diff options
Diffstat (limited to 'doc/rfc/rfc2079.txt')
-rw-r--r-- | doc/rfc/rfc2079.txt | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/doc/rfc/rfc2079.txt b/doc/rfc/rfc2079.txt new file mode 100644 index 0000000..f761d36 --- /dev/null +++ b/doc/rfc/rfc2079.txt @@ -0,0 +1,283 @@ + + + + + + +Network Working Group M. Smith +Request for Comments: 2079 Netscape Communications +Category: Standards Track January 1997 + + + Definition of an X.500 Attribute Type and an Object Class to Hold + Uniform Resource Identifiers (URIs) + +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. + +Abstract + + Uniform Resource Locators (URLs) are being widely used to specify the + location of Internet resources. There is an urgent need to be able + to include URLs in directories that conform to the LDAP and X.500 + information models, and a desire to include other types of Uniform + Resource Identifiers (URIs) as they are defined. A number of + independent groups are already experimenting with the inclusion of + URLs in LDAP and X.500 directories. This document builds on the + experimentation to date and defines a new attribute type and an + auxiliary object class to allow URIs, including URLs, to be stored in + directory entries in a standard way. + +Background and Intended Usage + + Uniform Resource Locators (URLs) as defined by [1] are the first of + several types of Uniform Resource Identifiers (URIs) being defined by + the IETF. URIs are widely used on the Internet, most notably within + Hypertext Markup Language [2] documents. This document defines an + X.500 [3,4] attribute type called labeledURI and an auxiliary object + class called labeledURIObject to hold all types of URIs, including + URLs. These definitions are designed for use in LDAP and X.500 + directories, and may be used in other contexts as well. + + + + + + + + + + + + +Smith Standards Track [Page 1] + +RFC 2079 URI Attribute Type and Object Class January 1997 + + +Schema Definition of the labeledURI Attribute Type + + Name: labeledURI + ShortName: None + Description: Uniform Resource Identifier with optional label + OID: umichAttributeType.57 (1.3.6.1.4.1.250.1.57) + Syntax: caseExactString + SizeRestriction: None + SingleValued: False + +Discussion of the labeledURI Attribute Type + + The labeledURI attribute type has the caseExactString syntax (since + URIs are case-sensitive) and it is multivalued. Values placed in the + attribute should consist of a URI (at the present time, a URL) + optionally followed by one or more space characters and a label. + Since space characters are not allowed to appear un-encoded in URIs, + there is no ambiguity about where the label begins. At the present + time, the URI portion must comply with the URL specification [1]. + Multiple labeledURI values will generally indicate different + resources that are all related to the X.500 object, but may indicate + different locations for the same resource. + + The label is used to describe the resource to which the URI points, + and is intended as a friendly name fit for human consumption. This + document does not propose any specific syntax for the label part. In + some cases it may be helpful to include in the label some indication + of the kind and/or size of the resource referenced by the URI. + + Note that the label may include any characters allowed by the + caseExactString syntax, but that the use of non-IA5 (non-ASCII) + characters is discouraged as not all directory clients may handle + them in the same manner. If non-IA5 characters are included, they + should be represented using the X.500 conventions, not the HTML + conventions (e.g., the character that is an "a" with a ring above it + should be encoded using the T.61 sequence 0xCA followed by an "a" + character; do not use the HTML escape sequence "å"). + +Examples of labeledURI Attribute Values + + An example of a labeledURI attribute value that does not include a + label: + + ftp://ds.internic.net/rfc/rfc822.txt + + + + + + + +Smith Standards Track [Page 2] + +RFC 2079 URI Attribute Type and Object Class January 1997 + + + An example of a labeledURI attribute value that contains a tilde + character in the URL (special characters in a URL must be encoded as + specified by the URL document [1]). The label is "LDAP Home Page": + + http://www.umich.edu/%7Ersug/ldap/ LDAP Home Page + + Another example. This one includes a hint in the label to help the + user realize that the URL points to a photo image. + + http://champagne.inria.fr/Unites/rennes.gif Rennes [photo] + +Schema Definition of the labeledURIObject Object Class + + Name: labeledURIObject + Description: object that contains the URI attribute type + OID: umichObjectClass.15 (1.3.6.1.4.1.250.3.15) + SubclassOf: top + MustContain: + MayContain: labeledURI + +Discussion of the labeledURIObject Object Class + + The labeledURIObject class is a subclass of top and may contain the + labeledURI attribute. The intent is that this object class can be + added to existing directory objects to allow for inclusion of URI + values. This approach does not preclude including the labeledURI + attribute type directly in other object classes as appropriate. + +Security Considerations + + Security considerations are not discussed in this memo, except to + note that blindly inserting the label portion of a labeledURI + attribute value into an HTML document is not recommended, as this may + allow a malicious individual to include HTML tags in the label that + mislead viewers of the entire document in which the labeledURI value + was inserted. + +Acknowledgments + + Paul-Andre Pays, Martijn Koster, Tim Howes, Rakesh Patel, Russ + Wright, and Hallvard Furuseth provided invaluable assistance in the + creation of this document. + + This material is based in part upon work supported by the National + Science Foundation under Grant No. NCR-9416667. + + + + + + +Smith Standards Track [Page 3] + +RFC 2079 URI Attribute Type and Object Class January 1997 + + +Appendix: The labeledURL Attribute Type (Deprecated) + + An earlier draft of this document defined an additional attribute + type called labeledURL. This attribute type is deprecated, and + should not be used when adding new values to directory entries. The + original motivation for including a separate attribute type to hold + URLs was that this would better enable efficient progammatic access + to specific types of URIs. After some deliberation, the IETF-ASID + working group concluded that it was better to simply have one + attribute than two. + + The schema definition for labeledURL is included here for historical + reference only. Directory client software may want to support this + schema definition (in addition to labeledURI) to ease the transition + away from labeledURL for those sites that are using it. + + Name: labeledURL + ShortName: None + Description: Uniform Resource Locator with optional label + OID: umichAttributeType.41 (1.3.6.1.4.1.250.1.41) + Syntax: caseExactString + SizeRestriction: None + SingleValued: False + OID: umichAttributeType.41 (1.3.6.1.4.1.250.1.41) + +References + + [1] Berners-Lee, T., Masinter, L., and M. McCahill, "Uniform + Resource Locators (URL)", RFC 1738, CERN, Xerox Corporation, + University of Minnesota, December 1994. + <URL:ftp://ds.internic.net/rfc/rfc1738.txt> + + [2] Berners-Lee, T., and D. Connolly, "Hypertext Markup Language - + 2.0", RFC 1866, <URL:ftp://ds.internic.net/rfc/rfc1866.txt> + + [3] The Directory: Overview of Concepts, Models and Service. CCITT + Recommendation X.500, 1988. + + [4] Information Processing Systems -- Open Systems Interconnection -- + The Directory: Overview of Concepts, Models and Service. ISO/IEC JTC + 1/SC21; International Standard 9594-1, 1988. + + + + + + + + + + +Smith Standards Track [Page 4] + +RFC 2079 URI Attribute Type and Object Class January 1997 + + +Author's Address + + Mark Smith + Netscape Communications Corp. + 501 E. Middlefield Rd. + Mountain View, CA 94043, USA + + Phone: +1 415 937-3477 + EMail: mcs@netscape.com + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Smith Standards Track [Page 5] + |