使用netty自行实现简单的http服务端开发
了解http服务器工作原理:
http客户端和服务器端的交互步骤:
1 client想server发送http请求
2 server端对http请求进行解析
3 server端向client发送http响应
4 client对http响应进行解析
使用netty自行实现http服务端开发:
针对http主要就是接收请求 处理请求 返回响应
Netty的api很简单 创建NioEventLoopGroup,创建ServerBootstrap 不再过多阐述
最主要的就是在初始化channel中的pipeline链上添加一系列操作
1 添加 HttpRequestDecoder() http请求消息解码器
2 添加 HttpObjectAggregator解码器 将多个消息转换为单一的FullHttpRequest或FullHttpResponse对象
3 添加 HttpResponseEncoder() HTTP响应编码器,对HTTP响应进行编码
4 添加 ChunkedWriteHandler的主要作用是支持异步发送大的码流,但不占用过多的内存,防止JAVA内存溢出
http客户端和服务器端的交互步骤:
1 client想server发送http请求
2 server端对http请求进行解析
3 server端向client发送http响应
4 client对http响应进行解析
使用netty自行实现http服务端开发:
针对http主要就是接收请求 处理请求 返回响应
Netty的api很简单 创建NioEventLoopGroup,创建ServerBootstrap 不再过多阐述
最主要的就是在初始化channel中的pipeline链上添加一系列操作
1 添加 HttpRequestDecoder() http请求消息解码器
2 添加 HttpObjectAggregator解码器 将多个消息转换为单一的FullHttpRequest或FullHttpResponse对象
3 添加 HttpResponseEncoder() HTTP响应编码器,对HTTP响应进行编码
4 添加 ChunkedWriteHandler的主要作用是支持异步发送大的码流,但不占用过多的内存,防止JAVA内存溢出
5 添加 HttpFileServerHandler(DEFAULT_URL)) 自定义的通道处理器，其目的是实现服务器的业务逻辑 比如文件服务器。
复写messageReceived 方法体内 主要就是处理get,post请求的处理 等等
具体代码如下(附带注释)
HttpServer
package httpnetty;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.stream.ChunkedWriteHandler;
public class HttpServer {
private static final String DEFAULT_URL = "/src/";
public void run(final int port) throws Exception {
// 内部维护了一组线程，每个线程负责处理多个Channel上的事件，而一个Channel只对应于一个线程，这样可以回避多线程下的数据同步问题
EventLoopGroup bossGroup = new NioEventLoopGroup();
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer() {
@Override
protected void initChannel(SocketChannel ch)
throws Exception {
// HTTP请求消息解码器
ch.pipeline().addLast("http-decoder",
new HttpRequestDecoder());
/*
* HttpObjectAggregator解码器
* 将多个消息转换为单一的FullHttpRequest或FullHttpResponse对象
*/
ch.pipeline().addLast("http-aggregator",
new HttpObjectAggregator(65536));
// HTTP响应编码器,对HTTP响应进行编码
ch.pipeline().addLast("http-encoder",
new HttpResponseEncoder());
// ChunkedWriteHandler的主要作用是支持异步发送大的码流,但不占用过多的内存,防止JAVA内存溢出
ch.pipeline().addLast("http-chunked",
new ChunkedWriteHandler());
//自定义的通道处理器，其目的是实现文件服务器的业务逻辑。
ch.pipeline().addLast("httpServerHandler",
new HttpFileServerHandler(DEFAULT_URL));
}
});
//绑定端口 发起异步连接操作
ChannelFuture future = b.bind("localhost", port).sync();
System.out.println("HTTP Server startup.");
//等待客户端链路关闭
future.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
//优雅退出 释放NIO线程组
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
public static void main(String[] args) throws Exception {
int port = 8080;
new HttpServer().run(port);
}
}
HttpFileServerHandler:
package httpnetty;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.regex.Pattern;
import javax.activation.MimetypesFileTypeMap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelProgressiveFuture;
import io.netty.channel.ChannelProgressiveFutureListener;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.DefaultHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.FullHttpResponse;
import io.netty.handler.codec.http.HttpHeaderNames;
import io.netty.handler.codec.http.HttpHeaderUtil;
import io.netty.handler.codec.http.HttpHeaderValues;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.LastHttpContent;
import io.netty.handler.stream.ChunkedFile;
import io.netty.util.CharsetUtil;
public class HttpFileServerHandler extends SimpleChannelInboundHandler{
private final String url;
public HttpFileServerHandler(String url) {
this.url = url;
}
@Override
protected void messageReceived(ChannelHandlerContext ctx,
FullHttpRequest request) throws Exception {
if(!request.decoderResult().isSuccess())
{
sendError(ctx, HttpResponseStatus.BAD_REQUEST);
return;
}
if(request.method() != HttpMethod.GET)
{
sendError(ctx, HttpResponseStatus.METHOD_NOT_ALLOWED);
return;
}
final String uri = request.uri();
final String path = sanitizeUri(uri);
if(path == null)
{
sendError(ctx, HttpResponseStatus.FORBIDDEN);
return;
}
File file = new File(path);
if(file.isHidden() || !file.exists())
{
sendError(ctx, HttpResponseStatus.NOT_FOUND);
return;
}
if(file.isDirectory())
{
if(uri.endsWith("/"))
{
sendListing(ctx, file);
}else{
sendRedirect(ctx, uri + "/");
}
return;
}
if(!file.isFile())
{
sendError(ctx, HttpResponseStatus.FORBIDDEN);
