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Is case important for MIME-Version

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Jeff Orum

unread,
Aug 22, 1996, 3:00:00 AM8/22/96
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In RFC 1521, it says the the version header field in a MIME message is
of the form:

version := "MIME-Version" ":" 1*DIGIT "." 1*DIGIT

other fields have an explicit statemnt that they are case-insensitive,
e.g. the content field:

content := "Content-Type" ":" type "/" subtype *(";"
parameter)
; case-insensitive matching of type and subtype

So is the only acceptable version header MIME-Version? I have gotten
mail with mime-version, Mime-Version, and other combinations. Are these
technically in violation of the RFC?

Thanks,

Jeff Orum
or...@cup.hp.com

Ned Freed

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Aug 23, 1996, 3:00:00 AM8/23/96
to

> In RFC 1521, it says the the version header field in a MIME message is
> of the form:

> version := "MIME-Version" ":" 1*DIGIT "." 1*DIGIT

> other fields have an explicit statemnt that they are case-insensitive,
> e.g. the content field:

> content := "Content-Type" ":" type "/" subtype *(";"
> parameter)
> ; case-insensitive matching of type and subtype

You're comparing apples and oranges here. RFC822 header field tags like
"MIME-Version" and "Content-Type" are one thing; the contents of such fields
are another thing entirely. RFC822 header field tags are always
case-insensitive. This is a general rule that applies to all RFC822 headers; it
is unnecessary to restate it in the MIME documents and hence we never do. (In
other words, you won't find any statement to the effect that the "Content-Type"
field name is case-insensitive either, but it is nevertheless.)

The content of a header field, however, may or may not be case-sensitive. As
such, it is necessary to state what the rules are for each sort of content we
define. This is what is being done in the section you quote -- the type and
subtype values are not case sensitive, but content-type parameter values can
be.

> So is the only acceptable version header MIME-Version? I have gotten
> mail with mime-version, Mime-Version, and other combinations. Are these
> technically in violation of the RFC?

Nope, they are all perfectly legal.

Ned

Kari E. Hurtta

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Aug 24, 1996, 3:00:00 AM8/24/96
to

In article <4vinj6$d...@hpindda.cup.hp.com> or...@cup.hp.com (Jeff Orum) writes:

> In RFC 1521, it says the the version header field in a MIME message is
> of the form:
>
> version := "MIME-Version" ":" 1*DIGIT "." 1*DIGIT
>
> other fields have an explicit statemnt that they are case-insensitive,
> e.g. the content field:
>
> content := "Content-Type" ":" type "/" subtype *(";"
> parameter)
> ; case-insensitive matching of type and subtype
>

> So is the only acceptable version header MIME-Version? I have gotten
> mail with mime-version, Mime-Version, and other combinations. Are these
> technically in violation of the RFC?

Notice that case-insensitivity talks about values of headers. Header
names are always case insensitive because of STD 11 (RFC 822).

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