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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * */ package org.apache.http.impl.nio.client; import java.io.IOException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.HttpEntityEnclosingRequest; import org.apache.http.HttpException; import org.apache.http.HttpInetConnection; import org.apache.http.HttpRequest; import org.apache.http.HttpResponse; import org.apache.http.HttpStatus; import org.apache.http.nio.ContentDecoder; import org.apache.http.nio.ContentEncoder; import org.apache.http.nio.NHttpClientConnection; import org.apache.http.nio.NHttpClientHandler; import org.apache.http.nio.NHttpConnection; import org.apache.http.nio.client.HttpAsyncExchangeHandler; import org.apache.http.params.CoreProtocolPNames; import org.apache.http.protocol.HttpContext; /** * Fully asynchronous HTTP client side protocol handler that implements the * essential requirements of the HTTP protocol for the server side message * processing as described by RFC 2616. It is capable of executing HTTP requests * with nearly constant memory footprint. Only HTTP message heads are stored in * memory, while content of message bodies is streamed directly from the entity * to the underlying channel (and vice versa) using {@link ConsumingNHttpEntity} * and {@link ProducingNHttpEntity} interfaces. */ class NHttpClientProtocolHandler implements NHttpClientHandler { private final Log log = LogFactory.getLog(getClass()); private static final String HTTP_EXCHNAGE = "http.nio.exchange"; public NHttpClientProtocolHandler() { super(); } private void closeConnection(final NHttpClientConnection conn) { try { conn.close(); } catch (IOException ex) { try { conn.shutdown(); } catch (IOException ignore) { this.log.debug("I/O error terminating connection: " + ex.getMessage(), ex); } } } protected void shutdownConnection(final NHttpClientConnection conn) { try { conn.shutdown(); } catch (IOException ex) { this.log.debug("I/O error terminating connection: " + ex.getMessage(), ex); } } public void connected(final NHttpClientConnection conn, final Object attachment) { HttpExchange httpexchange = new HttpExchange(); HttpContext context = conn.getContext(); if (this.log.isDebugEnabled()) { this.log.debug("Connected " + formatState(conn, httpexchange)); } context.setAttribute(HTTP_EXCHNAGE, httpexchange); requestReady(conn); } public void closed(final NHttpClientConnection conn) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Disconnected " + formatState(conn, httpexchange)); } if (handler != null) { handler.cancel(); } } public void exception(final NHttpClientConnection conn, final HttpException ex) { HttpContext context = conn.getContext(); HttpAsyncExchangeHandler<?> handler = getHandler(context); this.log.error("HTTP protocol exception: " + ex.getMessage(), ex); if (handler != null) { handler.failed(ex); } closeConnection(conn); } public void exception(final NHttpClientConnection conn, final IOException ex) { HttpContext context = conn.getContext(); HttpAsyncExchangeHandler<?> handler = getHandler(context); this.log.error("I/O error: " + ex.getMessage(), ex); if (handler != null) { handler.failed(ex); } shutdownConnection(conn); } public void requestReady(final NHttpClientConnection conn) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Request ready " + formatState(conn, httpexchange)); } if (httpexchange.getRequestState() != MessageState.READY) { return; } if (handler == null || handler.isDone()) { if (this.log.isDebugEnabled()) { this.log.debug("No request submitted " + formatState(conn, httpexchange)); } return; } try { HttpRequest request = handler.generateRequest(); httpexchange.setRequest(request); HttpEntityEnclosingRequest entityReq = null; if (request instanceof HttpEntityEnclosingRequest) { entityReq = (HttpEntityEnclosingRequest) request; } conn.submitRequest(request); if (entityReq != null) { if (entityReq.expectContinue()) { int timeout = conn.getSocketTimeout(); httpexchange.setTimeout(timeout); timeout = request.getParams().getIntParameter(CoreProtocolPNames.WAIT_FOR_CONTINUE, 3000); conn.setSocketTimeout(timeout); httpexchange.setRequestState(MessageState.ACK); } else { httpexchange.setRequestState(MessageState.BODY_STREAM); } } else { httpexchange.setRequestState(MessageState.COMPLETED); } } catch (IOException ex) { if (this.log.isDebugEnabled()) { this.log.debug("I/O error: " + ex.getMessage(), ex); } shutdownConnection(conn); handler.failed(ex); } catch (HttpException ex) { if (this.log.isDebugEnabled()) { this.log.debug("HTTP protocol exception: " + ex.getMessage(), ex); } closeConnection(conn); handler.failed(ex); } } public void inputReady(final NHttpClientConnection conn, final ContentDecoder decoder) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Input ready " + formatState(conn, httpexchange)); } try { handler.consumeContent(decoder, conn); if (decoder.isCompleted()) { processResponse(conn, httpexchange, handler); } } catch (IOException ex) { if (this.log.isDebugEnabled()) { this.log.debug("I/O error: " + ex.getMessage(), ex); } shutdownConnection(conn); handler.failed(ex); } } public void outputReady(final NHttpClientConnection conn, final ContentEncoder encoder) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Output ready " + formatState(conn, httpexchange)); } try { if (httpexchange.getRequestState() == MessageState.ACK) { conn.suspendOutput(); return; } handler.produceContent(encoder, conn); if (encoder.isCompleted()) { httpexchange.setRequestState(MessageState.COMPLETED); } } catch (IOException ex) { if (this.log.isDebugEnabled()) { this.log.debug("I/O error: " + ex.getMessage(), ex); } shutdownConnection(conn); handler.failed(ex); } } public void responseReceived(final NHttpClientConnection conn) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Response received " + formatState(conn, httpexchange)); } try { HttpResponse response = conn.getHttpResponse(); HttpRequest request = httpexchange.getRequest(); int statusCode = response.getStatusLine().getStatusCode(); if (statusCode < HttpStatus.SC_OK) { // 1xx intermediate response if (statusCode == HttpStatus.SC_CONTINUE && httpexchange.getRequestState() == MessageState.ACK) { continueRequest(conn, httpexchange); httpexchange.setRequestState(MessageState.BODY_STREAM); } return; } else { httpexchange.setResponse(response); if (httpexchange.getRequestState() == MessageState.ACK) { cancelRequest(conn, httpexchange); httpexchange.setRequestState(MessageState.COMPLETED); } else if (httpexchange.getRequestState() == MessageState.BODY_STREAM) { // Early response cancelRequest(conn, httpexchange); httpexchange.invalidate(); conn.suspendOutput(); } } handler.responseReceived(response); if (!canResponseHaveBody(request, response)) { processResponse(conn, httpexchange, handler); } } catch (IOException ex) { if (this.log.isDebugEnabled()) { this.log.debug("I/O error: " + ex.getMessage(), ex); } shutdownConnection(conn); handler.failed(ex); } catch (HttpException ex) { if (this.log.isDebugEnabled()) { this.log.debug("HTTP protocol exception: " + ex.getMessage(), ex); } closeConnection(conn); handler.failed(ex); } } public void timeout(final NHttpClientConnection conn) { HttpContext context = conn.getContext(); HttpExchange httpexchange = getHttpExchange(context); HttpAsyncExchangeHandler<?> handler = getHandler(context); if (this.log.isDebugEnabled()) { this.log.debug("Timeout " + formatState(conn, httpexchange)); } try { if (httpexchange.getRequestState() == MessageState.ACK) { continueRequest(conn, httpexchange); httpexchange.setRequestState(MessageState.BODY_STREAM); } else { if (conn.getStatus() == NHttpConnection.ACTIVE) { conn.close(); if (conn.getStatus() == NHttpConnection.CLOSING) { // Give the connection some grace time to // close itself nicely conn.setSocketTimeout(250); } } else { conn.shutdown(); } } } catch (IOException ex) { if (this.log.isDebugEnabled()) { this.log.debug("I/O error: " + ex.getMessage(), ex); } shutdownConnection(conn); handler.failed(ex); } } private HttpExchange getHttpExchange(final HttpContext context) { return (HttpExchange) context.getAttribute(HTTP_EXCHNAGE); } private HttpAsyncExchangeHandler<?> getHandler(final HttpContext context) { return (HttpAsyncExchangeHandler<?>) context .getAttribute(DefaultAsyncRequestDirector.HTTP_EXCHANGE_HANDLER); } private void continueRequest(final NHttpClientConnection conn, final HttpExchange httpexchange) { int timeout = httpexchange.getTimeout(); conn.setSocketTimeout(timeout); conn.requestOutput(); } private void cancelRequest(final NHttpClientConnection conn, final HttpExchange httpexchange) throws IOException { int timeout = httpexchange.getTimeout(); conn.setSocketTimeout(timeout); conn.resetOutput(); httpexchange.resetOutput(); } private void processResponse(final NHttpClientConnection conn, final HttpExchange httpexchange, final HttpAsyncExchangeHandler<?> handler) throws IOException { if (!httpexchange.isValid()) { conn.close(); } HttpRequest request = httpexchange.getRequest(); HttpResponse response = httpexchange.getResponse(); String method = request.getRequestLine().getMethod(); int status = response.getStatusLine().getStatusCode(); if (method.equalsIgnoreCase("CONNECT") && status == HttpStatus.SC_OK) { this.log.debug("CONNECT method succeeded"); conn.resetInput(); } else { if (!handler.keepAlive(response)) { conn.close(); } } if (this.log.isDebugEnabled()) { this.log.debug("Response processed " + formatState(conn, httpexchange)); } handler.responseCompleted(); httpexchange.reset(); } private boolean canResponseHaveBody(final HttpRequest request, final HttpResponse response) { String method = request.getRequestLine().getMethod(); int status = response.getStatusLine().getStatusCode(); if (method.equalsIgnoreCase("HEAD")) { return false; } if (method.equalsIgnoreCase("CONNECT") && status == HttpStatus.SC_OK) { return false; } return status >= HttpStatus.SC_OK && status != HttpStatus.SC_NO_CONTENT && status != HttpStatus.SC_NOT_MODIFIED && status != HttpStatus.SC_RESET_CONTENT; } private String formatState(final NHttpConnection conn, final HttpExchange httpexchange) { StringBuilder buf = new StringBuilder(); buf.append("["); if (conn.isOpen() && (conn instanceof HttpInetConnection)) { HttpInetConnection inetconn = (HttpInetConnection) conn; buf.append(inetconn.getRemoteAddress()); buf.append(":"); buf.append(inetconn.getRemotePort()); } buf.append("("); buf.append(conn.isOpen() ? "open" : "closed"); buf.append("),request="); buf.append(httpexchange.getRequestState()); if (httpexchange.getRequest() != null) { buf.append("("); buf.append(httpexchange.getRequest().getRequestLine()); buf.append(")"); } buf.append(",response="); buf.append(httpexchange.getResponseState()); if (httpexchange.getResponse() != null) { buf.append("("); buf.append(httpexchange.getResponse().getStatusLine()); buf.append(")"); } buf.append(",valid="); buf.append(httpexchange.isValid()); buf.append("]"); return buf.toString(); } }