Java tutorial
/* $Id$ Copyright (C) 2003-2010 Virginia Tech. All rights reserved. SEE LICENSE FOR MORE INFORMATION Author: Middleware Services Email: middleware@vt.edu Version: $Revision$ Updated: $Date$ */ package edu.vt.middleware.ldap.servlets; import java.io.IOException; import java.io.OutputStream; import java.util.Iterator; import javax.naming.directory.SearchResult; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import edu.vt.middleware.ldap.Ldap; import edu.vt.middleware.ldap.LdapConfig; import edu.vt.middleware.ldap.SearchFilter; import edu.vt.middleware.ldap.bean.LdapAttribute; import edu.vt.middleware.ldap.bean.LdapBeanFactory; import edu.vt.middleware.ldap.bean.LdapBeanProvider; import edu.vt.middleware.ldap.bean.LdapEntry; import edu.vt.middleware.ldap.bean.LdapResult; import edu.vt.middleware.ldap.pool.BlockingLdapPool; import edu.vt.middleware.ldap.pool.DefaultLdapFactory; import edu.vt.middleware.ldap.pool.LdapPool; import edu.vt.middleware.ldap.pool.LdapPoolConfig; import edu.vt.middleware.ldap.pool.SharedLdapPool; import edu.vt.middleware.ldap.pool.SoftLimitLdapPool; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * <code>AttributeServlet</code> is a servlet which queries an LDAP and returns * the value of a single attribute. Example: * http://www.server.com/Attribute?query=uid=dfisher&attr=givenName If you need * to pass complex queries, such as (&(cn=daniel*)(surname=fisher)), then the * query must be form encoded. The content returned by the servlet is of type * text/plain, if you want to receive the content as application/octet-stream * that can be specified by passing the content-type=octet param. The following * init params can be set for this servlet: * edu.vt.middleware.ldap.servlets.propertiesFile - to load ldap properties from * * @author Middleware Services * @version $Revision$ $Date$ */ public final class AttributeServlet extends HttpServlet { /** serial version uid. */ private static final long serialVersionUID = -5918353780927139315L; /** Types of available pools. */ private enum PoolType { /** blocking. */ BLOCKING, /** soft limit. */ SOFTLIMIT, /** shared. */ SHARED } /** Log for this class. */ private final Log logger = LogFactory.getLog(AttributeServlet.class); /** Ldap bean factory. */ private LdapBeanFactory beanFactory = LdapBeanProvider.getLdapBeanFactory(); /** Pool to use for searching. */ private LdapPool<Ldap> pool; /** * Initialize this servlet. * * @param config <code>ServletConfig</code> * * @throws ServletException if an error occurs */ public void init(final ServletConfig config) throws ServletException { super.init(config); final String propertiesFile = getInitParameter(ServletConstants.PROPERTIES_FILE); if (this.logger.isDebugEnabled()) { this.logger.debug(ServletConstants.PROPERTIES_FILE + " = " + propertiesFile); } final LdapConfig ldapConfig = LdapConfig .createFromProperties(AttributeServlet.class.getResourceAsStream(propertiesFile)); final String poolPropertiesFile = getInitParameter(ServletConstants.POOL_PROPERTIES_FILE); if (this.logger.isDebugEnabled()) { this.logger.debug(ServletConstants.POOL_PROPERTIES_FILE + " = " + poolPropertiesFile); } final LdapPoolConfig ldapPoolConfig = LdapPoolConfig .createFromProperties(AttributeServlet.class.getResourceAsStream(poolPropertiesFile)); final String poolType = getInitParameter(ServletConstants.POOL_TYPE); if (this.logger.isDebugEnabled()) { this.logger.debug(ServletConstants.POOL_TYPE + " = " + poolType); } if (PoolType.BLOCKING == PoolType.valueOf(poolType)) { this.pool = new BlockingLdapPool(ldapPoolConfig, new DefaultLdapFactory(ldapConfig)); } else if (PoolType.SOFTLIMIT == PoolType.valueOf(poolType)) { this.pool = new SoftLimitLdapPool(ldapPoolConfig, new DefaultLdapFactory(ldapConfig)); } else if (PoolType.SHARED == PoolType.valueOf(poolType)) { this.pool = new SharedLdapPool(ldapPoolConfig, new DefaultLdapFactory(ldapConfig)); } else { throw new ServletException("Unknown pool type: " + poolType); } this.pool.initialize(); final String beanFactoryClass = getInitParameter(ServletConstants.BEAN_FACTORY); if (this.logger.isDebugEnabled()) { this.logger.debug(ServletConstants.BEAN_FACTORY + " = " + beanFactory); } if (beanFactoryClass != null) { try { this.beanFactory = (LdapBeanFactory) Class.forName(beanFactoryClass).newInstance(); } catch (ClassNotFoundException e) { throw new ServletException(e); } catch (InstantiationException e) { throw new ServletException(e); } catch (IllegalAccessException e) { throw new ServletException(e); } } } /** * Handle all requests sent to this servlet. * * @param request <code>HttpServletRequest</code> * @param response <code>HttpServletResponse</code> * * @throws ServletException if an error occurs * @throws IOException if an error occurs */ public void service(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { final String attribute = request.getParameter("attr"); byte[] value = null; final String content = request.getParameter("content-type"); if (content != null && content.equalsIgnoreCase("octet")) { response.setContentType("application/octet-stream"); response.setHeader("Content-Disposition", "attachment; filename=\"" + attribute + ".bin\""); } else { response.setContentType("text/plain"); } try { Ldap ldap = null; try { ldap = this.pool.checkOut(); final Iterator<SearchResult> i = ldap.search(new SearchFilter(request.getParameter("query")), request.getParameterValues("attr")); final LdapResult r = this.beanFactory.newLdapResult(); r.addEntries(i); for (LdapEntry e : r.getEntries()) { final LdapAttribute a = e.getLdapAttributes().getAttribute(attribute); if (a != null && a.getValues().size() > 0) { final Object rawValue = a.getValues().iterator().next(); if (rawValue instanceof String) { final String stringValue = (String) rawValue; value = stringValue.getBytes(); } else { value = (byte[]) rawValue; } } } } finally { this.pool.checkIn(ldap); } if (value != null) { final OutputStream out = response.getOutputStream(); out.write(value); out.flush(); out.close(); } } catch (Exception e) { if (this.logger.isErrorEnabled()) { this.logger.error("Error performing search", e); } throw new ServletException(e.getMessage()); } } /** * Called by the servlet container to indicate to a servlet that the servlet * is being taken out of service. */ public void destroy() { try { this.pool.close(); } finally { super.destroy(); } } }