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 org.apache.jmeter.protocol.http.parser; import java.net.URL; import java.util.Collection; import java.util.Iterator; import java.util.LinkedHashSet; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.commons.lang3.StringUtils; import org.apache.jorphan.logging.LoggingManager; import org.apache.log.Logger; /** * {@link HTMLParser} subclasses can parse HTML content to obtain URLs. * */ public abstract class HTMLParser extends BaseParser { private static final Logger log = LoggingManager.getLoggerForClass(); protected static final String ATT_BACKGROUND = "background";// $NON-NLS-1$ protected static final String ATT_CODE = "code";// $NON-NLS-1$ protected static final String ATT_CODEBASE = "codebase";// $NON-NLS-1$ protected static final String ATT_DATA = "data";// $NON-NLS-1$ protected static final String ATT_HREF = "href";// $NON-NLS-1$ protected static final String ATT_REL = "rel";// $NON-NLS-1$ protected static final String ATT_SRC = "src";// $NON-NLS-1$ protected static final String ATT_STYLE = "style";// $NON-NLS-1$ protected static final String ATT_TYPE = "type";// $NON-NLS-1$ protected static final String ATT_IS_IMAGE = "image";// $NON-NLS-1$ protected static final String TAG_APPLET = "applet";// $NON-NLS-1$ protected static final String TAG_BASE = "base";// $NON-NLS-1$ protected static final String TAG_BGSOUND = "bgsound";// $NON-NLS-1$ protected static final String TAG_BODY = "body";// $NON-NLS-1$ protected static final String TAG_EMBED = "embed";// $NON-NLS-1$ protected static final String TAG_FRAME = "frame";// $NON-NLS-1$ protected static final String TAG_IFRAME = "iframe";// $NON-NLS-1$ protected static final String TAG_IMAGE = "img";// $NON-NLS-1$ protected static final String TAG_INPUT = "input";// $NON-NLS-1$ protected static final String TAG_LINK = "link";// $NON-NLS-1$ protected static final String TAG_OBJECT = "object";// $NON-NLS-1$ protected static final String TAG_SCRIPT = "script";// $NON-NLS-1$ protected static final String STYLESHEET = "stylesheet";// $NON-NLS-1$ protected static final String IE_UA = "MSIE ([0-9]+.[0-9]+)";// $NON-NLS-1$ protected static final Pattern IE_UA_PATTERN = Pattern.compile(IE_UA); private static final float IE_10 = 10.0f; public static final String PARSER_CLASSNAME = "htmlParser.className"; // $NON-NLS-1$ public static final String DEFAULT_PARSER = "org.apache.jmeter.protocol.http.parser.LagartoBasedHtmlParser"; // $NON-NLS-1$ /** * Protected constructor to prevent instantiation except from within * subclasses. */ protected HTMLParser() { } /** * Get the URLs for all the resources that a browser would automatically * download following the download of the HTML content, that is: images, * stylesheets, javascript files, applets, etc... * <p> * URLs should not appear twice in the returned iterator. * <p> * Malformed URLs can be reported to the caller by having the Iterator * return the corresponding RL String. Overall problems parsing the html * should be reported by throwing an HTMLParseException. * @param userAgent * User Agent * * @param html * HTML code * @param baseUrl * Base URL from which the HTML code was obtained * @param encoding Charset * @return an Iterator for the resource URLs * @throws HTMLParseException when parsing the <code>html</code> fails */ @Override public Iterator<URL> getEmbeddedResourceURLs(String userAgent, byte[] html, URL baseUrl, String encoding) throws HTMLParseException { // The Set is used to ignore duplicated binary files. // Using a LinkedHashSet to avoid unnecessary overhead in iterating // the elements in the set later on. As a side-effect, this will keep // them roughly in order, which should be a better model of browser // behaviour. Collection<URLString> col = new LinkedHashSet<>(); return getEmbeddedResourceURLs(userAgent, html, baseUrl, new URLCollection(col), encoding); // An additional note on using HashSets to store URLs: I just // discovered that obtaining the hashCode of a java.net.URL implies // a domain-name resolution process. This means significant delays // can occur, even more so if the domain name is not resolvable. // Whether this can be a problem in practical situations I can't tell, // but // thought I'd keep a note just in case... // BTW, note that using a List and removing duplicates via scan // would not help, since URL.equals requires name resolution too. // The above problem has now been addressed with the URLString and // URLCollection classes. } /** * Get the URLs for all the resources that a browser would automatically * download following the download of the HTML content, that is: images, * stylesheets, javascript files, applets, etc... * <p> * All URLs should be added to the Collection. * <p> * Malformed URLs can be reported to the caller by having the Iterator * return the corresponding RL String. Overall problems parsing the html * should be reported by throwing an HTMLParseException. * <p> * N.B. The Iterator returns URLs, but the Collection will contain objects * of class URLString. * * @param userAgent * User Agent * @param html * HTML code * @param baseUrl * Base URL from which the HTML code was obtained * @param coll * URLCollection * @param encoding Charset * @return an Iterator for the resource URLs * @throws HTMLParseException when parsing the <code>html</code> fails */ public abstract Iterator<URL> getEmbeddedResourceURLs(String userAgent, byte[] html, URL baseUrl, URLCollection coll, String encoding) throws HTMLParseException; /** * Get the URLs for all the resources that a browser would automatically * download following the download of the HTML content, that is: images, * stylesheets, javascript files, applets, etc... * <p> * N.B. The Iterator returns URLs, but the Collection will contain objects * of class URLString. * * @param userAgent * User Agent * @param html * HTML code * @param baseUrl * Base URL from which the HTML code was obtained * @param coll * Collection - will contain URLString objects, not URLs * @param encoding Charset * @return an Iterator for the resource URLs * @throws HTMLParseException when parsing the <code>html</code> fails */ public Iterator<URL> getEmbeddedResourceURLs(String userAgent, byte[] html, URL baseUrl, Collection<URLString> coll, String encoding) throws HTMLParseException { return getEmbeddedResourceURLs(userAgent, html, baseUrl, new URLCollection(coll), encoding); } /** * * @param ieVersion Float IE version * @return true if IE version < IE v10 */ protected final boolean isEnableConditionalComments(Float ieVersion) { // Conditional comment have been dropped in IE10 // http://msdn.microsoft.com/en-us/library/ie/hh801214%28v=vs.85%29.aspx return ieVersion != null && ieVersion.floatValue() < IE_10; } /** * * @param userAgent User Agent * @return version null if not IE or the version after MSIE */ protected Float extractIEVersion(String userAgent) { if (StringUtils.isEmpty(userAgent)) { log.info("userAgent is null"); return null; } Matcher matcher = IE_UA_PATTERN.matcher(userAgent); String ieVersion = null; if (matcher.find()) { if (matcher.groupCount() > 0) { ieVersion = matcher.group(1); } else { ieVersion = matcher.group(); } } if (ieVersion != null) { return Float.valueOf(ieVersion); } else { return null; } } }