Definition of the URL MIME External-Body Access-Type (RFC2017)
Original Publication Date: 1996-Oct-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
N. Freed: AUTHOR [+3]
This memo defines a new access-type for message/external-body MIME parts for Uniform Resource Locators (URLs). URLs provide schemes to access external objects via a growing number of protocols, including HTTP, Gopher, and TELNET. An initial set of URL schemes are defined in RFC 1738.
Network Working Group N. Freed
Request for Comments: 2017 Innosoft International
Category: Standards Track K. Moore
University of Tennessee
A. Cargille, WG Chair
Definition of the URL
MIME External-Body Access-Type
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
This memo defines a new access-type for message/external-body MIME
parts for Uniform Resource Locators (URLs). URLs provide schemes to
access external objects via a growing number of protocols, including
HTTP, Gopher, and TELNET. An initial set of URL schemes are defined
in RFC 1738.
The Multipurpose Internet Message Extensions (MIME) define a facility
whereby an object can contain a reference or pointer to some form of
data rather than the actual data itself. This facility is embodied in
the message/external-body media type defined in RFC 1521. Use of
this facility is growing as a means of conserving bandwidth when
large objects are sent to large mailing lists.
Each message/external-body reference must specify a mechanism whereby
the actual data can be retrieved. These mechanisms are called access
types, and RFC 1521 defines an initial set of access types: "FTP",
"ANON-FTP", "TFTP", "LOCAL-FILE", and "MAIL-SERVER".
Uniform Resource Locators, or URLs, also provide a means by which
remote data can be retrieved automatically. Each URL string begins
with a scheme specification, which in turn specifies how the
remaining string is to be used in conjunction with some protocol to
retrieve the data. However, URL schemes exist for protocol operations
that have no corresponding MIME message/external-body access type.
Registering an access type for URLs therefore provides
message/external-body with access to the retrieval mechanisms of URLs
that are not currently available as access types. It also provides
access to any future mechanisms for which URL schemes are developed.
This access type is only intended for use with URLs that actually
retreive something. Other URL mechansisms, e.g. mailto, may not be
used in this context.
3. Definition of the URL Access-Type
The URL access-type is defined as follows:
(1) The name of the access-type is URL.
(2) A new message/external-body content-type parameter is
used to actually store the URL string. The name of the
parameter is als...