MIME
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... application/xml-dtd -- as
well as a naming convention for identifying XML-based MIME media
types.
...
... these parameters, it would be ambiguous if such parameters were given
for an XML MIME entity. For these reasons, the best approach for
labeling XML ...
...
As sometimes happens between two communities, both MIME and XML have
defined the term entity ...
...
"The term 'entity' refers specifically to the MIME-defined header
fields and contents of either a message or one of the parts in the
body of a multipart entity ...
... This document standardizes five media types related to XML MIME
entities: text/xml, application/xml, text/xml-external-parsed-entity,
...
... Within the XML specification, XML MIME entities can be classified
into four types. In the XML terminology, they are called "document
...
... internal parsed entities, and internal parameter entities, but they
are not XML MIME entities.
...
... -- is readable by casual users, text/xml is preferable to
application/xml. MIME user agents (and web user agents) that do not
...
... Application/xml is preferable when the XML MIME entity is unreadable
by casual users. Similarly, text/xml-external-parsed-entity ...
... The top-level media type "text" has some restrictions on MIME
entities and they are described in [RFC2045] and [RFC2046]. In
...
... (except over HTTP[RFC2616], which uses a MIME-like mechanism). Thus,
if an XML document or external parsed entity ...
...
MIME media type name: text
MIME subtype name ...
... XML processors to determine authoritatively the character
encoding of the XML MIME entity. The charset parameter can also
...
... entity is transmitted via HTTP, which uses a
MIME-like mechanism that is exempt from the restrictions on the
text top-level type (see section 19.4.1 of [RFC2616 ...
... CR, LF and
NUL for text types in most MIME applications would cause undesired
transformations of individual octets in UTF-16 multi-octet
...
... UTF-8
and ISO-8859-1 and since it is already used by MIME.)
There are several reasons that the charset parameter ...
... There are several reasons that the charset parameter is
authoritative. First, some MIME processing engines do transcoding
of MIME bodies of the top-level ...
... authoritative. First, some MIME processing engines do transcoding
of MIME bodies of the top-level media type "text" without
...
... XML document. Second, text/xml must be
compatible with text/plain, since MIME agents that do not
understand text/xml will fallback to handling it as text/plain ...
... XML encoding declaration. Thus, special
care is needed when the recipient strips the MIME header and
provides persistent storage of the received XML MIME ...
... MIME header and
provides persistent storage of the received XML MIME entity (e.g.,
in a file system ...
... appropriate for the charset and the capabilities of the underlying
MIME transport. For 7-bit transports ...
... Although no byte sequences can be counted on to always be
present, XML MIME entities in ASCII-compatible charsets
...
...
MIME media type name: application
MIME subtype name ...
... charset
parameter is omitted, no information is being provided about the
charset by the MIME Content-Type header. Conforming XML
processors MUST follow the requirements ...
... XML]
that directly address this contingency. However, MIME processors
that are not XML processors ...
... XML encoding declaration. Thus, special
care is needed when the recipient strips the MIME header and
provides persistent storage of the received XML MIME ...
... MIME header and
provides persistent storage of the received XML MIME entity (e.g.,
in a file system ...
... appropriate for the charset and the capabilities of the underlying
MIME transport. For 7-bit transports ...
...
MIME media type name: text
MIME subtype name ...
...
MIME media type name: application
MIME subtype name ...
...
MIME media type name: application
MIME subtype name ...
... Section 4.3.3 of [XML] specifies that XML MIME entities in the
charset "utf-16" MUST begin with a byte order mark ...
... prohibited for these charsets. When an XML MIME entity is encoded in
"utf-16le" or "utf-16be", it MUST NOT begin with the BOM ...
... semantics of a relative
URI reference embedded in a MIME entity is dependent on the base URI.
...
... entity, (3) the URI used
to retrieve the MIME entity, or (4) the application-dependent default
base URI, where (1) has the highest precedence. [RFC2396 ...
