Netty处理HTTP之GET,POST请求

Love The Way You Lie 2022-08-22 00:25 519阅读 0赞

这里使用浏览器发出http请求，也可以使用netty写http的客户端。从浏览器请求http://localhost:8080/，服务器会生成两个form表单，一个form表单是get请求，一个是post请求，经过netty的request解码器，封装成HttpObject对象，判断对象是否是HttpRequest对象，是的话执行代码。

注：浏览器发出的/favicon.ico请求

浏览器调用favicon的原理是首先在网页所在目录寻找favicon.ico文件，如果没有找到就去网站的根目录寻找。所以最简单的方法就是将制作好的favicon文件命名为favicon.ico然后上传到网站的根目录下。

Netty的http对象都是Netty自己封装的，不是标准的。

1、先看http的服务器端。服务器的代码一般就是这样。

package org.nepu.httpgetpost;
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.channel.Channel;
    import io.netty.channel.EventLoopGroup;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.nio.NioServerSocketChannel;
    
    public class HttpDemoServer {
    	private final int port;
        public static boolean isSSL;
    
        public HttpDemoServer(int port) {
            this.port = port;
        }
    
        public void run() throws Exception {
            EventLoopGroup bossGroup = new NioEventLoopGroup(1);
            EventLoopGroup workerGroup = new NioEventLoopGroup();
            try {
                ServerBootstrap b = new ServerBootstrap();
                b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
                        .childHandler(new HttpDemoServerInitializer());
    
                Channel ch = b.bind(port).sync().channel();
                System.out.println("HTTP Upload Server at port " + port + '.');
                System.out.println("Open your browser and navigate to http://localhost:" + port + '/');
    
                ch.closeFuture().sync();
            } finally {
                bossGroup.shutdownGracefully();
                workerGroup.shutdownGracefully();
            }
        }
    
        public static void main(String[] args) throws Exception {
            int port;
            if (args.length > 0) {
                port = Integer.parseInt(args[0]);
            } else {
                port = 8080;
            }
            if (args.length > 1) {
                isSSL = true;
            }
            new HttpDemoServer(port).run();
        }
    }

2、初始化服务器端handler的代码

package org.nepu.httpgetpost;
    
    import io.netty.channel.ChannelInitializer;
    import io.netty.channel.ChannelPipeline;
    import io.netty.channel.socket.SocketChannel;
    import io.netty.example.securechat.SecureChatSslContextFactory;
    import io.netty.handler.codec.http.HttpContentCompressor;
    import io.netty.handler.codec.http.HttpRequestDecoder;
    import io.netty.handler.codec.http.HttpResponseEncoder;
    import io.netty.handler.ssl.SslHandler;
    
    
    
    import javax.net.ssl.SSLEngine;
    
    public class HttpDemoServerInitializer extends ChannelInitializer<SocketChannel> {
        @Override
        public void initChannel(SocketChannel ch) throws Exception {
            // Create a default pipeline implementation.
            ChannelPipeline pipeline = ch.pipeline();
    
            if (HttpDemoServer.isSSL) {
                SSLEngine engine = SecureChatSslContextFactory.getServerContext().createSSLEngine();
                engine.setUseClientMode(false);
                pipeline.addLast("ssl", new SslHandler(engine));
            }
    
            /**
             * http-request解码器
             * http服务器端对request解码
             */
            pipeline.addLast("decoder", new HttpRequestDecoder());
            /**
             * http-response解码器
             * http服务器端对response编码
             */
            pipeline.addLast("encoder", new HttpResponseEncoder());
    
            /**
             * 压缩
             * Compresses an HttpMessage and an HttpContent in gzip or deflate encoding
             * while respecting the "Accept-Encoding" header.
             * If there is no matching encoding, no compression is done.
             */
            pipeline.addLast("deflater", new HttpContentCompressor());
    
            pipeline.addLast("handler", new HttpDemoServerHandler());
        }
    }

3、最重要的是handler，处理http请求，返回http响应（返回响应给浏览器）

package org.nepu.httpgetpost;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.channel.*;
    import io.netty.handler.codec.http.*;
    import io.netty.handler.codec.http.multipart.*;
    import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.EndOfDataDecoderException;
    import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.ErrorDataDecoderException;
    import io.netty.handler.codec.http.multipart.InterfaceHttpData.HttpDataType;
    import io.netty.util.CharsetUtil;
    
