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Network Working Group                                        R. Van Rein
Internet-Draft                                          InternetWide.org
Intended status: Standards Track                        January 23, 2020
Expires: July 26, 2020

                   User Names for HTTP Resource Views


   Most protocols support users under domain names, but HTTP is an
   exception.  Given that it is useful to have this facility for HTTP
   and that it merely requires a consistent treatment by clients, we
   specify how to map such URI patterns to HTTP Requests.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on July 26, 2020.

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   Copyright (c) 2020 IETF Trust and the persons identified as the
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  The HTTP User-View Header . . . . . . . . . . . . . . . . . .   2
   3.  Protocol Handling of User-View  . . . . . . . . . . . . . . .   3
   4.  Caching Behaviour . . . . . . . . . . . . . . . . . . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   Most protocols support Network Access Identifiers like
   john@example.com to identify users like john within domains such as
   example.com.  The URI format for HTTP can express such authority
   sections, and many online applications seem to want to address
   individual users, but HTTP offers no representation for user names.
   This specification solves that with a new header.

   Historically, user names have been derived from (Basic and Digest)
   authentication.  This is not generally correct; the user name in the
   URI represents the resource, not the visitor.  The use of a new
   header allows indepedency between authentication and resource

   Browsers have supported (Basic and Digest) authentication with a
   scheme of "user:password" in the authority section of URIs.  This has
   now been deprecated [Section 3.2.1 of [RFC3986]] but the form with
   just "user" but not ":password" is still open to use.  Various HTTP
   clients have different handling of this form, sometimes flagging it
   incorrectly as a security hazard, which is another reason to specify
   what to do.

   The purpose of this specification is to give a clear meaning to a URI
   with a user name portion, but with no password.  Such a URI may be
   implemented by variation of the HTTP resource space, just as is often
   done for host name.

2.  The HTTP User-View Header

   The "User-View" header field in a request provides the user name from
   the target URI.  The value is taken from the userinfo in the
   authority section [Section 3.2 of [RFC3986]] which MUST NOT include a
   colon.  An empty header value indicates absense of a user name.  The
   header value holds precisely one value with the following ABNF

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   User-View = 0*( unreserved / pct-encoded / sub-delims )

   The referenced non-terminals are as for URIs [RFC3986].

   The User-View header MAY occur in requests and responses, but MUST
   NOT be included in trailers [Section 4.1 of [RFC7230]].

3.  Protocol Handling of User-View

   User agents SHOULD render user names in authority sections as they do
   host names.  User agents SHOULD NOT remove user names from the URI.
   User agents MAY remove the "@" symbol (U+0040) from a URI when the
   preceding user name is empty.  User agents SHOULD indicate
   deprecation of the form "user:password" and MUST NOT complain in any
   way about a user name that adheres to the above grammar.

   HTTP servers SHOULD NOT use the User-View in responses except when
   responding to a user agent known to support it, possibly because they
   sent the User-View header in a request.

   When the User-View header is included in a response, it declares that
   any references relative to the resource returned should consider the
   returned user name part of the origin of the relative reference
   [Section 4.2 of [RFC3986]], inasfar as no authority information is
   provided in the relative reference.

   An empty User-View header value in a response indicates absense of a
   user name, due to removal relative to a request.  User agents
   receiving a User-View as part of an HTTP redirect [Section 6.4 of
   [RFC7231]] MUST update the user name in the URI accordingly when the
   authority part of the URI is not replaced as part of a new URI

   HTTP servers MAY redirect a request to a location that encodes the
   user name in the path of the URI, possibly setting the User-View
   header to an empty value.  This allows sites to define their own path
   syntax for user names, without users or tools needing to be aware of
   such local conventions.

   Whether a User-View header is used after a redirect, and what value
   it has, is determined by the target URI after its construction from
   the redirection and, possibly, the previous target URI.  This means
   that the User-View header MUST NOT be carried from a redirection
   response to its follow-up request, but instead freshly constructed.

   Intermediates MUST NOT add, remove or modify the User-View header.

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4.  Caching Behaviour

   The privacy or security of an HTTP resource does not change if it
   uses an additional User-View header.  This is because the header
   addresses a resource location, but is independent of authentication
   or authorisation, for which other headers are in use.

   HTTP caches [RFC7234] need to distinguish responses when they are
   requested with different User-View header values.  To this end, the
   Vary header [Section 7.1.4 of [RFC7231]] MUST be present, and MUST
   either be valued "*" or include the "user-view" token, for any
   response that has been influenced by a User-View header.  Software or
   configurations that ignore the header are not under this requirement.

5.  IANA Considerations

   IANA adds the following entry to the Message Headers registry:

   Header Field Name   Template   Protocol   Status    Reference
   ------------------  ---------  ---------  -------   ----------
   User-View                      http       TBD       TBD:THIS_SPEC

6.  Security Considerations

   The user names in HTTP URIs as defined herein is not related to
   authentication or authorisation, and implies no security concerns.

   These user names refine the model of resource addressing for HTTP,
   but any concerns related to privacy or secrecy of resources are
   already habitually addressed in HTTP servers.  This habit MUST be
   applied to this new, more refined resource addressing model.

7.  Normative References

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,

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   [RFC7234]  Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
              Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
              RFC 7234, DOI 10.17487/RFC7234, June 2014,

Author's Address

   Rick van Rein
   Haarlebrink 5
   Enschede, Overijssel  7544 WP
   The Netherlands

   Email: rick@openfortress.nl

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