Clients: (v4.3)

A Client represents a web authentication mechanism. It performs the login process and returns (if successful) a user profile. Many clients are available for the:

• OAuth protocol
• SAML protocol
• CAS protocol
• OpenID Connect protocol
• HTTP protocol
• OpenID protocol
• Google App Engine support
• Kerberos (SPNEGO Negotiate) protocol

While most clients are self-sufficient, the HTTP clients require defining an Authenticator to handle the credentials validation.

Clients (like authorizers and matchers) are generally defined in a security configuration.

Each client has a name which is by default the class name (like FacebookClient), but it can be explicitly set to another value with the setName method.

Understanding the main features:

• Direct vs indirect clients
• Compute roles and permissions
• The callback URL
• Profile definition
• AJAX requests
• The Client methods
• The originally requested URL
• Silent login

1) Direct vs indirect clients

Clients are of two kinds: direct clients are for web services authentication and indirect clients are for UI authentication.

Here are their behaviors and differences:

2) Compute roles and permissions

To compute the appropriate roles and permissions of the authenticated user profile, you need to define an AuthorizationGenerator and attach it to the client.

Example:

AuthorizationGenerator authGen = (ctx, profile) -> {
  String roles = profile.getAttribute("roles");
  for (String role: roles.split(",")) {
    profile.addRole(role);
  }
  return Optional.of(profile);
};
client.addAuthorizationGenerator(authGen);

You can add as many authorization generators as you want using the addAuthorizationGenerator method or a list of authorization generators using the setAuthorizationGenerators method.

3) The callback URL

For an indirect client, you must define the callback URL which will be used in the login process: after a successful login, the identity provider will redirect the user back to the application on the callback URL.

On this callback URL, the “callback endpoint” must be defined to finish the login process.

As the callback URL can be shared between multiple clients, the callback URL must hold the information of the client (to be able to distinguish between the different clients), as a query parameter or as a path parameter.

Example:

FacebookClient facebookClient = new FacebookClient(fbKey, fbSecret);
TwitterClient twitterClient = new TwitterClient(twKey, twSecret);
Config config = new Config("http://localhost:8080/callback", facebookClient, twitterClient);

In this case, the callback URL of the FacebookClient is http://localhost:8080/callback?client_name=FacebookClient and the callback URL of the TwitterClient is http://localhost:8080/callback?client_name=TwitterClient.

This is the callback URL you must define on the identity provider side.

This happens because the default CallbackUrlResolver of the clients is the QueryParameterCallbackUrlResolver.

You can change the client_name parameter using the setClientNameParameter method of the QueryParameterCallbackUrlResolver.

But you can also use the PathParameterCallbackUrlResolver, which adds the client name as a path parameter.

Example:

OidcConfiguration configuration = new OidcConfiguration();
configuration.setClientId("788339d7-1c44-4732-97c9-134cb201f01f");
configuration.setSecret("we/31zi+JYa7zOugO4TbSw0hzn+hv2wmENO9AS3T84s=");
configuration.setDiscoveryURI("https://login.microsoftonline.com/38c46e5a-21f0-46e5-940d-3ca06fd1a330/.well-known/openid-configuration");
AzureAdClient azureAdClient = new AzureAdClient(configuration);
client.setCallbackUrlResolver(new PathParameterCallbackUrlResolver());
Clients clients = new Clients("http://localhost:8080/callback", azureAdClient);
Config config = new Config(clients);

In that case, the callback URL will be http://localhost:8080/callback/AzureAdClient for the AzureAdClient.

You may even use the NoParameterCallbackUrlResolver which left the callback URL untouched. In that case, no parameter will be added to the callback URL and no client will be retrieved on the callback endpoint. You will be forced to define a “default client” at the CallbackLogic level.

Example:

defaultCallbackLogic.setClient("FacebookClient");

The CallbackUrlResolver relies on a UrlResolver to complement the URL according to the current web context. The UrlResolver can be retrieved via the getUrlResolver() method of the client.

You can use the DefaultUrlResolver and handle relative URLs by using: defaultUrlResolver.setCompleteRelativeUrl(true). Or provide your own UrlResolver using the setUrlResolver method.

4) Profile definition

Most clients rely on the Authenticator and ProfileCreator components to validate credentials and create the user profile.

At the end of the login process, the returned user profile is created by the (internal) Authenticator or ProfileCreator, which holds a profile definition.

This profile definition can be overridden using the setProfileDefinition method.

5) AJAX requests

For an indirect client, if the user tries to access a protected URL, he will be redirected to the identity provider for login.

Though, if the incoming HTTP request is an AJAX one, no redirection will be performed and a 401 error page will be returned.

The HTTP request is considered to be an AJAX one if the value of the X-Requested-With header is XMLHttpRequest or if the is_ajax_request parameter or header is true. This is the behaviour of the DefaultAjaxRequestResolver.

The DefaultAjaxRequestResolver will only compute the redirection URL and add it as a header if the addRedirectionUrlAsHeader property is set to true.

But you can provide your own AjaxRequestResolver with: client.setAjaxRequestResolver(myAjaxRequestResolver);.

6) The Client methods

The Client interface has the following methods:

Clients are generally populated with default sub-components: RedirectionActionBuilder, CredentialsExtractor, ProfileCreator, LogoutActionBuilder and Authenticator, except for HTTP clients where the Authenticator must be explicitely defined. Sub-components can of course be changed for various customizations.

7) The originally requested URL

The originally requested URL is the URL called before the authenticated process starts: it is restored by the “callback endpoint” after the login process has been completed.

It is handled in the DefaultSecurityLogic and in the DefaultCallbackLogic by the SavedRequestHandler component. By default, it’s the DefaultSavedRequestHandler which handles GET and POST requests.

8) Silent login

When using an IndirectClient, the login process can fail or be cancelled at the external identity provider level.

Thus, no user profile is created and the access is not granted to the secured resources (401 error).

Though, you may still want to access the web resources if the login process has failed or been cancelled.

For that, you can return a custom profile instead of no profile by using the setProfileFactoryWhenNotAuthenticated method of the client.

Example:

myClient.setProfileFactoryWhenNotAuthenticated(p -> AnonymousProfile.INSTANCE);