redirect.java

邮件服务器系统 支持SMTP POP3 是著名的Apache写 有一定的参考价值

/***********************************************************************
 * Copyright (c) 2000-2004 The Apache Software Foundation.             *
 * All rights reserved.                                                *
 * ------------------------------------------------------------------- *
 * Licensed 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.                      *
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package org.apache.james.transport.mailets;

import java.io.PrintWriter;
import java.io.StringWriter;

import java.util.Collection;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Locale;
import java.util.ArrayList;


import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

import org.apache.james.core.MailImpl;

import org.apache.mailet.GenericMailet;
import org.apache.mailet.Mail;
import org.apache.mailet.MailAddress;


/**
 * <P>A mailet providing configurable redirection services.</P>
 * <P>Can produce listserver, forward and notify behaviour, with the original
 * message intact, attached, appended or left out altogether.</P>
 * <P>It differs from {@link Resend} because
 * (i) some defaults are different,
 * notably for the following parameters: <I>&lt;recipients&gt;</I>, <I>&lt;to&gt;</I>,
 * <I>&lt;reversePath&gt;</I> and <I>&lt;inline&gt;</I>;
 * (ii) because it allows the use of the <I>&lt;static&gt;</I> parameter;.<BR>
 * Use <CODE>Resend</CODE> if you need full control, <CODE>Redirect</CODE> if
 * the more automatic behaviour of some parameters is appropriate.</P>
 * <P>This built in functionality is controlled by the configuration as laid out below.
 * In the table please note that the parameters controlling message headers
 * accept the <B>&quot;unaltered&quot;</B> value, whose meaning is to keep the associated
 * header unchanged and, unless stated differently, corresponds to the assumed default
 * if the parameter is missing.</P>
 * <P>The configuration parameters are:</P>
 * <TABLE width="75%" border="1" cellspacing="2" cellpadding="2">
 * <TR valign=top>
 * <TD width="20%">&lt;recipients&gt;</TD>
 * <TD width="80%">
 * A comma delimited list of addresses for recipients of
 * this message; it will use the &quot;to&quot; list if not specified, and &quot;unaltered&quot;
 * if none of the lists is specified.<BR>
 * These addresses will only appear in the To: header if no &quot;to&quot; list is
 * supplied.<BR>
 * Such addresses can contain &quot;full names&quot;, like
 * <I>Mr. John D. Smith &lt;[e-mail]&gt;</I>.<BR>
 * The list can include constants &quot;sender&quot;, &quot;from&quot;, &quot;replyTo&quot;, &quot;postmaster&quot;, &quot;reversePath&quot;, &quot;recipients&quot;, &quot;to&quot;, &quot;null&quot; and &quot;unaltered&quot;;
 * &quot;replyTo&quot; uses the ReplyTo header if available, otherwise the
 * From header if available, otherwise the Sender header if available, otherwise the return-path;
 * &quot;from&quot; is made equivalent to &quot;sender&quot;, and &quot;to&quot; is made equivalent to &quot;recipients&quot;;
 * &quot;null&quot; is ignored.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;to&gt;</TD>
 * <TD width="80%">
 * A comma delimited list of addresses to appear in the To: header;
 * the email will be delivered to any of these addresses if it is also in the recipients
 * list.<BR>
 * The recipients list will be used if this list is not supplied;
 * if none of the lists is specified it will be &quot;unaltered&quot;.<BR>
 * Such addresses can contain &quot;full names&quot;, like
 * <I>Mr. John D. Smith &lt;[e-mail]&gt;</I>.<BR>
 * The list can include constants &quot;sender&quot;, &quot;from&quot;, &quot;replyTo&quot;, &quot;postmaster&quot;, &quot;reversePath&quot;, &quot;recipients&quot;, &quot;to&quot;, &quot;null&quot; and &quot;unaltered&quot;;
 * &quot;from&quot; uses the From header if available, otherwise the Sender header if available,
 * otherwise the return-path;
 * &quot;replyTo&quot; uses the ReplyTo header if available, otherwise the
 * From header if available, otherwise the Sender header if available, otherwise the return-path;
 * &quot;recipients&quot; is made equivalent to &quot;to&quot;;
 * if &quot;null&quot; is specified alone it will remove this header.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;sender&gt;</TD>
 * <TD width="80%">
 * A single email address to appear in the From: and Return-Path: headers and become the sender.<BR>
 * It can include constants &quot;sender&quot;, &quot;postmaster&quot; and &quot;unaltered&quot;;
