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[Bug 9530] New: Validity of meta "pragmas"

From: <bugzilla@jessica.w3.org>
Date: Thu, 15 Apr 2010 14:14:04 +0000
To: public-html-bugzilla@w3.org
Message-ID: <bug-9530-2486@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=9530

           Summary: Validity of meta "pragmas"
           Product: HTML WG
           Version: unspecified
          Platform: PC
        OS/Version: Windows NT
            Status: NEW
          Severity: normal
          Priority: P2
         Component: HTML5 spec bugs
        AssignedTo: dave.null@w3.org
        ReportedBy: julian.reschke@gmx.de
         QAContact: public-html-bugzilla@w3.org
                CC: ian@hixie.ch, mike@w3.org, public-html@w3.org


"4.2.5.4 Other pragma directives" restricts the set of allowed values in
http-equiv:

"Extensions to the predefined set of pragma directives may, under certain
conditions, be registered in the WHATWG Wiki PragmaExtensions page.
[WHATWGWIKI]

Such extensions must use a name that is identical to an HTTP header registered
in the Permanent Message Header Field Registry, and must have behavior
identical to that described for the HTTP header. [IANAPERMHEADERS]

Pragma directives corresponding to headers describing metadata, or not
requiring specific user agent processing, must not be registered; instead, use
metadata names. Pragma directives corresponding to headers that affect the HTTP
processing model (e.g. caching) must not be registered, as they would result in
HTTP-level behavior being different for user agents that implement HTML than
for user agents that do not.

Anyone is free to edit the WHATWG Wiki PragmaExtensions page at any time to add
a pragma directive satisfying these conditions. Such registrations must specify
the following information:

Keyword

    The actual name being defined. The name must match a previously-registered
HTTP name with the same requirements.
Brief description

    A short non-normative description of the purpose of the pragma directive.
Specification
    A link to the specification defining the corresponding HTTP header.

Conformance checkers must use the information given on the WHATWG Wiki
PragmaExtensions page to establish if a value is allowed or not: values defined
in this specification or listed on the aforementioned page must be accepted,
whereas values not listed in either this specification or on the aforementioned
page must be rejected as invalid. Conformance checkers may cache this
information (e.g. for performance reasons or to avoid the use of unreliable
network connectivity)."

Problems:

#1: Validity depends on the current content of the Wiki registry. I'd like to
see proof that conformance checkers are actually going to implement this.

#2: There is no registration procedure. If anybody can add, can anybody remove
as well?

#3: The whole concept is in conflict with HTML4, which delegated the contents
of http-equiv directly to the related IETF specs

#4: The registry procedure on the referenced Wiki page is out-of-sync with the
spec text, it claims "...Such extensions are limited to previously-registered
HTTP headers defined in an RFC, ..."

#5: The specification link on the registry page refers to a different document
outside the W3C spec, so not the HTML5 spec.

#6: It's not clear at all that requiring an entry in the permanent registry is
required.

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Received on Thursday, 15 April 2010 14:18:05 GMT

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