mailutil.java

jspwiki source code,jspwiki source code

/* 
    JSPWiki - a JSP-based WikiWiki clone.

    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 com.ecyrd.jspwiki.util;

import java.util.Date;
import java.util.Properties;

import javax.mail.*;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;

import org.apache.log4j.Logger;

import com.ecyrd.jspwiki.TextUtil;
import com.ecyrd.jspwiki.WikiEngine;

/**
 * <p>Contains static methods for sending e-mails to recipients using JNDI-supplied
 * <a href="http://java.sun.com/products/javamail/">JavaMail</a>
 * Sessions supplied by a web container (preferred) or configured via
 * <code>jspwiki.properties</code>; both methods are described below.
 * Because most e-mail servers require authentication,
 * for security reasons implementors are <em>strongly</em> encouraged to use
 * container-managed JavaMail Sessions so that passwords are not exposed in
 * <code>jspwiki.properties</code>.</p>
 * <p>To enable e-mail functions within JSPWiki, administrators must do three things:
 * ensure that the required JavaMail JARs are on the runtime classpath, configure
 * JavaMail appropriately, and (recommdended) configure the JNDI JavaMail session factory.</p>
 * <strong>JavaMail runtime JARs</strong>
 * <p>The first step is easy: JSPWiki bundles
 * recent versions of the required JavaMail <code>mail.jar</code> and
 * <code>activation.jar</code> into the JSPWiki WAR file; so, out of the box
 * this is already taken care of. However, when using JNDI-supplied
 * Session factories, these should be moved, <em>not copied</em>, to a classpath location
 * where the JARs can be shared by both the JSPWiki webapp and the container. For example,
 * Tomcat 5 provides the directory <code><var>$CATALINA_HOME</var>/common/lib</code>
 * for storage of shared JARs; move <code>mail.jar</code> and <code>activation.jar</code>
 * there instead of keeping them in <code>/WEB-INF/lib</code>.</p>
 * <strong>JavaMail configuration</strong>
 * <p>Regardless of the method used for supplying JavaMail sessions (JNDI container-managed
 * or via <code>jspwiki.properties</code>, JavaMail needs certain properties
 * set in order to work correctly. Configurable properties are these:</p>
 * <table border="1">
 *   <tr>
 *   <thead>
 *     <th>Property</th>
 *     <th>Default</th>
 *     <th>Definition</th>
 *   <thead>
 *   </tr>
 *   <tr>
 *     <td><code>jspwiki.mail.jndiname</code></td>
 *     <td><code>mail/Session</code></td>
 *     <td>The JNDI name of the JavaMail session factory</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.host</code></td>
 *     <td><code>127.0.0.1</code></td>
 *     <td>The SMTP mail server from which messages will be sent.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.port</code></td>
 *     <td><code>25</code></td>
 *     <td>The port number of the SMTP mail service.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.account</code></td>
 *     <td>(not set)</td>
 *     <td>The user name of the sender. If this value is supplied, the JavaMail
 *     session will attempt to authenticate to the mail server before sending
 *     the message. If not supplied, JavaMail will attempt to send the message
 *     without authenticating (i.e., it will use the server as an open relay).
 *     In real-world scenarios, you should set this value.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.password</code></td>
 *     <td>(not set)</td>
 *     <td>The password of the sender. In real-world scenarios, you
 *     should set this value.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.from</code></td>
 *     <td><code><var>${user.name}</var>@<var>${mail.smtp.host}</var>*</code></td>
 *     <td>The e-mail address of the sender.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.timeout</code></td>
 *     <td><code>5000*</code></td>
 *     <td>Socket I/O timeout value, in milliseconds. The default is 5 seconds.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.connectiontimeout</code></td>
 *     <td><code>5000*</code></td>
 *     <td>Socket connection timeout value, in milliseconds. The default is 5 seconds.</td>
 *   </tr>
 *   <tr>
 *     <td><code>mail.smtp.starttls.enable</code></td>
 *     <td><code>true*</code></td>
 *     <td>If true, enables the use of the STARTTLS command (if
 *     supported by the server) to switch the connection to a
 *     TLS-protected connection before issuing any login commands.
 *     Note that an appropriate trust store must configured so that
 *     the client will trust the server's certificate. By default,
 *     the JRE trust store contains root CAs for most public certificate
 *     authorities.</td>
 *   </tr>
 * </table>
 * <p>*These defaults apply only if the stand-alone Session factory is used
 * (that is, these values are obtained from <code>jspwiki.properties</code>).
 * If using a container-managed JNDI Session factory, the container will
 * likely supply its own default values, and you should probably override
 * them (see the next section).</p>
 * <strong>Container JNDI Session factory configuration</strong>
 * <p>You are strongly encouraged to use a container-managed JNDI factory for
 * JavaMail sessions, rather than configuring JavaMail through <code>jspwiki.properties</code>.
 * To do this, you need to two things: uncomment the <code>&lt;resource-ref&gt;</code> block
 * in <code>/WEB-INF/web.xml</code> that enables container-managed JavaMail, and
 * configure your container's JavaMail resource factory. The <code>web.xml</code>
 * part is easy: just uncomment the section that looks like this:</p>
 * <pre>&lt;resource-ref&gt;
 *   &lt;description>Resource reference to a container-managed JNDI JavaMail factory for sending e-mails.&lt;/description&gt;
 *   &lt;res-ref-name>mail/Session&lt;/res-ref-name&gt;
 *   &lt;res-type>javax.mail.Session&lt;/res-type&gt;
 *   &lt;res-auth>Container&lt;/res-auth&gt;
 * &lt;/resource-ref&gt;</pre>
 * <p>To configure your container's resource factory, follow the directions supplied by
 * your container's documentation. For example, the
 * <a href="http://tomcat.apache.org/tomcat-5.5-doc/jndi-resources-howto.html#JavaMail%20Sessions">Tomcat
 * 5.5 docs</a> state that you need a properly configured <code>&lt;Resource&gt;</code>
 * element inside the JSPWiki webapp's <code>&lt;Context&gt;</code> declaration. Here's an example shows
 * how to do it:</p>
 * <pre>&lt;Context ...&gt;
 * ...
 * &lt;Resource name="mail/Session" auth="Container"
 *           type="javax.mail.Session"
 *           mail.smtp.host="127.0.0.1"/&gt;
 *           mail.smtp.port="25"/&gt;
 *           mail.smtp.account="your-account-name"/&gt;
 *           mail.smtp.password="your-password"/&gt;
 *           mail.from="Snoop Dogg &lt;[e-mail]&gt;"/&gt;
 *           mail.smtp.timeout="5000"/&gt;
 *           mail.smtp.connectiontimeout="5000"/&gt;
 *           mail.smtp.starttls.enable="true"/&gt;
 * ...
 * &lt;/Context&gt;</pre>
 * <p>Note that with Tomcat (and most other application containers) you can also declare the JavaMail
 * JNDI factory as a global resource, shared by all applications, instead of as a local JSPWiki
 * resource as we have done here. For example, the following entry in
 * <code><var>$CATALINA_HOME</var>/conf/server.xml</code> creates a global resource:</p>
 * <pre>&lt;GlobalNamingResources&gt;
 *   &lt;Resource name="mail/Session" auth="Container"
 *             type="javax.mail.Session"
 *             ...
 *             mail.smtp.starttls.enable="true"/&gt;
 * &lt;/GlobalNamingResources&gt;</pre>
 * <p>This approach &#8212; creating a global JNDI resource &#8212; yields somewhat decreased
 * deployment complexity because the JSPWiki webapp no longer needs its own JavaMail resource
 * declaration. However, it is slightly less secure because it means that all other applications
 * can now obtain a JavaMail session if they want to. In many cases, this <em>is</em> what
 * you want.</p>
 * <p>NOTE: Versions of Tomcat 5.5 later than 5.5.17, and up to and including 5.5.23 have a
 * b0rked version of <code><var>$CATALINA_HOME</var>/common/lib/naming-factory.jar</code>
 * that prevents usage of JNDI. To avoid this problem, you should patch your 5.5.23 version
 * of <code>naming-factory.jar</code> with the one from 5.5.17. This is a known issue
 * and the bug report (#40668) is
 * <a href="http://issues.apache.org/bugzilla/show_bug.cgi?id=40668">here</a>.
 *
 * @author Christoph Sauer
 * @author Dan Frankowski
 * @author Andrew Jaquith
 */
public final class MailUtil
{
    private static final String JAVA_COMP_ENV = "java:comp/env";

