Format of .EML files

[Rav]

When I right-click on an e-mail message in Thunderbird (version 10.0.2)
and select Save As, it saves the message in a file with an .EML
extension. When I double-click on that file, it opens it in Thunderbird
and everything is as I expect it to look.

I Googled about files with .EML extensions, and found one place where it
said "primarily associated with 'Outlook Express' by Microsoft
Corporation," and ".EML files are used by other E-mail clients as well."

When I looked at the content of the file (in an editor), it appeared to
be a combination of recognizable text as well as a bunch of other stuff
(HTML? Not sure). Is this a "standard" file format for storing
individual e-mail messages? Will such a file always be guaranteed to be
able to be opened and displayed properly by future versions of
Thunderbird? Can the .EML files saved by Thunderbird be opened and
displayed properly by other e-mail clients (I don't have any to try)?
Thanks.

[Ann Watson]

See this link (although it's sort of an ad for a utility it
explains a lot about the .eml format):
http://www.coolutils.com/Formats/EML

Ann

[Rav]

Thank you, Ann. The explanation on that web page is quite helpful.

[Ron K.]

Rav on 3/12/2012 3:17 PM, keyboarded a reply:

Support for the *.eml format was deliberately added to TB early in the
life of the project. A strength of the file is they can contain a mix of
text/html and text/plain which are both ASCII text based, thus readable
with a text editor if an e-mail client is not available.

--
Ron K.
Who is General Failure, and why is he searching my HDD?
Kernel Restore reported Major Error used BSOD to msg the enemy!

[Arivald]

W dniu 2012-03-12 19:33, Rav pisze:

Basically it is mail, as it was received. Or, in case of saving draft,
as it should be send.

Mails are received as stream of bytes, with headers on top, empty line
(begin of body marker) and body. It was enough in early days of mail,
for plain text.
Later, to allow more complex mails, MIME standard emerge. It allow to
split body into several parts, some for real text body, some for inline
images, some for attachments.

So, text what You see in EML file depends much on particular email
program, its settings and mail content. Adding simple attachment adds
complexity.
Still, it is well defined format, and all programs that can use mail
from network is also capable of reading EML file.

--
Arivald

[Man-wai Chang]

> I Googled about files with .EML extensions, and found one place where it
> said "primarily associated with 'Outlook Express' by Microsoft
> Corporation," and ".EML files are used by other E-mail clients as well."

It's just a plain text file that follow RFC 822 if I remember correctly...

Standard for ARPA Internet Text Messages
http://www.w3.org/Protocols/rfc822/

MIME Attachment follows different standards:
http://www.livinginternet.com/e/ea_att_mime.htm


--
@~@ You have the right to remain silent.
/ v \ Simplicity is Beauty!
/( _ )\ May the Force and farces be with you!
^ ^ (x86_64 Ubuntu 9.10) Linux 2.6.39.3
不借貸! 不詐騙! 不援交! 不打交! 不打劫! 不自殺! 請考慮綜援 (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

[Michael A. Puls II]

On Tue, 13 Mar 2012 08:55:40 -0400, Man-wai Chang
<toylet...@gmail.com> wrote:

>> I Googled about files with .EML extensions, and found one place where it
>> said "primarily associated with 'Outlook Express' by Microsoft
>> Corporation," and ".EML files are used by other E-mail clients as well."
>
> It's just a plain text file that follow RFC 822 if I remember
> correctly...

Yeh, <http://tools.ietf.org/html/rfc822> ->
<http://tools.ietf.org/html/rfc2822> ->
<http://tools.ietf.org/html/rfc5322>.

Also, most clients make use of the standard mbox format
<http://en.wikipedia.org/wiki/Mbox> (for exporting, importing and storage
of messages). Mbox files (files with an .mbs extension when used with
Opera's built-in mail client and no extension when used with most other
clients) are basically eml files that hold more than one message where the
messages are separated by a blank line where each message starts with a
"From " line. (There's also escape of lines in the body that start with
"From " in some bases.

Thunderbird stores a folder's messages in an mbox file. It can import and
export them with <http://nic-nac-project.de/~kaosmos/mboximport-en.html>.
By default though, Thunderbird only opens and saves eml files instead
though. But, if you need to import those eml files into another client and
don't what to use that extension, you can edit each one and add a "From "
line to make it an mbox file.

Both Mbox files and eml files are popular. But, besides Thunderbird, eml
files seem to be more associated with MS clients.

EML though (message/rfc822) is usually what you get when you forward a
message as an attachment. But, in Opera's built-in mail client for
example, it's common to attachm mbox files with an mbs extension that get
attached with the application/mime mime type instead. The problem with
that though is that MS clients don't understand that. So, because of MS
clients, it's sometimes good to support eml also.

--
Michael