Custom APIMTokenIssuer Implementation: Append Custom Value to the Generated Access Token

MyAPIMTokenIssuer.java

package com.sample.token;

import org.apache.oltu.oauth2.common.exception.OAuthSystemException;
import org.wso2.carbon.apimgt.api.APIManagementException;
import org.wso2.carbon.apimgt.api.model.Application;
import org.wso2.carbon.apimgt.impl.APIConstants;
import org.wso2.carbon.apimgt.impl.utils.APIUtil;
import org.wso2.carbon.apimgt.keymgt.issuers.APIMTokenIssuer;
import org.wso2.carbon.identity.oauth2.token.OAuthTokenReqMessageContext;
import org.wso2.carbon.identity.oauth2.model.RequestParameter;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class MyAPIMTokenIssuer extends APIMTokenIssuer {

	private static final Log log = LogFactory.getLog(MyAPIMTokenIssuer.class);

	@Override
	public String accessToken(OAuthTokenReqMessageContext tokReqMsgCtx) throws OAuthSystemException {

		// generate access token using super method
		String accessToken = super.accessToken(tokReqMsgCtx);

		String clientId = tokReqMsgCtx.getOauth2AccessTokenReqDTO().getClientId();
		Application application;
		try {
			application = APIUtil.getApplicationByClientId(clientId);
			String tokenType = application.getTokenType();

			// only acceptable for opaque access tokens and not JWT tokens
			if (!APIConstants.JWT.equals(tokenType)) {
				
				// retrieve all request parameters sent to the token request
				RequestParameter[] reqParams = tokReqMsgCtx.getOauth2AccessTokenReqDTO().getRequestParameters();
				for (int i = 0; i < reqParams.length; i++) {

					// check for devhash parameter from the request parameters and append it to the
					// access token
					if ("devhash".equals(reqParams[i].getKey())) {
						accessToken += reqParams[i].getValue()[0];
						break;
					}
				}
			}
		} catch (APIManagementException e) {
			log.error("Exception occured in my piece of code ", e);
		}

		return accessToken;
	}
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.sample.token</groupId>
	<artifactId>custom-token-issuer</artifactId>
	<version>1.0.0</version>

	<!-- change the packaging to bundle (from jar) to support OSGi -->
	<packaging>jar</packaging>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<maven.compiler.source>1.8</maven.compiler.source>
		<maven.compiler.target>1.8</maven.compiler.target>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.wso2.carbon.apimgt</groupId>
			<artifactId>org.wso2.carbon.apimgt.keymgt</artifactId>
			<version>6.5.222</version>
		</dependency>
 </dependencies>

	<repositories>
		<repository>
			<id>wso2-nexus</id>
			<url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
			<releases>
				<enabled>true</enabled>
				<updatePolicy>daily</updatePolicy>
				<checksumPolicy>ignore</checksumPolicy>
			</releases>
		</repository>
	</repositories>

	<pluginRepositories>
		<pluginRepository>
			<id>wso2-nexus</id>
			<url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
			<releases>
				<enabled>true</enabled>
				<updatePolicy>daily</updatePolicy>
				<checksumPolicy>ignore</checksumPolicy>
			</releases>
		</pluginRepository>
	</pluginRepositories>

	<build>
		<plugins>

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>2.0</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
				</configuration>
			</plugin>

			<!-- build plugin for OSGi Bundle support -->
			<plugin>
				<groupId>org.apache.felix</groupId>
				<artifactId>maven-bundle-plugin</artifactId>
				<version>2.3.4</version>
				<extensions>true</extensions>
				<configuration>
					<instructions>
						<Bundle-SymbolicName>com.sample.token</Bundle-SymbolicName>
						<Bundle-Name>com.sample.token</Bundle-Name>
						<Export-Package>
                            com.sample.token.*,
						</Export-Package>
						<Import-Package>
                            *; resolution:=optional
						</Import-Package>
					</instructions>
				</configuration>
			</plugin>

		</plugins>
	</build>
</project>