学习链接
HttpObjectDecoder&HttpObjectEncoder源码浅析
HTTP模拟文件列表服务器
FileServer
java
package com.zzhua.file;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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.HttpServerCodec;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
//通过 HTTP 请求 返回访问指定目录的文件列表
public class FileServer {
public static void main(String[] args) {
NioEventLoopGroup bossGroup = new NioEventLoopGroup();
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
//连接指引对象
ServerBootstrap serverBootstrap = new ServerBootstrap();
//链式编程
serverBootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.handler(new LoggingHandler())
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
ChannelPipeline pipeline = socketChannel.pipeline();
//设定编解码器 Netty提供的http 编解码器
pipeline.addLast(new HttpServerCodec());
//数据聚合器 因为是分段传输 处理Http消息的聚合器
pipeline.addLast(new HttpObjectAggregator(512 * 1024));
//支持大数据的文件传输 控制对内存的使用
pipeline.addLast(new ChunkedWriteHandler());
// 添加自定义处理器
pipeline.addLast(new FileServerHandler());
}
});
// 启动服务器
try {
ChannelFuture future = serverBootstrap.bind(9090).sync();
// 阻塞关闭
future.channel().closeFuture().sync();
} catch (Exception e) {
e.printStackTrace();
} finally {
workerGroup.shutdownGracefully();
bossGroup.shutdownGracefully();
}
}
}FileServerHandler
java
package com.zzhua.file;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;
import java.io.File;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.util.regex.Pattern;
/**
* @projectName: gchatsystem
* @package: com.hyc.gchatsystem.file
* @className: FileServerHandler
* @author: 冷环渊 doomwatcher
* @description: TODO
* @date: 2022/4/13 17:36
* @version: 1.0
*/
//文件服务器处理器
public class FileServerHandler extends SimpleChannelInboundHandler<FullHttpRequest> {
private static final Pattern INSECURE_URI = Pattern.compile(".*[<>&\"].*");
//文件名称匹配规则，必须是英文、数字下划线、中划线
private static final Pattern ALLOWED_FILE_NAME = Pattern.compile("[A-Za-z0-9][-_A-Za-z0-9\\.]*");
//文件路徑
private final String url;
public FileServerHandler() {
this.url = "/";
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {
// 如果无法解码,返回400
if (!request.decoderResult().isSuccess()) {
sendError(ctx, HttpResponseStatus.BAD_REQUEST);
return;
}
//只支持GET方法,其他方法返回
if (request.method() != HttpMethod.GET) {
sendError(ctx, HttpResponseStatus.METHOD_NOT_ALLOWED);
return;
}
//获取文件路径
final String uri = request.uri();
// 格式化URL，并且获取文件的磁盘路径
final String path = sanitizeUri(uri);
System.out.println(path);
if (path == null) {
sendError(ctx, HttpResponseStatus.FORBIDDEN);
return;
}
File file = new File(path);
// 如果文件隐藏不可访问或者文件不存在
if (file.isHidden() || !file.exists()) {
sendError(ctx, HttpResponseStatus.NOT_FOUND);
return;
}
//如果是文件目录
if (file.isDirectory()) {
//以/结尾时，就列出文件夹下的所有文件
if (uri.endsWith("/")) {
sendListing(ctx, file);
} else {
//否则进行重定向，打开文件夹，继续深入
sendRedirect(ctx, uri + '/');
}
return;
}
//既不是文件夹，也不是文件
if (!file.isFile()) {
sendError(ctx, HttpResponseStatus.FORBIDDEN);
}
else {
sendFile(ctx, request);
}
}
private void sendFile(ChannelHandlerContext ctx, FullHttpRequest request) {
try {
String uri = request.uri();
File file = new File(System.getProperty("user.dir") + File.separator + uri);
if (!file.exists()) {
throw new FileNotFoundException(file.getPath());
}
DefaultHttpResponse response = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
response.headers().set(HttpHeaderNames.CONTENT_TYPE, "application/octet-stream");
response.headers().set(HttpHeaderNames.CONTENT_DISPOSITION, "attachment; filename=" + URLEncoder.encode(file.getName()));
response.headers().set(HttpHeaderNames.CONTENT_LENGTH, file.length());
ctx.writeAndFlush(response);
HttpChunkedInput httpChunkedInput = new HttpChunkedInput(new ChunkedFile(file));
ctx.writeAndFlush(httpChunkedInput);
} catch (Exception e) {
ctx.fireExceptionCaught(e);
}
}
/**
* 异常处理
*/
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
if (ctx.channel().isActive()) {
sendError(ctx, HttpResponseStatus.INTERNAL_SERVER_ERROR);
}
}
/**
* 格式化uri，返回文件的磁盘路径
* @param uri
* @return
*
*/
private String sanitizeUri(String uri) {
try {
uri = URLDecoder.decode(uri, "UTF-8");
} catch (UnsupportedEncodingException e) {
//用utf-8解码出现错误时，就换种解码方式
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;
}
System.out.println(System.getProperty("user.dir"));
//
return System.getProperty("user.dir") + File.separator + uri;
}
/**
* 展示文件列表
* @param ctx
* @param dir
*
*/
private static void sendListing(ChannelHandlerContext ctx, File dir) {
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);
response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/html; charset=UTF-8");
StringBuilder buf = new StringBuilder();
String dirPath = dir.getPath();
buf.append("<!DOCTYPE html>\r\n");
buf.append("<html><head><title>");
buf.append("使用netty做下载文件服务器");
buf.append("</title></head><body>\r\n");
buf.append("<h3>");
buf.append("当前文件夹位置：");
buf.append(dirPath);
buf.append("</h3>\r\n");
buf.append("<h4>");
buf.append("文件列表");
buf.append("</h4>\r\n");
buf.append("<ul>");
buf.append("<li>上一级链接：<a href=\"../\">..</a></li>\r\n");
for (File f : dir.listFiles()) {
//隐藏文件，不可读文件直接跳过
if (f.isHidden() || !f.canRead()) {
continue;
}
String name = f.getName();
//非英文、数字、下划线、中划线组成的文件，也跳过
if (!ALLOWED_FILE_NAME.matcher(name).matches()) {
continue;
}
buf.append("<li>链接：<a href=\"");
buf.append(name);
buf.append("\">");
buf.append(name);
buf.append("</a></li>\r\n");
}
buf.append("</ul></body></html>\r\n");
ByteBuf buffer = Unpooled.copiedBuffer(buf, CharsetUtil.UTF_8);
response.content().writeBytes(buffer);
buffer.release();
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* 发送重定向
* @param ctx
* @param newUri
*
*/
private static void sendRedirect(ChannelHandlerContext ctx, String newUri) {
FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.FOUND);
//设置访问的url路径为新的文件夹路径
response.headers().set(HttpHeaderNames.LOCATION, newUri);
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
/**
* 显示错误信息
* @param ctx
* @param status
*
*/
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/plain; charset=UTF-8");
ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);
}
}