Capital One built this project to help our engineers as well as users in the community. We are no longer able to fully support the project. We have archived the project as of Jul 9 2019 where it will be available in a read-only state. Feel free to fork the project and maintain your own version.

Java Auth Client Library

Links
Overview
Obtaining OAuth Token
Maintaining OAuth Token Lifecycle
Example Usage
Contributors
Copyright

Overview

Supports OAuth authentication and provides interfaces to add more authentication methods.

Conceptually, the library has two parts:

Obtaining the OAuth token
Maintaining OAuth token lifecycle

Obtaining the OAuth token

OAuthClientCredentials is at the base of obtaining a token. It holds the information about the client requesting the app. This is:

grantType (Type of grant that is being requested)
clientId (ID of your app)
clientSecret (Secret of your app)

This class also holds other bits of information like the URL of the authorisation server (authURI) and the regular expression pattern (clientURIRegex) to match the client URIs needing the authorisation.

Suppose you have two URIs - one http://awesomeserver.com/hello and http://coolserver.com/hello being the other. If both of these require authorisation from the same server and if that authorisation can be fulfilled with the same set of client credentials, then you only need one instance of OAuthClientCredentials class but with a regular expression in clientURIRegex that can match both of those URIs. Howeever, if both of those URIs require different set of client credentials or a different authorisation server or both, then you need two separate instances.

Once you have one or more instances of OAuthClientCredentials class, create an instance of ClientCredentialsProvider class with type OAuthClientCredentials. This class needs at least one instance of the OAuthClientCredentials and thus requires it to be passed in the constructor.

The ClientCredentialsProvider, as the name suggests provides the credentials upon request. When getClientCredentialsFor is invoked with a URI, it loops through all of its OAuthClientCredentials objects and runs the clientURIRegex match against the given URI. It returns the first OAuthClientCredentials that matches the URI.

Once you have a working instance of ClientCredentialsProvider, create an instance of OAuthTokenService. The constructor needs the following:

httpConnectionFactory (Factory generating your HTTP connections)
httpConnectionConfig (Configuration for your HTTP connections. This includes sslProtocol, which defaults to TLSv1.2)
prefetchPoolSize (Size of your prefetch pool - more on this later)
oAuthClientCredentialsProvider (Your OAuthClientCredentials provider instance)

When requesting the token for the first time (using obtainTokenFor), the service simply returns the OAuthToken object as Token.

Maintaining OAuth token lifecycle

The Token object is cached as soon as it is returned for the first time. When a request comes for the next time and if the token has not expired, it simply returns the cached token.

However, if the token has certain amount of time left (defined in prefetchTimeout) before expiry, the token service fires off a prefetch job which asynchronously updates the token. All requests coming in during this time period use the token that has been cached and is about to expire. Once the asynchronous job returns a valid token, the current token is replaced with that token which is then returned to all subsequent requests.

If the requests have slowed down and the OAuthTokenService didn't get a chance to update the token asynchronously, it simply blocks the current request thread and gets the token synchronously (which it then caches).

Example Usage

Include the following in your gradle file. Make sure you replace $version what whatever version of the library you want to use.

dependencies {
    compile 'com.capitalone.util:c1-oauth-client-java:$version'
}

Here's an example client application using the library in action:

package com.capitalone.auth.example;

import com.capitalone.auth.ClientCredentialsProvider;
import com.capitalone.auth.TokenService;
import com.capitalone.auth.oauth.factory.HttpConnectionConfig;
import com.capitalone.auth.oauth.factory.HttpConnectionFactory;
import com.capitalone.auth.oauth.factory.HttpConnectionFactoryImpl;
import com.capitalone.auth.oauth.framework.OAuthClientCredentials;
import com.capitalone.auth.oauth.framework.OAuthClientCredentialsProvider;
import com.capitalone.auth.oauth.service.ClientSecretException;
import com.capitalone.auth.oauth.service.ClientSecretService;
import com.capitalone.auth.oauth.service.OAuthToken;
import com.capitalone.auth.oauth.service.OAuthTokenService;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.concurrent.locks.ReentrantLock;

public class ExampleClient {

    private final TokenService oAuthTokenService;

    public static void main(String[] args) {
        ExampleClient client = new ExampleClient();
        client.makeRequest();
    }

    public ExampleClient() {
        URI authServerURI = null;

        try {
            authServerURI = new URI("https://myoauthserver.com/oauth/oauth20/token");
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }

        OAuthClientCredentials builtClientCredentials = OAuthClientCredentials.newBuilder()
                .clientId("my_client_id")
                .clientSecret("my_client_secret")
                .clientSecretEncryptionKey(null)
                .clientURIRegex(".*")
                .grantType("client_credentials")
                .authServerURI(authServerURI)
                .build();

        ClientCredentialsProvider<OAuthClientCredentials> clientCredentialsProvider = new OAuthClientCredentialsProvider(builtClientCredentials);

        ClientSecretService clientSecretService = new DummyClientSecretService();

        HttpConnectionFactory httpConnectionFactory = new HttpConnectionFactoryImpl(new ReentrantLock());

        HttpConnectionConfig httpConnectionConfig = HttpConnectionConfig.newBuilder()
                .httpConnectionTimeout(60000)
                .httpSocketTimeout(40000)
                .maxHttpConnections(20)
                .sslProtocol("TLSv1.2")
                .build();

        oAuthTokenService = new OAuthTokenService(httpConnectionFactory, httpConnectionConfig, 20, 10, clientCredentialsProvider, clientSecretService);
    }

    public void makeRequest() {
        try {
            OAuthToken token = (OAuthToken) oAuthTokenService.obtainTokenFor(new URI("https://myoauthserver.com/partners/sparkpost/transmissions"));
            System.out.println(token.getValue());
        } catch (IOException | URISyntaxException e) {
            e.printStackTrace();
        }
    }

    private class DummyClientSecretService implements ClientSecretService {
        @Override
        public String obtainClientSecret(OAuthClientCredentials clientCredentials) throws ClientSecretException {
            if (null == clientCredentials.getClientSecretEncryptionKey()) {
                return clientCredentials.getClientSecret();
            } else {
                return decryptSecret(clientCredentials.getClientSecretEncryptionKey(), clientCredentials.getClientSecret());
            }
        }

        private String decryptSecret(String encryptionKey, String encryptedClientSecret) {
            return "abc1";
        }
    }
}

Dependencies

Library	Version	License
commons-io:commons-io	2.4	Apache 2.0
org.apache.httpcomponents:httpclient	4.5.2	Apache 2.0
com.fasterxml.jackson.core:jackson-databind	2.3.4	Apache 2.0
commons-lang:commons-lang	2.6	Apache 2.0
junit:junit	4.11	CAPL 1.0, CPL 1.0
org.mockito:mockito-core	1.10.19	MIT
org.hamcrest:hamcrest-all	1.3	BSD 2 -clause

Contributors

We welcome your interest in Capital One's Open Source Projects (the "Project"). Any Contributor to the project must accept and sign a CLA indicating agreement to the license terms. Except for the license granted in this CLA to Capital One and to recipients of software distributed by Capital One, you reserve all right, title, and interest in and to your contributions; this CLA does not impact your rights to use your own contributions for any other purpose.

Link to CLA

Link to Corporate Agreement

This project adheres to the Open Source Code of Conduct. By participating, you are expected to honor this code.

capitalone/OAuthClient