如何在电子邮件中解码主题？

Question

我已发送主题行的邮件为

[BILLING #PHY-945-49853]: [Ticket #12622] Payment Method

但是在消息来源中,线条如下所示

Subject: =?UTF-8?B?W1NBTEVTICNCQk4tOTM1LTM3OTE3XTogW1RpY2tldCAjMTI2MjJdIFBheW1lbnQ=?=
=?UTF-8?B?IE1ldGhvZA==?=

它在Base64中编码.如何使用php将其解码回英文原文？我尝试过使用php base64_decode($subject)但它没有将其解码为原始主题([BILLING#PHY-945-49853]:[Ticket#12622]付款方式)

我还附上了一封示例电子邮件:

Return-Path: .........
X-Original-To: ..........
Delivered-To: ........
Received: ......
X-DKIM: ........
Received:....
To: ....
Subject: =?UTF-8?B?W1NBTEVTICNCQk4tOTM1LTM3OTE3XTogW1RpY2tldCAjMTI2MjJdIFBheW1lbnQ=?=
=?UTF-8?B?IE1ldGhvZA==?=
From: =?UTF-8?B?U0FWVllFSE9TVElORyBTQUxFUw==?=
X-Priority: ..
X-MSMail-Priority: normal
X-MimeOLE: Produced By Kayako Fusion v4.01.204
X-Mailer: Kayako Fusion v4.01.204
Reply-To: .......
Date: .....
Content-Type: multipart/alternative;
boundary="=_1.64496c432f57488924404b338155a2d7"
MIME-Version: 1.0
Message-Id: ....

这是MIME格式的消息.如果您看到此消息,则您的邮件阅读器不支持此格式.

--=_1.64496c432f57488924404b338155a2d7
Content-Type: text/plain;
charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline


------------------------------------------------------
Support Center:
Content-Type: text/html;
charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

Answer 1

你可能正在寻找iconv_mime_decode.

从链接:

string iconv_mime_decode ( string $encoded_header [, int $mode = 0 [, string $charset = 
ini_get("iconv.internal_encoding") ]] )

解码MIME标头字段.

你的例子:

echo iconv_mime_decode($string);

产量:

Subject: [SALES #BBN-935-37917]: [Ticket #12622] Payment