How to send base64Url encoded Raw Email message?

Question

I got Gmail RFC 2822 compliant message which contains everything (headers,body,subject etc.). The message is base64url encoded. I am trying to parse this message and send it to Exchange online. So far I have tried Sasa Mime library but this great library doesn't work for me.

string strRaw = System.IO.File.ReadAllText(@"G:\raw.txt");
var mail = Sasa.Net.Mail.Message.Parse(strRaw);

The above code fails with this following exception : Exception Details: System.ArgumentOutOfRangeException: Length cannot be less than zero. Parameter name: length

I request you to tell me which free Mime library I can use to parse Gmail Raw message. Java has a great built-in library called javax.mail.internet (MimeMessage class) which does the job very beautifully. I am using EWS managed Api to work with Exchange online and it's not able to parse Gmail raw message directly.

Edited : removed the encoded message.

best regards,

If the message is base64 encoded, you can just use: msdn.microsoft.com/en-us/library/dhx0d524%28v=vs.110%29.aspx. Aside from that: recommending libraries is off-topic on StackOverflow, since it often leads to discussions about which library is better. Google is less likely to start such discussions: google.com/webhp?q=c%23%20base%2064%20encoding — Frank van Puffelen
Sir, I already using base64url encoder-decoder functions. C# doesn't have built-in support for such functions,however they have function to encode/decode base64 nor base64url. My problem is I am not able to parse gmail raw message to exchange readable format. So that I can send this raw message to exchange programmatically. — User

rene rene · Accepted Answer · 2014-11-29T18:30:33

As you indicated the string is base64url you have to adapt slightly to overcome the difference from orginal base64 as indicated in the wikipedia article.

The following table shows the differences:

standard  | 62 | 63 | pad
-------------------------
base64    | +  | /  | =
base64Url | -  | _  | N/A

Using this knowledge it becomes clear how to convert from a base64Url to the base64 standard that is used by Convert.FromBase64String.

This code shows how that could work:

var base64Url = "UmVjZWl2 ..... rest of your base64url string ... -";

// replace - and _ with their base64 chars
var sb64 = new StringBuilder(base64Url)
              .Replace('-','+')
              .Replace('_', '/');
var bin = Convert.FromBase64String(sb64.ToString());    

Encoding.ASCII.GetString(bin).Dump("valid");

Using above code dumped the following result in my console (part of it):

Received: from removed.googleusercontent.com
named unknown
by gmailapi.google.com
with HTTPREST;
Sat, 29 Nov 2014 04:55:31 -0800
MIME-Version: 1.0
x-no-auto-attachment: 1
Received: by 10.114.186.6; Mon, 17 Nov 2014 07:11:34 -0800 (PST) Date: Sat, 29 Nov 2014 04:55:31 -0800
Message-Id: [removed for privacy]
Subject: Tips for using your new inbox
From: [removed for privacy]
To: "Your Team @365innovate" <[removed for privacy] >
Content-Type: multipart/alternative; boundary=001a11c33c7aee86ee05080f6437

--001a11c33c7aee86ee05080f6437
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

Tips for using your new inbox
[image: Google]

How to send base64Url encoded Raw Email message?

1 Answers