src/main/java/org/eclipse/openk/auth2/util/JwtHelper.java

/*
 *******************************************************************************
 * Copyright (c) 2018 Contributors to the Eclipse Foundation
 *
 * See the NOTICE file(s) distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * SPDX-License-Identifier: EPL-2.0
 *******************************************************************************
*/

package org.eclipse.openk.auth2.util;

import com.google.gson.JsonSyntaxException;
import com.google.gson.reflect.TypeToken;
import org.apache.commons.codec.binary.Base64;
import org.apache.http.HttpStatus;
import org.apache.log4j.Logger;
import org.eclipse.openk.auth2.model.JwtPayload;
import org.eclipse.openk.auth2.model.KeyCloakUser;
import org.eclipse.openk.common.JsonGeneratorBase;
import org.eclipse.openk.core.exceptions.HttpStatusException;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Type;
import java.util.List;

public class JwtHelper {

  private static final Logger LOGGER = Logger.getLogger(JwtHelper.class.getName());

  private JwtHelper() {}

  public static JwtPayload getJwtPayload(String token) throws HttpStatusException {

      if (token != null && !token.isEmpty()) {
          String plainToken = JwtHelper.formatToken(token);
          String[] parts = plainToken.split("[.]");


          String jwtPayload = parts[1]; // we need only this here

          Base64 decoder = new Base64(true);
          byte[] decodedBytes = decoder.decode(jwtPayload);
          try {
              jwtPayload = new String(decodedBytes, "UTF-8" );
          } catch (UnsupportedEncodingException e) {
              LOGGER.error( "Unsupported encoding", e );
              jwtPayload = new String(decodedBytes );
          }

          return getJwtPayloadFromJson(jwtPayload);
      }
      else {
          throw new HttpStatusException(HttpStatus.SC_UNAUTHORIZED);
      }

  }

  public static JwtPayload getJwtPayloadFromJson(String json) {
    return org.eclipse.openk.common.JsonGeneratorBase.getGson().fromJson(json, JwtPayload.class);
  }

  public static List<KeyCloakUser> getUserListFromJson(String json) throws HttpStatusException {
    try {
      Type listType = new TypeToken<List<KeyCloakUser>>(){}.getType();
      return JsonGeneratorBase.getGson().fromJson(json, listType);
    } catch (JsonSyntaxException ex) {
      LOGGER.error("Error in getUserListFromJson", ex);
      throw new HttpStatusException(HttpStatus.SC_INTERNAL_SERVER_ERROR);
    }
  }

  public static String formatToken(String accessToken) {
    return accessToken != null ? accessToken.replace("Bearer", "").trim() : "";
  }

}