grails - 无法解析 Mime 消息

Question

我有以下 mime 消息:

Return-Path: <some@adress.com>
X-Original-To: some@adress.com
Delivered-To: some@adress.com
Received: from localhost [127.0.0.1]
    by unify-prod with POP3 (fetchmail-6.3.21)
    for <other@localhost> (single-drop); Mon, 03 Aug 2015 12:42:24+0000 (UTC)
Received: from testdomain.com (testdomain.com [192.69.176.183])
    by unify.test.com (Postfix) with ESMTPS id AA3874330B
    for <test@test.com>; Mon,  3 Aug 2015 12:42:23 +0000 (UTC)
 Received: from test.call (test.call [10.3.1.49])
    by test.com (Postfix) with ESMTP id 56EC73BA8C4
    for <test@test.com>; Mon,  3 Aug 2015 12:42:23 +0000 (UTC)
Date: Mon, 3 Aug 2015 12:42:23 +0000 (UTC)
From: test@test.com
To: test@test.com
Message-ID: <385098705.398991.1438605743348.JavaMail.sd@sdapp04>
Subject: Update
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit



|0004625641|
|630805367|
|NA14220388|
|03.08.2015 14:42:23|


||

我想用这段代码解析 grails 中的消息:

InputStream mailFileInputStream = new FileInputStream("/home/peter/test.msg");
    Properties props = new Properties();
    Session session = Session.getDefaultInstance(props, null);
    MimeMessage message = new MimeMessage(session, mailFileInputStream);

    MimeMessageParser parser = new MimeMessageParser(message)
    parser.parse()


    def data = [:]
    data.from = parser.getFrom()
    data.to = parser.getTo()
    data.replyTo = parser.getReplyTo()
    data.html = parser.getHtmlContent()
    data.plain = parser.getPlainContent()
    data.subject = parser.getSubject()
    data.attachments = parser.getAttachmentList()

但是消息没有被正确解析。整个消息都是明文。此消息有什么问题？

最好的问候，彼得

Answer 1

当我尝试解析消息时出现异常:

java.lang.ClassCastException: javax.mail.util.SharedByteArrayInputStream cannot be cast to java.lang.String
    at org.apache.commons.mail.util.MimeMessageParser.parse(MimeMessageParser.java:181)
    at org.apache.commons.mail.util.MimeMessageParser.parse(MimeMessageParser.java:96)
    at org.apache.commons.mail.util.MimeMessageParser$parse.call(Unknown Source)

问题是 MimeMessageParser 试图将 Object 强制转换为 String。你可以在 source code 中看到这个在第 181 行。该对象是 javax.mail.util.SharedByteArrayInputStream 的一个实例，它不会通过强制返回内容。我的示例使用 StringBufferInputStream 作为输入，因此这可能在问题中发挥了作用。

解决方法

为了解决这个问题，我覆盖了 MimeMessage.getContent() 以便它返回纯文本内容。很明显，不要对非纯文本内容执行此操作。这是完整的脚本:

@Grab('org.apache.commons:commons-email:1.4')

import javax.mail.Session
import javax.mail.internet.MimeMessage
import org.apache.commons.mail.util.MimeMessageParser

def input = '''Return-Path: <some@adress.com>
X-Original-To: some@adress.com
Delivered-To: some@adress.com
Received: from localhost [127.0.0.1]
    by unify-prod with POP3 (fetchmail-6.3.21)
    for <other@localhost> (single-drop); Mon, 03 Aug 2015 12:42:24+0000 (UTC)
Received: from testdomain.com (testdomain.com [192.69.176.183])
    by unify.test.com (Postfix) with ESMTPS id AA3874330B
    for <test@test.com>; Mon,  3 Aug 2015 12:42:23 +0000 (UTC)
 Received: from test.call (test.call [10.3.1.49])
    by test.com (Postfix) with ESMTP id 56EC73BA8C4
    for <test@test.com>; Mon,  3 Aug 2015 12:42:23 +0000 (UTC)
Date: Mon, 3 Aug 2015 12:42:23 +0000 (UTC)
From: test@test.com
To: test@test.com
Message-ID: <385098705.398991.1438605743348.JavaMail.sd@sdapp04>
Subject: Update
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit



|0004625641|
|630805367|
|NA14220388|
|03.08.2015 14:42:23|


||'''

// Creates a MimeMessage that makes MimeMessageParser happy.
MimeMessage createMimeMessage(InputStream stream) {
    def getContent = MimeMessage.metaClass.getMetaMethod('getContent')
    def message = new MimeMessage(
        Session.getDefaultInstance(new Properties()), 
        stream)

    /*
     * Override MimeMessage.getContent()
     * to coerce SharedByteArrayInputStream
     * into a String. Groovy does it automatically :)
     */
    message.metaClass.getContent = {
        getContent.invoke(delegate)
    }

    return message
}

def message = createMimeMessage(new StringBufferInputStream(input))
def parser = new MimeMessageParser(message)

parser.parse()

def data = parser.with {
    [
        from: from,
        to: to,
        replyTo: replyTo,
        html: htmlContent,
        plain: plainContent,
        subject: subject,
        attachments: attachmentList,
    ]
}

assert data.from == 'test@test.com'
assert data.to instanceof List
assert data.replyTo == 'test@test.com'
assert data.html == null
assert data.attachments == []
assert data.plain instanceof String

数据 Map 包含以下内容:

[from:test@test.com, to:[test@test.com], replyTo:test@test.com, html:null, plain:

|0004625641|
|630805367|
|NA14220388|
|03.08.2015 14:42:23|


||, subject:Update, attachments:[]]