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 com.cloud.utils.net; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpMethodRetryHandler; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.MultiThreadedHttpConnectionManager; import org.apache.commons.httpclient.NoHttpResponseException; import org.apache.commons.httpclient.UsernamePasswordCredentials; import org.apache.commons.httpclient.auth.AuthScope; import org.apache.log4j.Logger; import java.io.IOException; public final class HTTPUtils { private static final Logger LOGGER = Logger.getLogger(HTTPUtils.class); // The connection manager. private static final MultiThreadedHttpConnectionManager s_httpClientManager = new MultiThreadedHttpConnectionManager(); private HTTPUtils() { } public static HttpClient getHTTPClient() { return new HttpClient(s_httpClientManager); } /** * @return A HttpMethodRetryHandler with given number of retries. */ public static HttpMethodRetryHandler getHttpMethodRetryHandler(final int retryCount) { if (LOGGER.isDebugEnabled()) { LOGGER.debug("Initializing new HttpMethodRetryHandler with retry count " + retryCount); } return new HttpMethodRetryHandler() { @Override public boolean retryMethod(final HttpMethod method, final IOException exception, int executionCount) { if (executionCount >= retryCount) { // Do not retry if over max retry count return false; } if (exception instanceof NoHttpResponseException) { // Retry if the server dropped connection on us return true; } if (!method.isRequestSent()) { // Retry if the request has not been sent fully or // if it's OK to retry methods that have been sent return true; } // otherwise do not retry return false; } }; } /** * @param proxy * @param httpClient */ public static void setProxy(Proxy proxy, HttpClient httpClient) { if (proxy != null && httpClient != null) { if (LOGGER.isDebugEnabled()) { LOGGER.debug("Setting proxy with host " + proxy.getHost() + " and port " + proxy.getPort() + " for host " + httpClient.getHostConfiguration().getHost() + ":" + httpClient.getHostConfiguration().getPort()); } httpClient.getHostConfiguration().setProxy(proxy.getHost(), proxy.getPort()); if (proxy.getUserName() != null && proxy.getPassword() != null) { httpClient.getState().setProxyCredentials(AuthScope.ANY, new UsernamePasswordCredentials(proxy.getUserName(), proxy.getPassword())); } } } /** * @param username * @param password * @param httpClient */ public static void setCredentials(String username, String password, HttpClient httpClient) { if (username != null && password != null && httpClient != null) { if (LOGGER.isDebugEnabled()) { LOGGER.debug("Setting credentials with username " + username + " for host " + httpClient.getHostConfiguration().getHost() + ":" + httpClient.getHostConfiguration().getPort()); } httpClient.getParams().setAuthenticationPreemptive(true); httpClient.getState().setCredentials( new AuthScope(httpClient.getHostConfiguration().getHost(), httpClient.getHostConfiguration().getPort(), AuthScope.ANY_REALM), new UsernamePasswordCredentials(username, password)); } } /** * @param httpClient * @param httpMethod * @return * Returns the HTTP Status Code or -1 if an exception occurred. */ public static int executeMethod(HttpClient httpClient, HttpMethod httpMethod) { // Execute GetMethod try { return httpClient.executeMethod(httpMethod); } catch (IOException e) { LOGGER.warn("Exception while executing HttpMethod " + httpMethod.getName() + " on URL " + httpMethod.getPath()); return -1; } } /** * @param responseCode * @return */ public static boolean verifyResponseCode(int responseCode) { switch (responseCode) { case HttpStatus.SC_OK: case HttpStatus.SC_MOVED_PERMANENTLY: case HttpStatus.SC_MOVED_TEMPORARILY: return true; default: return false; } } }