Java tutorial
/* * Copyright (C) 2012 The Android Open Source Project * * 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 org.eclipse.andmore.android.common.utilities; import java.io.IOException; import java.io.InputStream; import java.net.Authenticator; import java.util.HashMap; import java.util.Map; import org.apache.commons.httpclient.Credentials; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.UsernamePasswordCredentials; import org.apache.commons.httpclient.auth.AuthScope; import org.apache.commons.httpclient.auth.AuthState; import org.apache.commons.httpclient.methods.GetMethod; import org.apache.commons.httpclient.params.HttpClientParams; import org.apache.commons.httpclient.params.HttpMethodParams; import org.eclipse.andmore.android.common.log.AndmoreLogger; import org.eclipse.andmore.android.common.utilities.i18n.UtilitiesNLS; import org.eclipse.andmore.android.common.utilities.ui.LoginPasswordDialogCreator; import org.eclipse.core.internal.net.ProxyManager; import org.eclipse.core.net.proxy.IProxyData; import org.eclipse.core.net.proxy.IProxyService; import org.eclipse.core.runtime.IProgressMonitor; import org.eclipse.core.runtime.SubMonitor; import org.eclipse.ui.internal.net.auth.NetAuthenticator; /** * Class for opening an input stream with the given URL. */ @SuppressWarnings("restriction") public class HttpUtils { /** * 1 second if the unit is milliseconds. */ private static final int ONE_SECOND = 1000; // map of credentials authentication so the user is not repeatedly asked for // them private static final Map<String, Credentials> authenticationRealmCache = new HashMap<String, Credentials>(); private GetMethod getMethod; /** * Retrieves an open InputStream with the contents of the file pointed by * the given url. * * @param url * The address from where to retrieve the InputStream * @param monitor * The monitor to progress while accessing the file * * @return The open InputStream object, or <code>null</code> if no file was * found * * @throws IOException * if some error occurs with the network communication */ public InputStream getInputStreamForUrl(String url, IProgressMonitor monitor) throws IOException { return getInputStreamForUrl(url, monitor, true); } private InputStream getInputStreamForUrl(String url, IProgressMonitor monitor, boolean returnStream) throws IOException { SubMonitor subMonitor = SubMonitor.convert(monitor); subMonitor.beginTask(UtilitiesNLS.HttpUtils_MonitorTask_PreparingConnection, 300); AndmoreLogger.debug(HttpUtils.class, "Verifying proxy usage for opening http connection"); //$NON-NLS-1$ // Try to retrieve proxy configuration to use if necessary IProxyService proxyService = ProxyManager.getProxyManager(); IProxyData proxyData = null; if (proxyService.isProxiesEnabled() || proxyService.isSystemProxiesEnabled()) { Authenticator.setDefault(new NetAuthenticator()); if (url.startsWith("https")) { proxyData = proxyService.getProxyData(IProxyData.HTTPS_PROXY_TYPE); AndmoreLogger.debug(HttpUtils.class, "Using https proxy"); //$NON-NLS-1$ } else if (url.startsWith("http")) { proxyData = proxyService.getProxyData(IProxyData.HTTP_PROXY_TYPE); AndmoreLogger.debug(HttpUtils.class, "Using http proxy"); //$NON-NLS-1$ } else { AndmoreLogger.debug(HttpUtils.class, "Not using any proxy"); //$NON-NLS-1$ } } // Creates the http client and the method to be executed HttpClient client = null; client = new HttpClient(); // If there is proxy data, work with it if (proxyData != null) { if (proxyData.getHost() != null) { // Sets proxy host and port, if any client.getHostConfiguration().setProxy(proxyData.getHost(), proxyData.getPort()); } if ((proxyData.getUserId() != null) && (proxyData.getUserId().trim().length() > 0)) { // Sets proxy user and password, if any Credentials cred = new UsernamePasswordCredentials(proxyData.getUserId(), proxyData.getPassword() == null ? "" : proxyData.getPassword()); //$NON-NLS-1$ client.getState().setProxyCredentials(AuthScope.ANY, cred); } } InputStream streamForUrl = null; getMethod = new GetMethod(url); getMethod.setFollowRedirects(true); // set a 30 seconds timeout HttpMethodParams params = getMethod.getParams(); params.setSoTimeout(15 * ONE_SECOND); getMethod.setParams(params); boolean trying = true; Credentials credentials = null; subMonitor.worked(100); subMonitor.setTaskName(UtilitiesNLS.HttpUtils_MonitorTask_ContactingSite); do { AndmoreLogger.info(HttpUtils.class, "Attempting to make a connection"); //$NON-NLS-1$ // retry to connect to the site once, also set the timeout for 5 // seconds HttpClientParams clientParams = client.getParams(); clientParams.setIntParameter(HttpClientParams.MAX_REDIRECTS, 1); clientParams.setSoTimeout(5 * ONE_SECOND); client.setParams(clientParams); client.executeMethod(getMethod); if (subMonitor.isCanceled()) { break; } else { AuthState authorizationState = getMethod.getHostAuthState(); String authenticationRealm = authorizationState.getRealm(); if (getMethod.getStatusCode() == HttpStatus.SC_UNAUTHORIZED) { AndmoreLogger.debug(HttpUtils.class, "Client requested authentication; retrieving credentials"); //$NON-NLS-1$ credentials = authenticationRealmCache.get(authenticationRealm); if (credentials == null) { AndmoreLogger.debug(HttpUtils.class, "Credentials not found; prompting user for login/password"); //$NON-NLS-1$ subMonitor.setTaskName(UtilitiesNLS.HttpUtils_MonitorTask_WaitingAuthentication); LoginPasswordDialogCreator dialogCreator = new LoginPasswordDialogCreator(url); if (dialogCreator.openLoginPasswordDialog() == LoginPasswordDialogCreator.OK) { credentials = new UsernamePasswordCredentials(dialogCreator.getTypedLogin(), dialogCreator.getTypedPassword()); } else { // cancel pressed; stop trying trying = false; // set the monitor canceled to be able to stop // process subMonitor.setCanceled(true); } } if (credentials != null) { AuthScope scope = new AuthScope(null, -1, authenticationRealm); client.getState().setCredentials(scope, credentials); } subMonitor.worked(100); } else if (getMethod.getStatusCode() == HttpStatus.SC_OK) { AndmoreLogger.debug(HttpUtils.class, "Http connection suceeded"); //$NON-NLS-1$ subMonitor.setTaskName(UtilitiesNLS.HttpUtils_MonitorTask_RetrievingSiteContent); if ((authenticationRealm != null) && (credentials != null)) { authenticationRealmCache.put(authenticationRealm, credentials); } else { // no authentication was necessary, just work the // monitor subMonitor.worked(100); } AndmoreLogger.info(HttpUtils.class, "Retrieving site content"); //$NON-NLS-1$ // if the stream should not be returned (ex: only testing // the connection is // possible), then null will be returned if (returnStream) { streamForUrl = getMethod.getResponseBodyAsStream(); } // succeeded; stop trying trying = false; subMonitor.worked(100); } else { // unhandled return status code trying = false; subMonitor.worked(200); } } } while (trying); subMonitor.done(); return streamForUrl; } /** * Check if a connection with the given URL can be established. * * @param url * The URL to test the connection. * * @return <code>true</code> if the connection can be established; * <code>false</code> otherwise */ public boolean isConnectionOk(String url) { try { getInputStreamForUrl(url, null, false); // no need to release connection since the stream has not been // retrieved // if the code above does not throw any exception, the connection is // fine return true; } catch (Exception e) { return false; } } /** * Release the http connection after users finished reading the InputStream * provided by the {@link #getInputStreamForUrl(String, IProgressMonitor)} * method. */ public void releaseConnection() { if (getMethod != null) { Thread t = new Thread() { /* * (non-Javadoc) * * @see java.lang.Thread#run() */ @Override public void run() { getMethod.releaseConnection(); } }; t.start(); } } }