return;
}
RandomAccessFile randomAccessFile = null;
try{
randomAccessFile = new RandomAccessFile(file, "r");
}catch(FileNotFoundException fnfd){
sendError(ctx, HttpResponseStatus.NOT_FOUND);
return;
}
long fileLength = randomAccessFile.length();
HttpResponse response = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
HttpHeaderUtil.setContentLength(response, fileLength);
// setContentLength(response, fileLength);
setContentTypeHeader(response, file);
if(HttpHeaderUtil.isKeepAlive(request)){
response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.KEEP_ALIVE);
}
ctx.write(response);
ChannelFuture sendFileFuture = null;
sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 0, fileLength, 8192), ctx.newProgressivePromise());
sendFileFuture.addListener(new ChannelProgressiveFutureListener() {
@Override
public void operationComplete(ChannelProgressiveFuture future)
throws Exception {
System.out.println("Transfer complete.");
}
@Override
public void operationProgressed(ChannelProgressiveFuture future,
long progress, long total) throws Exception {
if(total < 0)
System.err.println("Transfer progress: " + progress);
else
System.err.println("Transfer progress: " + progress + "/" + total);
}
});
ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);
if(!HttpHeaderUtil.isKeepAlive(request))
lastContentFuture.addListener(ChannelFutureListener.CLOSE);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
throws Exception {
cause.printStackTrace();
if(ctx.channel().isActive())
sendError(ctx, HttpResponseStatus.INTERNAL_SERVER_ERROR);
}
private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");
private String sanitizeUri(String uri){
try{
uri = URLDecoder.decode(uri, "UTF-8");
}catch(UnsupportedEncodingException e){
try{
uri = URLDecoder.decode(uri, "ISO-8859-1");
}catch(UnsupportedEncodingException e1){
throw new Error();
}
}
if(!uri.startsWith(url))
return null;
if(!uri.startsWith("/"))
return null;
uri = uri.replace('/', File.separatorChar);
if(uri.contains(File.separator + '.') || uri.contains('.' + File.separator) || uri.startsWith(".") || uri.endsWith(".")
|| INSECURE_URI.matcher(uri).matches()){
return null;
}
return System.getProperty("user.dir") + File.separator + uri;
}
private static final Pattern ALLOWED_FILE_NAME = Pattern.compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");
private static void sendListing(ChannelHandlerContext ctx, File dir){
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
// response.headers().set("CONNECT_TYPE", "text/html;charset=UTF-8");
response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=UTF-8");
String dirPath = dir.getPath();
StringBuilder buf = new StringBuilder();
buf.append("\r\n");
buf.append("");
buf.append(dirPath);
buf.append("目录:");
buf.append(" \r\n");
buf.append("");
buf.append(dirPath).append(" 目录：");
buf.append("
\r\n");
buf.append("");
buf.append("- 链接：
\r\n");
for (File f : dir.listFiles()) {
if(f.isHidden() || !f.canRead()) {
continue;
}
String name = f.getName();
if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
continue;
}
buf.append("- 链接：");
buf.append(name);
buf.append("
\r\n");
}
buf.append("
\r\n");
ByteBuf buffer = Unpooled.copiedBuffer(buf,CharsetUtil.UTF_8);
response.content().writeBytes(buffer);
buffer.release();
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void sendRedirect(ChannelHandlerContext ctx, String newUri){
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.FOUND);
// response.headers().set("LOCATIN", newUri);
response.headers().set(HttpHeaderNames.LOCATION, newUri);
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void sendError(ChannelHandlerContext ctx, HttpResponseStatus status){
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, status,
Unpooled.copiedBuffer("Failure: " + status.toString() + "\r\n", CharsetUtil.UTF_8));
response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html;charset=UTF-8");
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
private static void setContentTypeHeader(HttpResponse response, File file){
MimetypesFileTypeMap mimetypesFileTypeMap = new MimetypesFileTypeMap();
response.headers().set(HttpHeaderNames.CONTENT_TYPE, mimetypesFileTypeMap.getContentType(file.getPath()));
}
}