查看本类的 API文档回源码主页

   /*
    * Copyright 2017 The Netty Project
    *
    * The Netty Project licenses this file to you under the Apache License,
    * version 2.0 (the "License"); you may not use this file except in compliance
    * with the License. You may obtain a copy of the License at:
    *
    *   https://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations
   * under the License.
   */
  package io.netty.handler.ssl;
  
  import io.netty.buffer.ByteBuf;
  import io.netty.buffer.ByteBufAllocator;
  import io.netty.channel.ChannelHandler;
  import io.netty.channel.ChannelHandlerContext;
  import io.netty.handler.codec.ByteToMessageDecoder;
  import io.netty.util.ReferenceCountUtil;
  import io.netty.util.internal.ObjectUtil;
  
  import javax.net.ssl.SSLContext;
  import javax.net.ssl.SSLParameters;
  import java.util.List;
  
  /**
   * {@link OptionalSslHandler} is a utility decoder to support both SSL and non-SSL handlers
   * based on the first message received.
   */
  public class OptionalSslHandler extends ByteToMessageDecoder {
  
      private final SslContext sslContext;
  
      public OptionalSslHandler(SslContext sslContext) {
          this.sslContext = ObjectUtil.checkNotNull(sslContext, "sslContext");
      }
  
      @Override
      protected void decode(ChannelHandlerContext context, ByteBuf in, List<Object> out) throws Exception {
          if (in.readableBytes() < SslUtils.SSL_RECORD_HEADER_LENGTH) {
              return;
          }
          if (SslHandler.isEncrypted(in)) {
              handleSsl(context);
          } else {
              handleNonSsl(context);
          }
      }
  
      private void handleSsl(ChannelHandlerContext context) {
          SslHandler sslHandler = null;
          try {
              sslHandler = newSslHandler(context, sslContext);
              context.pipeline().replace(this, newSslHandlerName(), sslHandler);
              sslHandler = null;
          } finally {
              // Since the SslHandler was not inserted into the pipeline the ownership of the SSLEngine was not
              // transferred to the SslHandler.
              if (sslHandler != null) {
                  ReferenceCountUtil.safeRelease(sslHandler.engine());
              }
          }
      }
  
      private void handleNonSsl(ChannelHandlerContext context) {
          ChannelHandler handler = newNonSslHandler(context);
          if (handler != null) {
              context.pipeline().replace(this, newNonSslHandlerName(), handler);
          } else {
              context.pipeline().remove(this);
          }
      }
  
      /**
       * Optionally specify the SSL handler name, this method may return {@code null}.
       * @return the name of the SSL handler.
       */
      protected String newSslHandlerName() {
          return null;
      }
  
      /**
       * Override to configure the SslHandler eg. {@link SSLParameters#setEndpointIdentificationAlgorithm(String)}.
       * The hostname and port is not known by this method so servers may want to override this method and use the
       * {@link SslContext#newHandler(ByteBufAllocator, String, int)} variant.
       *
       * @param context the {@link ChannelHandlerContext} to use.
       * @param sslContext the {@link SSLContext} to use.
       * @return the {@link SslHandler} which will replace the {@link OptionalSslHandler} in the pipeline if the
       * traffic is SSL.
       */
      protected SslHandler newSslHandler(ChannelHandlerContext context, SslContext sslContext) {
          return sslContext.newHandler(context.alloc());
      }
  
     /**
      * Optionally specify the non-SSL handler name, this method may return {@code null}.
      * @return the name of the non-SSL handler.
      */
     protected String newNonSslHandlerName() {
         return null;
     }
 
     /**
      * Override to configure the ChannelHandler.
      * @param context the {@link ChannelHandlerContext} to use.
      * @return the {@link ChannelHandler} which will replace the {@link OptionalSslHandler} in the pipeline
      * or {@code null} to simply remove the {@link OptionalSslHandler} if the traffic is non-SSL.
      */
     protected ChannelHandler newNonSslHandler(ChannelHandlerContext context) {
         return null;
     }
 }