... embedding the base URI in XML MIME entities. However, a Proposed
Recommendation published by W3C, namely "XML ...
... suffix of
'+xml') for identifying XML-based MIME media types, whatever their
particular content may represent. This allows the use of generic XML
processors and technologies on a wide variety of different XML
document ...
... Although the use of a suffix was not considered as part of the
original MIME architecture, this choice is considered to provide the
most functionality with the least potential for interoperability ...
... rapidly. Many of these XML document types would benefit from the
identification possibilities of a more specific MIME media type than
text/xml or application/xml can provide, and it is likely that many
...
...
While the benefits of specific MIME types for particular types of XML
documents are significant, all XML documents share common structures
...
... media type SHOULD end with '+xml'. This convention will allow
applications that can process XML generically to detect that the MIME
entity is supposed to be an XML document ...
... accordingly. Applications may match for types that represent XML
MIME entities by comparing the subtype to the pattern '*/*+xml'. (Of
course, 4 of the 5 media types defined in this document -- text/xml,
...
... application/xml-external-parsed-entity -- also represent XML MIME
entities while not conforming to the '*/*+xml' pattern.)
...
... interoperability of their XML-based
documents. Similarly, media subtypes that do not represent XML MIME
entities MUST NOT be allowed to register with a '+xml' suffix.
...
... XML declaration is assumed
to come at the beginning of the XML MIME entity, immediately
following the BOM ...
... entity, immediately
following the BOM. Note that other MIME headers may be present, and
the XML MIME ...
... MIME headers may be present, and
the XML MIME entity may contain other data in addition to the XML
declaration; the examples focus on the Content-type ...
... charset value for use with text/xml. Since
the charset parameter is provided, MIME and XML processors MUST treat
the enclosed entity ...
... entity is transmitted via
HTTP, which uses a MIME-like mechanism and is a binary-clean
protocol, hence does not perform CR and LF ...
... BOM does not exist. This is again possible only
when the XML MIME entity is transmitted via HTTP.
...
... encoded following the specification in [RFC1557]. Since the charset
parameter is provided, MIME and XML processors MUST treat the
enclosed entity ...
... This example shows text/xml with the charset parameter omitted. In
this case, MIME and XML processors MUST assume the charset is "us-
...
... charset parameter is NOT RECOMMENDED for text/xml. For
example, even if the contents of the XML MIME entity are UTF-16 or
...
... application/xml.
Since the charset parameter is provided, MIME and XML processors MUST
treat the enclosed entity ...
... BOM does not exist. Since the charset parameter is
provided, MIME and XML processors MUST treat the enclosed entity as
...
... RFC1557]. Since the
charset parameter is provided, MIME and XML processors MUST treat the
enclosed entity ...
... 1557, independent of whether the
XML MIME entity has an internal encoding declaration (this example
...
... entity. Since the charset parameter is provided,
MIME and XML processors MUST treat the enclosed entity as UTF-8 ...
... entity. Since the charset parameter is provided,
MIME and XML processors MUST treat the enclosed entity as UTF-16 ...
...
Since the charset parameter is provided, MIME and XML processors MUST
treat the enclosed entity ...
... application/xml-dtd. Since the charset parameter is provided, MIME
and XML processors MUST treat the enclosed entity ...
... based
on XML, MathML documents SHOULD use the '+xml' suffix convention in
their MIME content-type identifier. However, no content type has yet
...
... XSLT documents SHOULD
use the '+xml' suffix convention in their MIME content-type
identifier. However, no content type ...
...
RDF documents identified using this MIME type are XML documents whose
content describes metadata, as defined by [RDF ...
... RDF documents SHOULD use the '+xml' suffix convention in
their MIME content-type identifier. However, no content type has yet
...
... based on XML, SVG documents SHOULD use the '+xml' suffix
convention in their MIME content-type identifier. However, no
content type ...
... Processors generating XML MIME entities MUST NOT label conflicting
charset information between the MIME Content ...
... MIME entities MUST NOT label conflicting
charset information between the MIME Content-Type and the XML
declaration.
