Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF 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 * * http://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 org.apache.flink.runtime.webmonitor; /***************************************************************************** * This code is based on the "HttpUploadServerHandler" from the * Netty project's HTTP server example. * * See http://netty.io and * https://github.com/netty/netty/blob/netty-4.0.31.Final/example/src/main/java/io/netty/example/http/upload/HttpUploadServerHandler.java *****************************************************************************/ import io.netty.buffer.Unpooled; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.HttpContent; import io.netty.handler.codec.http.HttpHeaders; import io.netty.handler.codec.http.HttpMethod; import io.netty.handler.codec.http.HttpObject; import io.netty.handler.codec.http.HttpRequest; 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.codec.http.QueryStringDecoder; import io.netty.handler.codec.http.QueryStringEncoder; import io.netty.handler.codec.http.multipart.DefaultHttpDataFactory; import io.netty.handler.codec.http.multipart.DiskFileUpload; import io.netty.handler.codec.http.multipart.HttpDataFactory; import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder; import io.netty.handler.codec.http.multipart.HttpPostRequestDecoder.EndOfDataDecoderException; import io.netty.handler.codec.http.multipart.InterfaceHttpData; import io.netty.handler.codec.http.multipart.InterfaceHttpData.HttpDataType; import org.apache.flink.util.ExceptionUtils; import java.io.File; import java.io.IOException; import java.nio.charset.Charset; import java.util.UUID; /** * Simple code which handles all HTTP requests from the user, and passes them to the Router * handler directly if they do not involve file upload requests. * If a file is required to be uploaded, it handles the upload, and in the http request to the * next handler, passes the name of the file to the next handler. */ @ChannelHandler.Sharable public class HttpRequestHandler extends SimpleChannelInboundHandler<HttpObject> { private static final Charset ENCODING = Charset.forName("UTF-8"); /** A decoder factory that always stores POST chunks on disk */ private static final HttpDataFactory DATA_FACTORY = new DefaultHttpDataFactory(true); private final File tmpDir; private HttpRequest currentRequest; private HttpPostRequestDecoder currentDecoder; private String currentRequestPath; public HttpRequestHandler(File tmpDir) { this.tmpDir = tmpDir; } @Override public void channelUnregistered(ChannelHandlerContext ctx) throws Exception { if (currentDecoder != null) { currentDecoder.cleanFiles(); } } @Override public void channelRead0(ChannelHandlerContext ctx, HttpObject msg) { try { if (msg instanceof HttpRequest) { currentRequest = (HttpRequest) msg; currentRequestPath = null; if (currentDecoder != null) { currentDecoder.destroy(); currentDecoder = null; } if (currentRequest.getMethod() == HttpMethod.GET || currentRequest.getMethod() == HttpMethod.DELETE) { // directly delegate to the router ctx.fireChannelRead(currentRequest); } else if (currentRequest.getMethod() == HttpMethod.POST) { // POST comes in multiple objects. First the request, then the contents // keep the request and path for the remaining objects of the POST request currentRequestPath = new QueryStringDecoder(currentRequest.getUri()).path(); currentDecoder = new HttpPostRequestDecoder(DATA_FACTORY, currentRequest); } else { throw new IOException("Unsupported HTTP method: " + currentRequest.getMethod().name()); } } else if (currentDecoder != null && msg instanceof HttpContent) { // received new chunk, give it to the current decoder HttpContent chunk = (HttpContent) msg; currentDecoder.offer(chunk); try { while (currentDecoder.hasNext()) { InterfaceHttpData data = currentDecoder.next(); // IF SOMETHING EVER NEEDS POST PARAMETERS, THIS WILL BE THE PLACE TO HANDLE IT // all fields values will be passed with type Attribute. if (data.getHttpDataType() == HttpDataType.FileUpload) { DiskFileUpload file = (DiskFileUpload) data; if (file.isCompleted()) { String name = file.getFilename(); File target = new File(tmpDir, UUID.randomUUID() + "_" + name); file.renameTo(target); QueryStringEncoder encoder = new QueryStringEncoder(currentRequestPath); encoder.addParam("filepath", target.getAbsolutePath()); encoder.addParam("filename", name); currentRequest.setUri(encoder.toString()); } } data.release(); } } catch (EndOfDataDecoderException ignored) { } if (chunk instanceof LastHttpContent) { HttpRequest request = currentRequest; currentRequest = null; currentRequestPath = null; currentDecoder.destroy(); currentDecoder = null; // fire next channel handler ctx.fireChannelRead(request); } } } catch (Throwable t) { currentRequest = null; currentRequestPath = null; if (currentDecoder != null) { currentDecoder.destroy(); currentDecoder = null; } if (ctx.channel().isActive()) { byte[] bytes = ExceptionUtils.stringifyException(t).getBytes(ENCODING); DefaultFullHttpResponse response = new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.INTERNAL_SERVER_ERROR, Unpooled.wrappedBuffer(bytes)); response.headers().set(HttpHeaders.Names.CONTENT_ENCODING, "utf-8"); response.headers().set(HttpHeaders.Names.CONTENT_TYPE, "text/plain"); response.headers().set(HttpHeaders.Names.CONTENT_LENGTH, response.content().readableBytes()); ctx.writeAndFlush(response); } } } }