    import java.io.IOException;
    import java.net.URI;
    import java.util.Collections;
    import java.util.List;
    import java.util.Map;
    import java.util.Map.Entry;
    import java.util.Set;
    
    import static io.netty.buffer.Unpooled.copiedBuffer;
    import static io.netty.handler.codec.http.HttpHeaders.Names.*;
    
    public class HttpDemoServerHandler extends SimpleChannelInboundHandler<HttpObject> {
    
        private HttpRequest request;
    
        private boolean readingChunks;
    
        private final StringBuilder responseContent = new StringBuilder();
    
        private static final HttpDataFactory factory = new DefaultHttpDataFactory(DefaultHttpDataFactory.MINSIZE); //Disk
    
        private HttpPostRequestDecoder decoder;
    
        @Override
        public void channelInactive(ChannelHandlerContext ctx) throws Exception {
            if (decoder != null) {
                decoder.cleanFiles();
            }
        }
    
        public void messageReceived(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
    
            System.err.println(msg.getClass().getName());
            /**
             * msg的类型
             * {@link DefaultHttpRequest}
             * {@link LastHttpContent}
             */
            if (msg instanceof HttpRequest) {
                HttpRequest request = this.request = (HttpRequest) msg;
                URI uri = new URI(request.getUri());
                System.err.println("request uri==" + uri.getPath());
    
                if (uri.getPath().equals("/favicon.ico")) {
                    return;
                }
                if (uri.getPath().equals("/")) {
                    writeMenu(ctx);
                    return;
                }
                responseContent.setLength(0);
                responseContent.append("WELCOME TO THE WILD WILD WEB SERVER\r\n");
                responseContent.append("===================================\r\n");
    
                responseContent.append("VERSION: " + request.getProtocolVersion().text() + "\r\n");
    
                responseContent.append("REQUEST_URI: " + request.getUri() + "\r\n\r\n");
                responseContent.append("\r\n\r\n");
    
                // new getMethod
                for (Entry<String, String> entry : request.headers()) {
                    responseContent.append("HEADER: " + entry.getKey() + '=' + entry.getValue() + "\r\n");
                }
                responseContent.append("\r\n\r\n");
    
                // new getMethod
                Set<Cookie> cookies;
                String value = request.headers().get(COOKIE);
                if (value == null) {
                    /**
                     * Returns an empty set (immutable).
                     */
                    cookies = Collections.emptySet();
                } else {
                    cookies = CookieDecoder.decode(value);
                }
                for (Cookie cookie : cookies) {
                    responseContent.append("COOKIE: " + cookie.toString() + "\r\n");
                }
                responseContent.append("\r\n\r\n");
    
                /**
                 * List<String>表示当参数相同时，把相同的参数的值放在list中
                 */
                QueryStringDecoder decoderQuery = new QueryStringDecoder(request.getUri());
                Map<String, List<String>> uriAttributes = decoderQuery.parameters();
                for (Entry<String, List<String>> attr : uriAttributes.entrySet()) {
                    for (String attrVal : attr.getValue()) {
                        responseContent.append("URI: " + attr.getKey() + '=' + attrVal + "\r\n");
                    }
                }
                responseContent.append("\r\n\r\n");
    
                // if GET Method: should not try to create a HttpPostRequestDecoder
                if (request.getMethod().equals(HttpMethod.GET)) {
                    // GET Method: should not try to create a HttpPostRequestDecoder
                    // So stop here
                    responseContent.append("\r\n\r\nEND OF GET CONTENT\r\n");
                    writeResponse(ctx.channel());
                    return;
                }
    