...
... To paraphrase section 3 of RFC 1874exp, XML MIME entities contain
information to be parsed and processed by the recipient's XML system.
...
... XML system will execute arbitrary command strings,
recipients of XML MIME entities may be a risk. In general, it may be
possible to specify commands that perform unauthorized file
operations or make changes to the display processor ...
... Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045draft, November 1996. ...
... Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046draft, November 1996. ...
... Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures", RFC 2048(-> 4289 | 4288), November 1996. ...
... Although the use of a suffix was not considered as part of the
original MIME architecture, this choice is considered to provide the
most functionality with the least potential for interoperability ...
... XML-based format
such as image/svg+xml fits the definition of a MIME media type
exactly as well as image/png[PNG ...
... image/svg+xml is
not yet registered.) Although extra functionality is available for
MIME processors that are also XML processors, XML-based ...
...
Since MIME dispatchers work off of the MIME type, use of text/xml or
application/xml to label discrete media types ...
... subtree, those types may
remain in the same location in the tree of MIME types that they would
have occupied had they not been based on XML.
...
...
The top-level MIME type (e.g., model/*[RFC2077]) determines what kind
of content the type is, not what syntax it uses. For example, agents ...
... Although this method might work acceptably for some mail
applications, it would fail completely in many other uses of MIME.
For instance, an XML-based web crawler would have no way of
...
... RFC2060] mail applications, where
the client first fetches the MIME type as part of the message
structure and then decides whether to fetch the MIME entity ...
... client first fetches the MIME type as part of the message
structure and then decides whether to fetch the MIME entity.
Requiring these fetches just to determine whether the MIME type ...
... MIME entity.
Requiring these fetches just to determine whether the MIME type is
XML could have significant bandwidth ...
... media types are by their nature
always XML. Parameters, as they have been defined in the MIME
architecture, are never invariant across all instantiations of a
...
...
More practically, very few if any MIME dispatchers and other MIME
agents support dispatching off of a parameter. While MIME ...
... knowledge of XML nor an XML-capable MIME dispatcher. In that case,
the user's MIME dispatcher is likely to dispatch the content to an
...
... XML-capable MIME dispatcher. In that case,
the user's MIME dispatcher is likely to dispatch the content to an
XML processing application when the correct default behavior should
...
... Note that even if the user had already installed the appropriate
application (e.g., the ecommerce engine), and that installation had
updated the MIME registry, many operating system level MIME ...
... MIME registry, many operating system level MIME
registries such as .mailcap in Unix and HKEY_CLASSES ...
... easily be upgraded to do so. And, even if the operating system were
upgraded to support this, each MIME dispatcher would also separately
need to be upgraded.
...
... A.7 How about a new superclass MIME parameter that is defined to apply
to all MIME types (e.g., Content-Type ...
... A.7 How about a new superclass MIME parameter that is defined to apply
to all MIME types (e.g., Content-Type: application/iotp;
$superclass=xml)? ...
... includes the instructions "Please copy the French text on the road
sign", someone with an XML-aware MIME client and an XML browser but
...
... receivers to be upgraded, and few if any
operating systems and MIME dispatchers support working off of
anything other than the MIME type.
...
... operating systems and MIME dispatchers support working off of
anything other than the MIME type.
...
...
This is better than Appendix A.8, in that no extra functionality
needs to be added to a MIME registry to support dispatching of
information other than standard content types ...
... fail in many cases (e.g., web hosting to an outsourced server), where
the user can set MIME types (often through implicit mapping to file
extensions), but has no way of adding arbitrary HTTP headers.
...
... opaque and continue to
interoperate. By contrast, adding a third-level type would break the
current MIME architecture and cause numerous interoperability
failures.
...
...
It was thought that '+' expressed the semantics that a MIME type can
be treated (for example) as both scalable vector graphics ...
...
In the ten years that MIME has existed, XML is the first generic data
format that has seemed to justify special treatment, so it is hoped
...