media type
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... MIME entity, by
giving media type and subtype identifiers, and by providing auxiliary
information that may be required for certain media types ...
... media type and subtype identifiers, and by providing auxiliary
information that may be required for certain media types. After the
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 media type ...
... media type may define parameters which are applicable
to any subtype of that type. Parameters may be required by their
defining media type or subtype or they may be optional. MIME
implementations must also ignore any parameters whose names they do
...
... MIME's Content-Type header field and media type mechanism has been
carefully designed to be extensible, and it is expected that the set
of media type ...
... media type mechanism has been
carefully designed to be extensible, and it is expected that the set
of media type/subtype pairs and their associated parameters will grow
significantly over time. Several other MIME facilities, such as
...
...
The initial seven standard top-level media type are defined and
described in the remainder of this document.
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... Definition of a Top-Level Media Type ...
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The definition of a top-level media type consists of:
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... Overview Of The Initial Top-Level Media Types ...
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The five discrete top-level media types are:
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message -- an encapsulated message. A body of media
type "message" is itself all or a portion of some kind
of message object. Such objects may or may not in turn
contain other entities. The "rfc822" subtype is used
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It should be noted that the list of media type values given here may
be augmented in time, via the mechanisms described above, and that
the set of subtypes is expected to grow substantially.
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... Discrete Media Type Values ...
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Five of the seven initial media type values refer to discrete bodies.
The content of these types must be handled by non-MIME mechanisms;
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... Text Media Type ...
...
The "text" media type is intended for sending material which is
principally textual in form. A "charset" parameter may be used to
...
... NOTE: The proper interpretation of line breaks when a body is
displayed depends on the media type. In particular, while it is
appropriate to treat a line break as a transition to a new line when
...
... Similarly, whether or not line breaks should be added during display
operations is also a function of the media type. It should not be
necessary to add any line breaks to display "text/plain ...
...
Other media types than subtypes of "text" might choose to employ the
charset parameter as defined here, but with the CRLF ...
... user agents explicitly
specify a character set as a media type parameter in the Content-Type
header field ...
... version of the American Standard. Insofar as one of the purposes of
specifying a media type and character set is to permit the receiver
...
... specifications, processing instructions, interpretation directives,
or content markup should be necessary for proper display. The
default media type of "text/plain; charset=us-ascii" for Internet
mail ...
... Image Media Type ...
... Audio Media Type ...
... Video Media Type ...
...
A media type of "video" indicates that the body contains a time-
varying-picture image, possibly with color and coordinated sound ...
... Application Media Type ...
...
The "application" media type is to be used for discrete data which do
not fit in any of the other categories, and particularly for data to
be processed by some type of application program. This is
...
... information which must be processed by an application before it is
viewable or usable by a user. Expected uses for the "application"
media type include file transfer, spreadsheets, data for mail-based
scheduling systems, and languages ...
...
Such applications may be defined as subtypes of the "application"
media type. This document defines two subtypes:
...
... registered trademark of Adobe Systems, Inc. Use of
the MIME media type "application/postscript" implies recognition of
that trademark and all the rights it entails.
...
... Composite Media Type Values ...
... Multipart Media Type ...
...
In the case of multipart entities, in which one or more different
sets of data are combined in a single body, a "multipart" media type
field must appear in the entity's header ...
...
The use of a media type of "multipart" in a body part within another
"multipart" entity is explicitly allowed. In such cases, for obvious
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The use of the "multipart" media type with only a single body part
may be useful in certain contexts, and is explicitly permitted.
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NOTE: Experience has shown that a "multipart" media type with a
single body part is useful for sending non-text media types. It has
...
... NOTE: Experience has shown that a "multipart" media type with a
single body part is useful for sending non-text media types. It has
the advantage of providing the preamble as a place to include
decoding instructions. In addition, a number of SMTP ...
...
The only mandatory global parameter for the "multipart" media type is
the boundary parameter, which consists of 1 to 70 characters from a
set of characters known to be very robust through mail gateways ...
... Message Media Type ...
... encapsulate another
mail message. A special media type, "message", is defined to
facilitate this. In particular, the "rfc822" subtype of "message" is
used to encapsulate ...
...
A media type of "message/rfc822" indicates that the body contains an
encapsulated message, with the syntax of an RFC 822std11(-> 2822prop) ...
... transport agents limit the
size of individual messages that can be sent. The media type
"message/partial" thus indicates that the body contains a fragment of
...
... content-type header field. Instead,
it is provided as the "phantom body" when the media type is
"message/external-body" and the access-type is mail-server.
...
... When the external-body mechanism is used in conjunction with the
"multipart/alternative" media type it extends the functionality of
"multipart/alternative" to include the case where the same entity is
...
... message header fields which appear in the body of the
"message/external-body" data must be used to declare the media type
of the external body if it is anything other than plain US-ASCII
text, since the external body does not have a header ...
...
Like the "message/partial" type, the "message/external-body" media
type is intended to be transparent, that is, to convey the data type
in the external body rather than to convey a message with a body of
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... Experimental Media Type Values ...
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A media type value beginning with the characters "X-" is a private
value, to be used by consenting systems by mutual agreement. Any
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...
The five discrete media types provide provide a standardized
mechanism for tagging entities as "audio", "image ...
... image", or several other
kinds of data. The composite "multipart" and "message" media types
allow mixing and hierarchical structuring of entities of different
types in a single message. A distinguished parameter syntax allows
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... header fields provide mechanisms for certain extensions deemed
desirable by many implementors. Finally, a number of useful media
types are defined for general use by consenting user agents, notably
"message/partial" and "message/external-body ...
... Implementors should pay special attention to the
security implications of any media types that can cause the remote
execution of any actions in the recipient's environment. In such
cases, the discussion ...
... discussion of the "application/postscript" type may serve
as a model for considering other media types with remote execution
capabilities.
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