| // |
| // ======================================================================== |
| // Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd. |
| // ------------------------------------------------------------------------ |
| // All rights reserved. This program and the accompanying materials |
| // are made available under the terms of the Eclipse Public License v1.0 |
| // and Apache License v2.0 which accompanies this distribution. |
| // |
| // The Eclipse Public License is available at |
| // http://www.eclipse.org/legal/epl-v10.html |
| // |
| // The Apache License v2.0 is available at |
| // http://www.opensource.org/licenses/apache2.0.php |
| // |
| // You may elect to redistribute this code under either of these licenses. |
| // ======================================================================== |
| // |
| |
| package org.eclipse.jetty.servlets; |
| |
| import java.io.IOException; |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.regex.Matcher; |
| import java.util.regex.Pattern; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterChain; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| import javax.servlet.http.HttpServletRequest; |
| |
| /* ------------------------------------------------------------ */ |
| /** User Agent Filter. |
| * <p> |
| * This filter allows efficient matching of user agent strings for |
| * downstream or extended filters to use for browser specific logic. |
| * </p> |
| * <p> |
| * The filter is configured with the following init parameters: |
| * <dl> |
| * <dt>attribute</dt><dd>If set, then the request attribute of this name is set with the matched user agent string</dd> |
| * <dt>cacheSize</dt><dd>The size of the user-agent cache, used to avoid reparsing of user agent strings. The entire cache is flushed |
| * when this size is reached</dd> |
| * <dt>userAgent</dt><dd>A regex {@link Pattern} to extract the essential elements of the user agent. |
| * The concatenation of matched pattern groups is used as the user agent name</dd> |
| * <dl> |
| * An example value for pattern is <code>(?:Mozilla[^\(]*\(compatible;\s*+([^;]*);.*)|(?:.*?([^\s]+/[^\s]+).*)</code>. These two |
| * pattern match the common compatibility user-agent strings and extract the real user agent, failing that, the first |
| * element of the agent string is returned. |
| * |
| * |
| */ |
| public class UserAgentFilter implements Filter |
| { |
| private static final String __defaultPattern = "(?:Mozilla[^\\(]*\\(compatible;\\s*+([^;]*);.*)|(?:.*?([^\\s]+/[^\\s]+).*)"; |
| private Pattern _pattern = Pattern.compile(__defaultPattern); |
| private Map<String, String> _agentCache = new ConcurrentHashMap<String, String>(); |
| private int _agentCacheSize=1024; |
| private String _attribute; |
| |
| /* ------------------------------------------------------------ */ |
| /* (non-Javadoc) |
| * @see javax.servlet.Filter#destroy() |
| */ |
| public void destroy() |
| { |
| } |
| |
| /* ------------------------------------------------------------ */ |
| /* (non-Javadoc) |
| * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain) |
| */ |
| public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException |
| { |
| if (_attribute!=null && _pattern!=null) |
| { |
| String ua=getUserAgent(request); |
| request.setAttribute(_attribute,ua); |
| } |
| chain.doFilter(request,response); |
| } |
| |
| /* ------------------------------------------------------------ */ |
| /* (non-Javadoc) |
| * @see javax.servlet.Filter#init(javax.servlet.FilterConfig) |
| */ |
| public void init(FilterConfig filterConfig) throws ServletException |
| { |
| _attribute=filterConfig.getInitParameter("attribute"); |
| |
| String p=filterConfig.getInitParameter("userAgent"); |
| if (p!=null) |
| _pattern=Pattern.compile(p); |
| |
| String size=filterConfig.getInitParameter("cacheSize"); |
| if (size!=null) |
| _agentCacheSize=Integer.parseInt(size); |
| } |
| |
| /* ------------------------------------------------------------ */ |
| public String getUserAgent(ServletRequest request) |
| { |
| String ua=((HttpServletRequest)request).getHeader("User-Agent"); |
| return getUserAgent(ua); |
| } |
| |
| /* ------------------------------------------------------------ */ |
| /** Get UserAgent. |
| * The configured agent patterns are used to match against the passed user agent string. |
| * If any patterns match, the concatenation of pattern groups is returned as the user agent |
| * string. Match results are cached. |
| * @param ua A user agent string |
| * @return The matched pattern groups or the original user agent string |
| */ |
| public String getUserAgent(String ua) |
| { |
| if (ua == null) |
| return null; |
| |
| String tag = _agentCache.get(ua); |
| |
| if (tag == null) |
| { |
| if (_pattern != null) |
| { |
| Matcher matcher = _pattern.matcher(ua); |
| if (matcher.matches()) |
| { |
| if (matcher.groupCount() > 0) |
| { |
| for (int g = 1; g <= matcher.groupCount(); g++) |
| { |
| String group = matcher.group(g); |
| if (group != null) |
| tag = tag == null ? group : tag + group; |
| } |
| } |
| else |
| { |
| tag = matcher.group(); |
| } |
| } |
| } |
| |
| if (tag == null) |
| tag = ua; |
| |
| if (_agentCache.size() >= _agentCacheSize) |
| _agentCache.clear(); |
| _agentCache.put(ua, tag); |
| } |
| |
| return tag; |
| } |
| } |