What is the encoding of an .eml file from IIS's SMTP server?

Question

I need to write a program that read the .eml files from IIS's mail drop box, but I can't find a definitive source that tells me the encoding of the .eml files. Is there a specification somewhere that tells me the encoding of the files, or do I just have to guess/assume one?

I think I found my answer at http://en.wikipedia.org/wiki/MIME: "The basic Internet e-mail transmission protocol, SMTP, supports only 7-bit ASCII characters... " — Mike Comstock, Nov 17 '09 at 17:25
Why don't you add an answer? You won't be able to get rep points but that doesn't matter too much. — ChaosPandion, Nov 17 '09 at 17:51
I hesitate to add it an an answer because I'm not sure if I'm correct :) — Mike Comstock, Nov 19 '09 at 18:08

score 2 · Answer 1 · edited Sep 29 '11 at 16:03

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You need to read the Content-Transfer-Encoding header. This value will tell you how the email is encoded. The most common are 7-Bit (no encoding), Quoted-Printable (where you see a lot of =HEX pairs), and base64 (which is base 64 encoding).

Based upon that header value, you decode the following body part using the specified routine.

edited Sep 29 '11 at 16:03

answered Nov 18 '09 at 14:21

dave wanta

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Thanks Dave. The problem is reading the header itself. Can I assume that the headers are ACII characters? – Mike Comstock Nov 19 '09 at 18:08
Thank you for mentioning the name "Quoted-Printable." I don't think I'd find it in a reasonable amount of time with your answer here. – Achilles Jun 23 '20 at 23:19

score 1 · Answer 2 · answered Oct 29 '12 at 10:20

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Though it's too late to answer but eml file format nothing but a plaintext MIME (rfc822) file format for storing emails.

answered Oct 29 '12 at 10:20

irsis

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score 1 · Accepted Answer · answered Jun 09 '11 at 02:02

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I found my answer at en.wikipedia.org/wiki/MIME: "The basic Internet e-mail transmission protocol, SMTP, supports only 7-bit ASCII characters... "

answered Jun 09 '11 at 02:02

Mike Comstock

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What is the encoding of an .eml file from IIS's SMTP server?

3 Answers3