关于 c#：在 StreamReader 中搜索 base64 编码的内容？

Search for base64 encoded content in StreamReader?

我需要从 IIS 的 SMTP 死信文件夹中解析 NDR 文件。附加到 NDR 的是经过 base64 编码的内容。这就是我需要达到的目标。我希望，使用 StreamReader，这将是一条线，但是当执行 .ReadLine 时，它??们是单独的线。

这里是一个 NDR 示例：

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From: postmaster
To: hidden
Date: Thu, 12 Nov 2009 11:56:14 -0500
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
boundary="9B095B5ADSN=_01CA638BF4740C5500000045spinstitch.com"
X-DSNContext: 7ce717b1 - 1378 - 00000002 - C00402EF
Message-ID:
Subject: Delivery Status Notification (Failure)

This is a MIME-formatted message.
Portions of this message may be unreadable without a MIME-capable mail program.

--9B095B5ADSN=_01CA638BF4740C5500000045spinstitch.com
Content-Type: text/plain; charset=unicode-1-1-utf-7

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.

hidden

--9B095B5ADSN=_01CA638BF4740C5500000045spinstitch.com
Content-Type: message/delivery-status

Reporting-MTA: dns;spinstitch.com
Received-From-MTA: dns;spinstitch
Arrival-Date: Thu, 12 Nov 2009 11:56:11 -0500

Final-Recipient: rfc822;hidden
Action: failed
Status: 5.4.0

--9B095B5ADSN=_01CA638BF4740C5500000045spinstitch.com
Content-Type: message/rfc822

Received: from mail pickup service by spinstitch.com with Microsoft SMTPSVC;
Thu, 12 Nov 2009 11:56:11 -0500
MIME-Version: 1.0
From: hidden
To: hidden
Date: 12 Nov 2009 11:56:11 -0500
Subject: For Sale: 463 Saltaire Dr. Calabash, NC US 28467 $6,800,000
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: base64
Message-ID:
X-OriginalArrivalTime: 12 Nov 2009 16:56:11.0813 (UTC) FILETIME=[09CED550:01CA63B9]

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--9B095B5ADSN=_01CA638BF4740C5500000045spinstitch.com--

此正则表达式匹配您的 base64 字符串并对其进行解码：

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Match m = Regex.Match(
File.ReadAllText(@"c:\\edit1.txt"),
@"X-OriginalArrivalTime:.*?\
\
\
\
([\\s\\S]*)\
\
\
\
");
byte[] data = Convert.FromBase64String(m.Groups[1].Value);

如果您不想使用正则表达式，您可以尝试跳过每一行，直到找到 X-OriginalArrivalTime 标题。从那里，您可以保留每一行，直到找到空行或流结束。