is using a hash instead of a query string by default because it is not logged server side and can be easily read on the client. You can force query based redirect by adding a ? to the end of the redirect option.

If the redirect option is not set, the authentication result data will be sent as JSON instead.

Dynamic redirects to the same URL are possible by setting the redirect query parameter in the oAuth flow. For example, the following oAuth link:

<a href="/oauth/github?redirect=dashboard">
  Login with GitHub
</a>

With the above configuration will redirect to https://app.mydomain.com/dashboard after the oAuth flow.

Setup (Express)

expressOauth (for setup see the AuthenticationService) sets up oAuth authentication on a Feathers Express application and can take the following options:

  • authService: The name of the authentication service
  • linkStrategy (default: 'jwt'): The name of the strategy to use for account linking
  • expressSession (default: require('express-session')()): The Express session middleware to use. Uses in-memory sessions by default but may need to be customized to a persistent storage when using multiple instances of the application. Other sessions stores can be used by settin g the expressSession option using a different memory store, e.g. connect-redis in the authentication configuration:
const redis = require('redis')
const session = require('express-session')
const { expressOauth } = require('@feathersjs/authentication-oauth');

const RedisStore = require('connect-redis')(session)
const redisClient = redis.createClient()

app.configure(expressOauth({
  expressSession: session({
    store: new RedisStore({ client: redisClient }),
    secret: 'keyboard cat',
    resave: false,
  })
}));

Important: If not customized, Express oAuth uses the in-memory Express session store which will show a connect.session() MemoryStore is not designed for a production environment, as it will leak memory, and will not scale past a single process. warning in production.

OAuthStrategy

entityId

oauthStrategy.entityId -> string returns the name of the id property of the entity.

getEntityQuery(profile, params)

oauthStrategy.getEntityQuery(profile, params) -> Promise returns the entity lookup query to find the entity for a profile. By default returns

{
  [`${this.name}Id`]: profile.sub || profile.id
}

getEntityData(profile, entity, params)

oauthStrategy.getEntityData(profile, existing, params) -> Promise returns the data to either create a new or update an existing entity. entity is either the existing entity or null when creating a new entity.

getProfile(data, params)

oauthStrategy.getProfile(data, params) -> Promise returns the user profile information from the oAuth provider that was used for the login. data is the oAuth callback information which normally contains e.g. the oAuth access token.

getRedirect (data)

oauthStrategy.getRedirect(data) -> Promise returns the URL to redirect to after a successful oAuth login and entity lookup or creation. By default it redirects to authentication.oauth.redirect from the configuration with #access_token=<access token for entity> added to the end of the URL. The access_token hash is e.g. used by the authentication client to log the user in after a successful oAuth login. The default redirects do work cross domain.

getCurrentEntity(params)

oauthStrategy.getCurrentEntity(params) -> Promise returns the currently linked entity for the given params. It will either use the entity authenticated by params.authentication or return null.

findEntity(profile, params)

oauthStrategy.findEntity(profile, params) -> Promise finds an entity for a given oAuth profile. Uses { [${this.name}Id]: profile.id } by default.

createEntity(profile, params)

oauthStrategy.createEntity(profile, params) -> Promise creates a new entity for the given oAuth profile. Uses { [${this.name}Id]: profile.id } by default.

updateEntity(entity, profile, params)

oauthStrategy.updateEntity(entity, profile, params) -> Promise updates an existing entity with the given profile. Uses { [${this.name}Id]: profile.id } by default.

authenticate(authentication, params)

oauthStrategy.authenticate(authentication, params) is the main endpoint implemented by any authentication strategy. It is usually called for authentication requests for this strategy by the AuthenticationService.

Customization

Normally, any oAuth provider set up in the configuration will be initialized with the default OAuthStrategy. The flow for a specific provider can be customized by extending OAuthStrategy class and registering it under that name on the AuthenticationService: