content: /*
   * Copyright (c) 2019 abc123lzf <abc123lzf@126.com>
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  package com.lzf.flyingsocks.client.proxy.socks;
  
  import io.netty.channel.ChannelPipeline;
  import org.apache.commons.lang3.StringUtils;
  
  /**
   * Socks5 客户端认证策略
   *
   * @author lzf abc123lzf@126.com
   * @since 2021/1/22 15:20
   */
  interface AuthenticationStrategy {
  
      /**
       * 执行认证
       *
       * @param username 用户名
       * @param password 密码
       * @return 认证是否通过
       */
      boolean grantAuthorization(String username, String password);
  
      /**
       * 认证通过后对管道的操作
       * 目前预留，方便日后扩展
       *
       * @param pipeline 当前Socks5客户端连接管道对象
       * @param username 用户名
       */
      default void afterAuthorizationSuccess(ChannelPipeline pipeline, String username) { }
  
  }
  
  
  /**
   * 简易认证策略，使用固定的用户名和密码
   */
  class SimpleAuthenticationStrategy implements AuthenticationStrategy {
  
      private final String username;
  
      private final String password;
  
      SimpleAuthenticationStrategy(String username, String password) {
          if (StringUtils.isAnyBlank(username, password)) {
              throw new IllegalArgumentException("Username or password is blank");
          }
  
          this.username = username;
          this.password = password;
      }
  
      @Override
      public boolean grantAuthorization(String username, String password) {
          return this.username.equals(username) && this.password.equals(password);
      }
  }