Java tutorial
/* * Copyright 2014 Informatica Corp. * * Licensed 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 com.informatica.surf.sources.http; 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.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import static io.netty.handler.codec.http.HttpHeaders.Names.HOST; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpHeaders.setContentLength; import static io.netty.handler.codec.http.HttpMethod.GET; import static io.netty.handler.codec.http.HttpMethod.POST; import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST; import static io.netty.handler.codec.http.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame; import io.netty.handler.codec.http.websocketx.PingWebSocketFrame; import io.netty.handler.codec.http.websocketx.PongWebSocketFrame; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory; import io.netty.util.CharsetUtil; import java.util.List; import java.util.Queue; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * * @author Informatica Corp */ class HttpServerHandler extends SimpleChannelInboundHandler<Object> { private static final Logger _logger = LoggerFactory.getLogger(HttpServerHandler.class); private final List<String> _ppaths; // POST paths private final List<String> _wpaths; // WebSocket paths; private final Queue<ByteBuf> _messageQueue; private WebSocketServerHandshaker _handshaker; public HttpServerHandler(List<String> ppaths, List<String> wpaths, Queue<ByteBuf> mqueue) { _ppaths = ppaths; _wpaths = wpaths; _messageQueue = mqueue; _logger.info("Initialized HttpHandler."); _logger.info("POST paths:"); for (String s : ppaths) { _logger.info(s); } _logger.info("WebSocket paths:"); for (String s : wpaths) { _logger.info(s); } } @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { if (msg instanceof FullHttpRequest) { handleHttpRequest(ctx, (FullHttpRequest) msg); } else if (msg instanceof WebSocketFrame) { handleWebSocketFrame(ctx, (WebSocketFrame) msg); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { ctx.flush(); } private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) throws Exception { _logger.debug("Got a http request"); // Handle a bad request. if (!req.getDecoderResult().isSuccess()) { _logger.debug("Could not decode request"); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); return; } boolean handled = false; if (req.getMethod() == GET) { _logger.debug("Got a GET request"); String path = req.getUri(); if (_wpaths.contains(path)) { handleWebSocketHandshake(ctx, req); handled = true; } else { _logger.debug("Unknown path {}", path); } } // Handle POST method if (req.getMethod() == POST) { _logger.debug("Got a POST request"); // Check if the URL is present in _ppaths. This means it is a normal POST request String path = req.getUri(); if (_ppaths.contains(path)) { _logger.debug("Path matches POST path list"); handlePost(ctx, req); handled = true; } } if (!handled) { _logger.debug("Could not handle request, returning error"); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); } } private void handlePost(ChannelHandlerContext ctx, FullHttpRequest req) { _messageQueue.add(req.content().retain()); _logger.debug("Added POSTed message to queue"); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, OK)); } private void handleWebSocketHandshake(ChannelHandlerContext ctx, FullHttpRequest req) { String location = "ws://" + req.headers().get(HOST) + req.getUri(); WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(location, null, false); _handshaker = wsFactory.newHandshaker(req); if (_handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel()); } else { _handshaker.handshake(ctx.channel(), req); } } private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { _logger.debug("Handling websocket frame"); // Check for closing frame if (frame instanceof CloseWebSocketFrame) { _handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain()); return; } if (frame instanceof PingWebSocketFrame) { ctx.channel().write(new PongWebSocketFrame(frame.content().retain())); return; } if (!(frame instanceof TextWebSocketFrame)) { throw new UnsupportedOperationException( String.format("%s frame types not supported", frame.getClass().getName())); } String request = ((TextWebSocketFrame) frame).text(); _logger.debug("{} received {}", ctx.channel(), request); _messageQueue.add(frame.content().retain()); //ctx.channel().write(new TextWebSocketFrame(request.toUpperCase())); } private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) { // Generate an error page if response getStatus code is not OK (200). if (res.getStatus().code() != 200) { ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); setContentLength(res, res.content().readableBytes()); } else { setContentLength(res, 0); } // Send the response and close the connection if necessary. ChannelFuture f = ctx.channel().writeAndFlush(res); if (!isKeepAlive(req) || res.getStatus().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { _logger.warn("Exception while handing HTTP request", cause); ctx.close(); } }