 * &quot;sender&quot; is equivalent to &quot;unaltered&quot;.<BR>
 * Default: &quot;unaltered&quot;.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;message&gt;</TD>
 * <TD width="80%">
 * A text message to insert into the body of the email.<BR>
 * Default: no message is inserted.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;inline&gt;</TD>
 * <TD width="80%">
 * <P>One of the following items:</P>
 * <UL>
 * <LI>unaltered &nbsp;&nbsp;&nbsp;&nbsp;The original message is the new
 * message, for forwarding/aliasing</LI>
 * <LI>heads&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The
 * headers of the original message are appended to the message</LI>
 * <LI>body&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The
 * body of the original is appended to the new message</LI>
 * <LI>all&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Both
 * headers and body are appended</LI>
 * <LI>none&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Neither
 * body nor headers are appended</LI>
 * </UL>
 * Default: &quot;body&quot;.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;attachment&gt;</TD>
 * <TD width="80%">
 * <P>One of the following items:</P>
 * <UL>
 * <LI>heads&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The headers of the original
 * are attached as text</LI>
 * <LI>body&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The body of the original
 * is attached as text</LI>
 * <LI>all&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Both
 * headers and body are attached as a single text file</LI>
 * <LI>none&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Nothing is attached</LI>
 * <LI>message &nbsp;The original message is attached as type message/rfc822,
 * this means that it can, in many cases, be opened, resent, fw'd, replied
 * to etc by email client software.</LI>
 * </UL>
 * Default: &quot;none&quot;.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;passThrough&gt;</TD>
 * <TD width="80%">
 * true or false, if true the original message continues in the
 * mailet processor after this mailet is finished. False causes the original
 * to be stopped.<BR>
 * Default: false.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;fakeDomainCheck&gt;</TD>
 * <TD width="80%">
 * true or false, if true will check if the sender domain is valid.<BR>
 * Default: true.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;attachError&gt;</TD>
 * <TD width="80%">
 * true or false, if true any error message available to the
 * mailet is appended to the message body (except in the case of inline ==
 * unaltered).<BR>
 * Default: false.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;replyTo&gt;</TD>
 * <TD width="80%">
 * A single email address to appear in the Reply-To: header.<BR>
 * It can include constants &quot;sender&quot;, &quot;postmaster&quot; &quot;null&quot; and &quot;unaltered&quot;;
 * if &quot;null&quot; is specified it will remove this header.<BR>
 * Default: &quot;unaltered&quot;.
 * </TD>
 * </TR>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;reversePath&gt;</TD>
 * <TD width="80%">
 * A single email address to appear in the Return-Path: header.<BR>
 * It can include constants &quot;sender&quot;, &quot;postmaster&quot; and &quot;null&quot;;
 * if &quot;null&quot; is specified then it will set it to <>, meaning &quot;null return path&quot;.<BR>
 * Notice: the &quot;unaltered&quot; value is <I>not allowed</I>.<BR>
 * Default: the value of the <I>&lt;sender&gt;</I> parameter, if set, otherwise remains unaltered.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;subject&gt;</TD>
 * <TD width="80%">
 * An optional string to use as the subject.<BR>
 * Default: keep the original message subject.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;prefix&gt;</TD>
 * <TD width="80%">
 * An optional subject prefix prepended to the original message
 * subject, or to a new subject specified with the <I>&lt;subject&gt;</I> parameter.<BR>
 * For example: <I>[Undeliverable mail]</I>.<BR>
 * Default: &quot;&quot;.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;isReply&gt;</TD>
 * <TD width="80%">
 * true or false, if true the IN_REPLY_TO header will be set to the
 * id of the current message.<BR>
 * Default: false.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;debug&gt;</TD>
 * <TD width="80%">
 * true or false.  If this is true it tells the mailet to write some debugging
 * information to the mailet log.<BR>
 * Default: false.
 * </TD>
 * </TR>
 * <TR valign=top>
 * <TD width="20%">&lt;static&gt;</TD>