    
                //判断request请求是否是post请求
                if (request.getMethod().equals(HttpMethod.POST)) {
                    System.err.println("===this is http post===");
                    try {
                        /**
                         * 通过HttpDataFactory和request构造解码器
                         */
                        decoder = new HttpPostRequestDecoder(factory, request);
                    } catch (ErrorDataDecoderException e1) {
                        e1.printStackTrace();
                        responseContent.append(e1.getMessage());
                        writeResponse(ctx.channel());
                        ctx.channel().close();
                        return;
                    }
    
                    readingChunks = HttpHeaders.isTransferEncodingChunked(request);
                    responseContent.append("Is Chunked: " + readingChunks + "\r\n");
                    responseContent.append("IsMultipart: " + decoder.isMultipart() + "\r\n");
                    if (readingChunks) {
                        // Chunk version
                        responseContent.append("Chunks: ");
                        readingChunks = true;
                    }
                }
            }
    
            if (decoder != null) {
                if (msg instanceof HttpContent) {
                    // New chunk is received
                    HttpContent chunk = (HttpContent) msg;
                    try {
                        decoder.offer(chunk);
                    } catch (ErrorDataDecoderException e1) {
                        e1.printStackTrace();
                        responseContent.append(e1.getMessage());
                        writeResponse(ctx.channel());
                        ctx.channel().close();
                        return;
                    }
                    responseContent.append('o');
                    try {
                        while (decoder.hasNext()) {
                            InterfaceHttpData data = decoder.next();
                            if (data != null) {
                                try {
                                    writeHttpData(data);
                                } finally {
                                    data.release();
                                }
                            }
                        }
                    } catch (EndOfDataDecoderException e1) {
                        responseContent.append("\r\n\r\nEND OF CONTENT CHUNK BY CHUNK\r\n\r\n");
                    }
    
                    // example of reading only if at the end
                    if (chunk instanceof LastHttpContent) {
                        writeResponse(ctx.channel());
                        readingChunks = false;
                        reset();
                    }
                }
            }
        }
    
        private void reset() {
            request = null;
            // destroy the decoder to release all resources
            decoder.destroy();
            decoder = null;
        }
    
        private void writeHttpData(InterfaceHttpData data) {
            /**
             * HttpDataType有三种类型
             * Attribute, FileUpload, InternalAttribute
             */
            if (data.getHttpDataType() == HttpDataType.Attribute) {
                Attribute attribute = (Attribute) data;
                String value;
                try {
                    value = attribute.getValue();
                } catch (IOException e1) {
                    e1.printStackTrace();
                    responseContent.append("\r\nBODY Attribute: " + attribute.getHttpDataType().name() + ":"
                            + attribute.getName() + " Error while reading value: " + e1.getMessage() + "\r\n");
                    return;
                }
                if (value.length() > 100) {
                    responseContent.append("\r\nBODY Attribute: " + attribute.getHttpDataType().name() + ":"
                            + attribute.getName() + " data too long\r\n");
                } else {
                    responseContent.append("\r\nBODY Attribute: " + attribute.getHttpDataType().name() + ":"
                            + attribute.toString() + "\r\n");
                }
            }
        }
    
        private void writeResponse(Channel channel) {
            // Convert the response content to a ChannelBuffer.
            ByteBuf buf = copiedBuffer(responseContent.toString(), CharsetUtil.UTF_8);
            responseContent.setLength(0);
    
            // Decide whether to close the connection or not.
            boolean close = request.headers().contains(CONNECTION, HttpHeaders.Values.CLOSE, true)
                    || request.getProtocolVersion().equals(HttpVersion.HTTP_1_0)
                    && !request.headers().contains(CONNECTION, HttpHeaders.Values.KEEP_ALIVE, true);
    
            // Build the response object.
            FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf);
            response.headers().set(CONTENT_TYPE, "text/plain; charset=UTF-8");
    
            if (!close) {
                // There's no need to add 'Content-Length' header
                // if this is the last response.
                response.headers().set(CONTENT_LENGTH, buf.readableBytes());
            }
    
            Set<Cookie> cookies;
            String value = request.headers().get(COOKIE);
            if (value == null) {
                cookies = Collections.emptySet();
            } else {
                cookies = CookieDecoder.decode(value);
            }
            if (!cookies.isEmpty()) {
                // Reset the cookies if necessary.
                for (Cookie cookie : cookies) {
                    response.headers().add(SET_COOKIE, ServerCookieEncoder.encode(cookie));
                }
            }
            // Write the response.
            ChannelFuture future = channel.writeAndFlush(response);
            // Close the connection after the write operation is done if necessary.
            if (close) {
                future.addListener(ChannelFutureListener.CLOSE);
            }
        }
    
        private void writeMenu(ChannelHandlerContext ctx) {
            // print several HTML forms
            // Convert the response content to a ChannelBuffer.
            responseContent.setLength(0);
    
