media type
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... header field, generalized from RFC 1049hist,
which can be used to specify the media type and subtype
of data in the body of a message and to fully specify
the native representation (canonical form ...
... All numeric and octet values are given in decimal notation in this
set of documents. All media type values, subtype values, and
parameter names as defined are case-insensitive. However, parameter
values ...
...
It is also worth noting that version control for specific media types
is not accomplished using the MIME-Version mechanism. In particular,
...
... conventions exist, MIME does nothing to supersede them. Where no
such conventions exist, a MIME media type might use a "version"
parameter in the content-type ...
... agent or mechanism to present the data to the
user, or otherwise deal with the data in an appropriate manner. The
value in this field is called a media type.
...
... header field specifies the nature of the data in the
body of an entity by giving media type and subtype identifiers, and
by providing auxiliary information that may be required for certain
...
... identifiers, and
by providing auxiliary information that may be required for certain
media types. After the media type and subtype names, the remainder
...
... by providing auxiliary information that may be required for certain
media types. After the media type and subtype names, the remainder
of the header field ...
...
In general, the top-level media type is used to declare the general
type of data, while the subtype specifies a specific format for that
type of data. Thus, a media type ...
... media type is used to declare the general
type of data, while the subtype specifies a specific format for that
type of data. Thus, a media type of "image/xyz" is enough to tell a
user agent ...
... media subtype, and as such do not
fundamentally affect the nature of the content. The set of
meaningful parameters depends on the media type and subtype. Most
parameters are associated with a single specific subtype. However, a
given top-level ...
... parameters are associated with a single specific subtype. However, a
given top-level media type may define parameters which are applicable
to any subtype of that type. Parameters may be required by their
defining content type ...
... charset" parameter is applicable to any subtype of
"text", while the "boundary" parameter is required for any subtype of
the "multipart" media type.
...
...
There are NO globally-meaningful parameters that apply to all media
types. Truly global mechanisms are best addressed, in the MIME
model, by the definition of additional Content-* header fields ...
...
An initial set of seven top-level media types is defined in RFC 2046draft.
Five of these are discrete types whose content is essentially opaque ...
...
This set of top-level media types is intended to be substantially
complete. It is expected that additions to the larger set of
supported types can generally be accomplished by the creation of new
...
... type "/" subtype *(";" parameter) ; Matching of media type and subtype is ALWAYS case-insensitive. ...
... The type, subtype, and parameter names are not case sensitive. For
example, TEXT, Text, and TeXt are all equivalent top-level media
types. Parameter values are normally case sensitive, but sometimes
are interpreted in a case-insensitive ...
... The second document in this set, RFC 2046draft, defines the initial set of
media types for MIME.
...
...
Many media types which could be usefully transported via email are
represented, in their "natural" format, as 8bit ...
... NOTE: The five values defined for the Content-Transfer-Encoding field
imply nothing about the media type other than the algorithm by which
it was encoded or the transport ...
...
Unlike media types and subtypes, the creation of new Content-
Transfer-Encoding values is STRONGLY discouraged, as it seems likely
...
...
It should be noted that most media types are defined in terms of
octets rather than bits, so that the mechanisms described here are
...
... mechanism for noting the addition of such padding in the case of the
application/octet-stream media type, which has a "padding" parameter.
...
... Certain Content-Transfer-Encoding values may only be used on certain
media types. In particular, it is EXPRESSLY FORBIDDEN to use any
encodings other than "7bit", "8bit ...
... 8bit", or "binary" with any composite
media type, i.e. one that recursively includes other Content-Type
fields. Currently the only composite ...
... Content-Type
fields. Currently the only composite media types are "multipart" and
"message". All encodings that are desired for bodies of type
...
... or, at the very least, that certain Content-Transfer-Encodings could
be mandated for use with specific media types. There are several
reasons why this is not the case. First, given the varying types of
transports ...
... transports used for mail, some encodings may be appropriate for some
combinations of media types and transports but not for others. (For
example, in an 8bit ...
...
Second, certain media types may require different types of transfer
encoding under different circumstances. For example, many PostScript
...
... specification mechanism, strict specification of an association
between media types and encodings effectively couples the
specification of an application protocol ...
... application protocol with a specific lower-level
transport. This is not desirable since the developers of a media
type should not have to be aware of all the transports in use and
what their limitations are.
...
... encoding. Since
the canonical representation of media types other than
text do not generally include the representation of
line breaks ...
... Content-ID header is generally optional, its use is MANDATORY in
implementations which generate data of the optional MIME media type
"message/external-body". That is, each message/external-body ...
... Content-ID value has special
semantics in the case of the multipart/alternative media type. This
is explained in the section of RFC 2046draft dealing with
...
... The next document in this set, RFC 2046draft, specifies the initial set of
media types that can be labelled and transported using these headers.
...
... type "/" subtype *(";" parameter) ; Matching of media type and subtype is ALWAYS case-insensitive. ...