http://krisjin.github.io/2015/02/14/netty-file-server/

Http介绍

Http(超文本传输协议)协议是建立在TCP传输协议之上的应用成协议,Http由于便捷、快速的方式,适用于分布式超媒体信息系统。Http是目前Web开发的主流协议,基于Http的应用非常广泛,因此掌握HTTP的开发非常重要。由于netty的HTTP协议栈是基于netty的NIO通信框架开发的,所以netty的HTTP协议也是异步非阻塞的。

具体的关于HTTP及Netyy的实现细节在以后的章节在写,先上实例代码:

实例代码

服务端:

public class HttpFileServer {

public void run(final int port, final String url) throws InterruptedException {

EventLoopGroup bossGroup = new NioEventLoopGroup();

EventLoopGroup workerGroup = new NioEventLoopGroup();

try {

ServerBootstrap boot = new ServerBootstrap();

boot.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)

.childHandler(new ChannelInitializer() {

@Override

protected void initChannel(SocketChannel ch) throws Exception {

ch.pipeline().addLast(“http-decoder”, new HttpRequestDecoder());

ch.pipeline().addLast(“http-aggregator”, new HttpObjectAggregator(65536));

ch.pipeline().addLast(“http-encoder”, new HttpResponseEncoder());

ch.pipeline().addLast(“http-chunked”, new ChunkedWriteHandler());

ch.pipeline().addLast(“fileServerHandler”, new HttpFileServerHandler(url));

}

});

ChannelFuture cf =boot.bind(“127.0.0.1”,port).sync();

System.out.println(“Http文件目录服务器启动: http://127.0.0.1:“+port+url);

cf.channel().closeFuture().sync();

} finally {

bossGroup.shutdownGracefully();

workerGroup.shutdownGracefully();

}

}

public static void main(String[] args) throws InterruptedException {

String url=”/src/main/java/";

new HttpFileServer().run(8080, url);

}

}

服务端handler

public class HttpFileServerHandler extends SimpleChannelInboundHandler {

HttpMethod GET = new HttpMethod(“GET”);

private String url;

private final Pattern ALLOWED_FILE_NAME = Pattern.compile("[A-Za-z0-9][-_A-Za-z0-9\.]*");

private final Pattern INSECURE_URI = Pattern.compile(".*[<>&"].*");

public HttpFileServerHandler(String url) {

this.url = url;

}

@Override

protected void messageReceived(ChannelHandlerContext ctx, FullHttpRequest request) throws Exception {

if (!request.getDecoderResult().isSuccess()) {

sendError(ctx, HttpResponseStatus.BAD_REQUEST);

return;

}

if (request.getMethod() != HttpMethod.GET) {

sendError(ctx, HttpResponseStatus.METHOD_NOT_ALLOWED);

return;

}

final String uri = request.getUri();

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("/")) {

sendList(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 e) {

sendError(ctx, HttpResponseStatus.NO_CONTENT);

return;

}

long fileLength = randomAccessFile.length();

HttpResponse response = new DefaultHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);

HttpHeaders.setContentLength(response, fileLength);

setContentTypeHeader(response, file);

if (HttpHeaders.isKeepAlive(request)) {

response.headers().set(HttpHeaders.Names.CONNECTION, HttpHeaders.Values.KEEP_ALIVE);

}

ctx.write(response);

ChannelFuture sendFileFuture;

sendFileFuture = ctx.write(new ChunkedFile(randomAccessFile, 0, fileLength, 8192), ctx.newProgressivePromise());

sendFileFuture.addListener(new ChannelProgressiveFutureListener() {

@Override

public void operationComplete(ChannelProgressiveFuture future) throws Exception {

System.err.println(future.channel() + " transfer complete”);

}

@Override

public void operationProgressed(ChannelProgressiveFuture future, long progress, long total)

throws Exception {

if (total < 0) {

System.err.println(future.channel() + " transfer progress : " + progress);

} else {

System.err.println(future.channel() + " transfer progress : " + progress + " / " + total);

}

}

});

ChannelFuture lastContentFuture = ctx.writeAndFlush(LastHttpContent.EMPTY_LAST_CONTENT);

if (!HttpHeaders.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 void sendError(ChannelHandlerContext ctx, HttpResponseStatus status) {

FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, status, Unpooled.copiedBuffer(

“Failure :” + status + “\r\n”, CharsetUtil.UTF_8));

response.headers().set(HttpHeaders.Names.CONTENT_TYPE, “text/plain; charset=UTF-8”);

ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);

}

public String sanitizeUri(String uri) {

// Decode the path.

try {

uri = URLDecoder.decode(uri, “UTF-8”);

} catch (UnsupportedEncodingException e) {

throw new Error(e);

}

if (uri.isEmpty() || uri.charAt(0) != ‘/') {

return null;

}

// Convert file separators.

uri = uri.replace('/', File.separatorChar);

// Simplistic dumb security check.

// You will have to do something serious in the production environment.

if (uri.contains(File.separator + ‘.') || uri.contains('.’ + File.separator) || uri.charAt(0) == ‘.’

|| uri.charAt(uri.length() - 1) == ‘.’ || INSECURE_URI.matcher(uri).matches()) {

return null;

}

// Convert to absolute path.

return System.getProperty(“user.dir”) + File.separator + uri;

}

public final void sendList(ChannelHandlerContext ctx, File file) {

FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.OK);

response.headers().set(HttpHeaders.Names.CONTENT_TYPE, “text/html; charset=UTF-8”);

StringBuilder sb = new StringBuilder();

String dirPath = file.getPath();

sb.append(“\r\n”);

sb.append(“”);

sb.append(dirPath);

sb.append(“目录: “);

sb.append(“\r\n”);

sb.append("");

sb.append(dirPath).append(“目录: “);

sb.append("\r\n”);

sb.append(“”);

sb.append(“<a href="../">..\r\n”);

for (File f : file.listFiles()) {

if (f.isHidden() || !f.canRead()) {

continue;

}

String name = f.getName();

if (!ALLOWED_FILE_NAME.matcher(name).matches()) {

continue;

}

sb.append(“<a href="");

sb.append(name);

sb.append("">”);

sb.append(name);

sb.append(“\r\n”);

}

sb.append(“\r\n”);

ByteBuf buffer = Unpooled.copiedBuffer(sb, CharsetUtil.UTF_8);

response.content().writeBytes(buffer);

buffer.release();

// Close the connection as soon as the error message is sent.

ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);

}

public void sendRedirect(ChannelHandlerContext ctx, String newUri) {

FullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.FOUND);

response.headers().set(HttpHeaders.Names.LOCATION, newUri);

ctx.writeAndFlush(response).addListener(ChannelFutureListener.CLOSE);

}

private void setContentTypeHeader(HttpResponse response, File file) {

MimetypesFileTypeMap mimeTypeMap = new MimetypesFileTypeMap();

response.headers().set(HttpHeaders.Names.CONTENT_TYPE, mimeTypeMap.getContentType(file.getPath()));

}

}