Facebook Authenticator

The Facebook authenticator provides the ability for users to login using Facebook. The integration to Facebook is done using OAuth 2. To use it, you need to configure a OAuth 2 client in Facebook, and then configure a Facebook authenticator instance in the Authentication Service. The steps to do this are described below.

Configuring Facebook

To use Facebook accounts in the Authentication Service, you need to register a Facebook app. To do this, sign into Facebook, register as a developer, and create a new new app at https://developers.facebook.com/.

Create a New Project

After logging into Facebook for Developer, click on My Apps in the top navigation bar. Then click Create App.

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Fig. 67 Facebook - Start screen

In the Create an App screen, select an App Type, for example None. Then click Next

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Fig. 68 Facebook - Select App Type

Then, enter a Display name (e.g., CurityLogin) and an App contact email, then click the Create app button.

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Fig. 69 Facebook - Create new Facebook app

In the panel to the left, select Setting -> Basic. Facebook has generated credentials for the authenticator. The App ID in Facebook will correspond to the client_id in the Authentication Service, and Facebook’s App secret will be used as the client_secret. To access this secret key, click the Show button.

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Fig. 70 Facebook - App ID and App Secret

The Redirect URI

The redirect URI is the URI where Facebook will redirect the user when the authentication is done. The URI that the Authentication Service uses is generated automatically based on configuration, and is the path to the authenticator with an added /callback. This last part of the path is only used in the communication between the Authentication Service and Facebook, and can not be changed whereas the preceding components of the path can be.

The form is like this:

<base-url>/<authentication-endpoint>/<authenticator-id>/callback

For example, for a server running on server1.local and a protocol of https and listening on port 8443 and having an authentication endpoint configured to be /authn/authenticate and with a Facebook authenticator instance called facebook1, the redirect URI would be:

https://server1.local:8443/authn/authenticate/facebook1/callback

Set the Redirect URI

This redirect URI needs to be set in Facebook. To do so, find that app that you previously created (e.g., CurityLogin), and click Settings -> Advanced in the panel on the left then scroll down to the bottom.

In the Share Redirect Allow List section, add the redirect URI(s).

Important

Press enter in order for the redirect URI to be added to the field.

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Fig. 71 Facebook - Redirect URI

Finally, click Save Changes.

The App is now registered and can be used in the Authentication Service.

Configuration in the Authentication Service

The general authenticator configuration is described under Authenticator Base Configuration. This section describes the additional parameters that are available for the Facebook authenticator.

Important

Authenticator base is /profiles/profile{id type}/settings/authentication-service/authenticators/

List Entry: <authenticator_base>/authenticator/ (key id)

client_id: The OAuth2 client ID that is registered at Facebook

type string

mandatory

client_secret: The OAuth2 client secret that is registered at Facebook

type string

mandatory

scope: The scope to ask Facebook for, space separated

type string

default public_profile email

authorization-endpoint: URL to the Facebook authorization endpoint

type string

default https://www.facebook.com/dialog/oauth

token-endpoint: URL to the Facebook token endpoint

type string

default https://graph.facebook.com/v2.3/oauth/access_token

userinfo-endpoint: URL to the Facebook userinfo endpoint

type string

default https://graph.facebook.com/v2.2/me

Example:

<authenticator xmlns="https://curity.se/ns/conf/profile/authentication">
    <id>facebook1</id>
    <facebook xmlns="https://curity.se/ns/conf/authenticators/facebook">
        <client-secret>123456778912345677890012345677890</client-secret>
        <client-id>1234567890</client-id>
    </facebook>
</authenticator>