            // create Pseudo Menu
            responseContent.append("<html>");
            responseContent.append("<head>");
            responseContent.append("<title>Netty Test Form</title>\r\n");
            responseContent.append("</head>\r\n");
            responseContent.append("<body bgcolor=white><style>td{font-size: 12pt;}</style>");
    
            responseContent.append("<table border=\"0\">");
            responseContent.append("<tr>");
            responseContent.append("<td>");
            responseContent.append("<h1>Netty Test Form</h1>");
            responseContent.append("Choose one FORM");
            responseContent.append("</td>");
            responseContent.append("</tr>");
            responseContent.append("</table>\r\n");
    
            // GET
            responseContent.append("<CENTER>GET FORM<HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
            responseContent.append("<FORM ACTION=\"/from-get\" METHOD=\"GET\">");
            responseContent.append("<input type=hidden name=getform value=\"GET\">");
            responseContent.append("<table border=\"0\">");
            responseContent.append("<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
            responseContent.append("<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
            responseContent.append("<tr><td>Fill with value: <br> <input type=text name=\"secondinfo\" size=20>");
            responseContent
                    .append("<tr><td>Fill with value: <br> <textarea name=\"thirdinfo\" cols=40 rows=10></textarea>");
            responseContent.append("</td></tr>");
            responseContent.append("<tr><td><INPUT TYPE=\"submit\" NAME=\"Send\" VALUE=\"Send\"></INPUT></td>");
            responseContent.append("<td><INPUT TYPE=\"reset\" NAME=\"Clear\" VALUE=\"Clear\" ></INPUT></td></tr>");
            responseContent.append("</table></FORM>\r\n");
            responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
    
            // POST
            responseContent.append("<CENTER>POST FORM<HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
            responseContent.append("<FORM ACTION=\"/from-post\" METHOD=\"POST\">");
            responseContent.append("<input type=hidden name=getform value=\"POST\">");
            responseContent.append("<table border=\"0\">");
            responseContent.append("<tr><td>Fill with value: <br> <input type=text name=\"info\" size=10></td></tr>");
            responseContent.append("<tr><td>Fill with value: <br> <input type=text name=\"secondinfo\" size=20>");
            responseContent
                    .append("<tr><td>Fill with value: <br> <textarea name=\"thirdinfo\" cols=40 rows=10></textarea>");
            responseContent.append("<tr><td>Fill with file (only file name will be transmitted): <br> "
                    + "<input type=file name=\"myfile\">");
            responseContent.append("</td></tr>");
            responseContent.append("<tr><td><INPUT TYPE=\"submit\" NAME=\"Send\" VALUE=\"Send\"></INPUT></td>");
            responseContent.append("<td><INPUT TYPE=\"reset\" NAME=\"Clear\" VALUE=\"Clear\" ></INPUT></td></tr>");
            responseContent.append("</table></FORM>\r\n");
            responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
            responseContent.append("<CENTER><HR WIDTH=\"75%\" NOSHADE color=\"blue\"></CENTER>");
            responseContent.append("</body>");
            responseContent.append("</html>");
    
            ByteBuf buf = copiedBuffer(responseContent.toString(), CharsetUtil.UTF_8);
            // Build the response object.
            FullHttpResponse response = new DefaultFullHttpResponse(
                    HttpVersion.HTTP_1_1, HttpResponseStatus.OK, buf);
    
            response.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8");
            response.headers().set(CONTENT_LENGTH, buf.readableBytes());
    
            // Write the response.
            ctx.channel().writeAndFlush(response);
        }
    
        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            ctx.channel().close();
        }
    
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, HttpObject msg) throws Exception {
            messageReceived(ctx, msg);
        }
    }

4、运行效果

![Center][]

![Center 1][]

5、注意问题

jar包用的是netty-all-4.0.36.Final.jar和netty-example-4.0.0.Alpha1.errai.r1.jar

[Center]: /images/20220724/9575b667075f40a3b8bb39f95f0509c6.png
[Center 1]: /images/20220724/3a6dc4ca3dc6440981baf5a8f42216b3.png