    private static final String FALSE = "false";

    private static final String TRUE = "true";

    private static boolean c_useJndi = true;

    private static final String PROP_MAIL_AUTH = "mail.smtp.auth";

    protected static final Logger log = Logger.getLogger(MailUtil.class);

    protected static final String DEFAULT_MAIL_JNDI_NAME       = "mail/Session";

    protected static final String DEFAULT_MAIL_HOST            = "localhost";

    protected static final String DEFAULT_MAIL_PORT            = "25";

    protected static final String DEFAULT_MAIL_TIMEOUT         = "5000";

    protected static final String DEFAULT_MAIL_CONN_TIMEOUT    = "5000";

    protected static final String DEFAULT_SENDER               = "jspwiki@localhost";

    protected static final String PROP_MAIL_JNDI_NAME          = "jspwiki.mail.jndiname";

    protected static final String PROP_MAIL_HOST               = "mail.smtp.host";

    protected static final String PROP_MAIL_PORT               = "mail.smtp.port";

    protected static final String PROP_MAIL_ACCOUNT            = "mail.smtp.account";

    protected static final String PROP_MAIL_PASSWORD           = "mail.smtp.password";

    protected static final String PROP_MAIL_TIMEOUT            = "mail.smtp.timeout";

    protected static final String PROP_MAIL_CONNECTION_TIMEOUT = "mail.smtp.connectiontimeout";

    protected static final String PROP_MAIL_TRANSPORT          = "smtp";

    protected static final String PROP_MAIL_SENDER             = "mail.from";

    protected static final String PROP_MAIL_STARTTLS           = "mail.smtp.starttls.enable";

    private static String c_fromAddress = null;
    
    /**
     *  Private constructor prevents instantiation.
     */
    private MailUtil()
    {
    }

    /**
     * <p>Sends an e-mail to a specified receiver using a JavaMail Session supplied
     * by a JNDI mail session factory (preferred) or a locally initialized
     * session based on properties in <code>jspwiki.properties</code>.
     * See the top-level JavaDoc for this class for a description of
     * required properties and their default values.</p>