Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. 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. For additional information regarding * copyright in this work, please see the NOTICE file in the top level * directory of this distribution. */ package org.apache.roller.weblogger.util; import java.io.IOException; import java.io.StringReader; import java.net.MalformedURLException; import java.net.URL; import java.util.HashMap; import java.util.Map; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.httpclient.HttpClient; import org.apache.commons.httpclient.HttpMethod; import org.apache.commons.httpclient.HttpStatus; import org.apache.commons.httpclient.methods.PostMethod; import org.apache.commons.lang.StringEscapeUtils; import org.apache.commons.lang.StringUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.roller.weblogger.WebloggerException; import org.apache.roller.weblogger.config.WebloggerConfig; import org.apache.roller.weblogger.pojos.WeblogEntry; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; /** * Represents a trackback request. */ public class Trackback { private static final Log log = LogFactory.getLog(Trackback.class); private final WeblogEntry entry; private final String trackbackURL; public Trackback(WeblogEntry tEntry, String tURL) throws TrackbackNotAllowedException { // Make sure trackback to URL is allowed boolean allowTrackback = true; String allowedURLs = WebloggerConfig.getProperty("trackback.allowedURLs"); if (!StringUtils.isEmpty(allowedURLs)) { // in the case that the administrator has enabled trackbacks // for only specific URLs, set it to false by default allowTrackback = false; String[] splitURLs = allowedURLs.split("\\|\\|"); for (int i = 0; i < splitURLs.length; i++) { Matcher m = Pattern.compile(splitURLs[i]).matcher(tURL); if (m.matches()) { allowTrackback = true; break; } } } if (!allowTrackback) { throw new TrackbackNotAllowedException(tURL); } else { // test url try { new URL(tURL); } catch (MalformedURLException ex) { // bad url throw new IllegalArgumentException("bad url: " + tURL); } entry = tEntry; trackbackURL = tURL; } } /** * Sends trackback from entry to remote URL. * See Trackback spec for details: http://www.sixapart.com/pronet/docs/trackback_spec */ public RollerMessages send() throws WebloggerException { RollerMessages messages = new RollerMessages(); log.debug("Sending trackback to url - " + trackbackURL); // Construct data String title = entry.getTitle(); String excerpt = StringUtils.left(Utilities.removeHTML(entry.getDisplayContent()), 255); String url = entry.getPermalink(); String blog_name = entry.getWebsite().getName(); // build trackback post parameters as query string Map params = new HashMap(); params.put("title", URLUtilities.encode(title)); params.put("excerpt", URLUtilities.encode(excerpt)); params.put("url", URLUtilities.encode(url)); params.put("blog_name", URLUtilities.encode(blog_name)); String queryString = URLUtilities.getQueryString(params); log.debug("query string - " + queryString); // prepare http request HttpClient client = new HttpClient(); client.setConnectionTimeout(45 * 1000); HttpMethod method = new PostMethod(trackbackURL); method.setQueryString(queryString); try { // execute trackback int statusCode = client.executeMethod(method); // read response byte[] response = method.getResponseBody(); String responseString = Utilities.escapeHTML(new String(response, "UTF-8")); log.debug("result = " + statusCode + " " + method.getStatusText()); log.debug("response:\n" + responseString); if (statusCode == HttpStatus.SC_OK) { // trackback request succeeded, message will give details try { messages = parseTrackbackResponse(new String(response, "UTF-8"), messages); } catch (Exception e) { // Cannot parse response, indicates failure messages.addError("weblogEdit.trackbackErrorParsing", responseString); } } else if (statusCode == HttpStatus.SC_NOT_FOUND) { // 404, invalid trackback url messages.addError("weblogEdit.trackbackError404"); } else { // some other kind of error with url, like 500, 403, etc // just provide a generic error message and give the http response text messages.addError("weblogEdit.trackbackErrorResponse", new String[] { "" + statusCode, method.getStatusText() }); } } catch (IOException e) { // some kind of transport error sending trackback post log.debug("Error sending trackback", e); messages.addError("weblogEdit.trackbackErrorTransport"); } finally { // release used connection method.releaseConnection(); } return messages; } /** * Parse XML returned from trackback POST, returns error or success message * in RollerMessages object. */ private RollerMessages parseTrackbackResponse(String response, RollerMessages messages) throws JDOMException, IOException { SAXBuilder builder = new SAXBuilder(); Document doc = builder.build(new StringReader(StringEscapeUtils.unescapeHtml(response))); Element root = doc.getRootElement(); if ("response".equals(root.getName())) { int code = -99; try { code = Integer.parseInt(root.getChildText("error")); } catch (NumberFormatException ignoredByDesign) { } String message = root.getChildText("message"); if (code != 0) { messages.addError("weblogEdit.trackbackFailure", Utilities.removeHTML(message)); } else { messages.addMessage("weblogEdit.trackbackSuccess"); } } else { messages.addError("weblogEdit.trackbackErrorParsing", Utilities.removeHTML(response)); } return messages; } }