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Resource Server Implementation in Java

Overview

This is a resource server implementation in Java. It supports a userinfo endpoint defined in OpenID Connect Core 1.0 and includes an example of a protected resource endpoint that accepts an access token in the ways defined in RFC 6750 (The OAuth 2.0 Authorization Framework: Bearer Token Usage).

This implementation is written using JAX-RS 2.0 API and authlete-java-jaxrs library. JAX-RS is The Java API for RESTful Web Services. JAX-RS 2.0 API has been standardized by JSR 339 and it is included in Java EE 7. On the other hand, authlete-java-jaxrs library is an open source library which provides utility classes for developers to implement an authorization server and a resource server. authlete-java-jaxrs in turn uses authlete-java-common library which is another open source library to communicate with Authlete Web APIs.

To validate an access token presented by a client application, this resource server makes an inquiry to the Authlete server. This means that this resource server expects that the authorization server which has issued the access token uses Authlete as a backend service. java-oauth-server is such an authorization server implementation and it supports OAuth 2.0 and OpenID Connect.

License

Apache License, Version 2.0

Source Code

<code>https://github.com/authlete/java-resource-server</code>

About Authlete

Authlete is a cloud service that provides an implementation of OAuth 2.0 & OpenID Connect (overview). You can easily get the functionalities of OAuth 2.0 and OpenID Connect either by using the default implementation provided by Authlete or by implementing your own authorization server using Authlete Web APIs as java-oauth-server does.

To use this resource server implementation, you need to get API credentials from Authlete and set them in authlete.properties. The steps to get API credentials are very easy. All you have to do is just to register your account (sign up). See Getting Started for details.

How To Run

1. Download the source code of this resource server implementation.

    $ git clone https://github.com/authlete/java-resource-server.git
    $ cd java-resource-server
   

2. Edit the configuration file to set the API credentials of yours.

    $ vi authlete.properties
   

3. Make sure that you have installed maven and set JAVA_HOME properly.

4. Start the resource server on http://localhost:8081/.

    $ mvn jetty:run &
   

Run With Docker

If you would prefer to use Docker, just hit the following command after the step 2.

$ docker-compose up

Configuration File

java-resource-server refers to authlete.properties as a configuration file. If you want to use another different file, specify the name of the file by the system property authlete.configuration.file like the following.

$ mvn -Dauthlete.configuration.file=local.authlete.properties jetty:run &

Endpoints

This implementation exposes endpoints as listed in the table below.

UserInfo Endpoint

The userinfo endpoint is an implementation of the requirements described in 5.3. UserInfo Endpoint of OpenID Connect Core 1.0.

The endpoint accepts an access token as a Bearer Token. That is, it accepts an access token via Authorization: Bearer {access-token} or by a request parameter access_token={access-token}. See RFC 6750 for details.

The endpoint returns user information in JSON or JWT format, depending on the configuration of the client application. If both userinfo_signed_response_alg and userinfo_encrypted_response_alg of the metadata of the client application are not specified, user information is returned as a plain JSON. Otherwise, it is returned as a serialized JWT. Authlete provides you with a Web console (Developer Console) to manage metadata of client applications. As for metadata of client applications, see 2. Client Metadata in OpenID Connect Dynamic Client Registration 1.0.

User information returned from the endpoint contains claims of the user. In short, claims are pieces of information about the user such as a given name and an email address. Because Authlete does not manage user data (although it supports OpenID Connect), you have to provide claim values. It is achieved by implementing UserInfoRequestHandlerSpi interface.

In this resource server implementation, UserInfoRequestHandlerSpiImpl is an example implementation of UserInfoRequestHandlerSpi interface and it retrieves claim values from a dummy database. You need to modify the implementation to make it refer to your actual user database.

NOTE (May 1, 2022)

A userinfo endpoint was implemented in java-oauth-server. The userinfo endpoint implemented in java-resource-server is no longer maintained.

The userinfo endpoint implementation in java-oauth-server correctly implements the filtering rules and the data minimization policy of OpenID Connect for Identity Assurance 1.0 and supports Transformed Claims defined in OpenID Connect Advanced Syntax for Claims 1.0.

Country Endpoint

The country endpoint implemented in this resource server is just an example of a protected resource endpoint. Its main purpose is to show how to validate an access token at a protected resource endpoint. To be concrete, the purpose is to show usage of extractAccessToken method and validateAccessToken method defined in BaseResourceEndpoint class.

The path of the country endpoint is /api/country/{country-code} where {country-code} is an ISO 3166-1 code (alpha-2, alpha-3, or numeric). For example, JP, JPN and 392 are valid ISO 3166-1 codes and all of them represent Japan. Therefore, the following URL is a valid request to the country endpoint.

http://localhost:8081/api/country/JP?access_token={access-token}

The response from the endpoint is JSON that contains the following information about the country identified by the {country-code}.

1. Country name
2. ISO 3166-1 alpha-2 code
3. ISO 3166-1 alpha-3 code
4. ISO 3166-1 numeric code
5. Currency

The following is an example response.

{
  "name": "Japan",
  "alpha2": "JP",
  "alpha3": "JPN",
  "numeric": 392,
  "currency": "JPY"
}

As for generic and Authlete-specific information regarding how to protect Web APIs by OAuth access tokens, see Protected Resource in Authlete Definitive Guide.

Customization

The simplest way to add a new protected resource endpoint is to create a subclass of BaseResourceEndpoint as CountryEndpoint does. However, of course, it is okay for you to use AccessTokenValidator (in authlete-java-jaxrs) or call AuthleteApi.introspection(IntrospectionRequest) API (in authlete-java-common) directly.

As you add new protected resource endpoints, you will want to add new scopes. Use Service Owner Console to add new scopes for your Web APIs.

See Also

• Authlete - Authlete Home Page
• authlete-java-common - Authlete Common Library for Java
• authlete-java-jaxrs - Authlete Library for JAX-RS (Java)
• java-oauth-server - Authorization Server Implementation

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