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Comments on draft-ietf-http-v10-spec-00.ps

From: David Robinson <drtr1@cam.ac.uk>
Date: Tue, 2 May 95 15:29 BST
Message-Id: <m0s6IxW-0007bBC@grus.cus.cam.ac.uk>
To: http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com
Cc: drtr1@cus.cam.ac.uk
Some comments on the HTTP/1.0 spec from 8th March.

2.1 `Augmentent BNF'
The spec describes where whitespace is allowed:

   implied *LWS
      The grammar described by this specification is word-based. Except where
      noted otherwise, zero or more linear whitespace (LWS) can be included
      between any two words (token or quoted-string) without changing the
      interpretation of a field.

Presumably the words have to be adjacent!
This rule does not allow LWS in places where it should, i.e. between a word
and a tspecial in some circumstances.
Specifically:
* after ":" in a header:
  from section 4.2 `Message Headers'
     HTTP-header = field-name ":" [field-value] CRLF
  does not allow LWS between the ":" and the field value; neither does the
  specifications for individual headers.
* after ";" in media-type values:
  e.g. section 5.4.1 `Accept' defines the header as
     Accept  = "Accept" ":" 1# (
                  media-range
                  [";" "q" "=" ("0" | "1" | float)]
                  [";" "mxb" "=" 1*DIGIT])
     media-range = ( "*/*" | ( type "/" "*" ) | ( type "/" subtype ) )
                   * (";" parameter )
  this does not allow LWS between the ";" and the q, mxb or other parameters.
  Similarly in sections 7.1.10 `Link', 7.1.13 `URI', 8.1 `Media Types'.

2.2 `Basic Rules'

      OCTET    = <any 8-bit character>
                            ~~~~~~~~~

   The text rule is only used for descriptive field contents. Words of *text
   may contain characters from character sets other than US-ASCII only when
   encoded according to the rules of RFC 1522 [13].

      text     = <any OCTET except CTLs, but including LWS>
                      ~~~~~

Is it necessary to allow any OCTET in `text', rather than just any CHAR?
It isn't defined what character set these 8-bit characters come from.
I suggest either changing the OCTET rule to be 'any 8-bit ISO-Latin-1
character', or avoiding using OCTET anywhere in a header specification.
(I would much prefer the latter.)

4.2 `Message-Headers'

Although the specification for the individual headers use case insensitive
names, it should be specified in section 4.2 that field-name is case
insensitive. Otherwise an extension-header could have a case sensitive name.

5.3 `Request-URI'

   The Request-URI is a Universal Resource Identifier (Section 3.2) and
   identifies the resource upon which to apply the request.

      Request-URI   = URI

   Unless the server is being used as a proxy, a partial URI shall be given
                                               ~~~~~~~~~~~~~
   with the assumptions of the scheme (http) and hostname:port (the server's
   address) being obvious. That is, if the full URI looks like

      http://info.cern.ch/hypertext/WWW/TheProject.html

   then the corresponding partial URI in the Simple-Request or Full-Request is

      /hypertext/WWW/TheProject.html

I don't think that `partial URI' is either properly or correctly defined.

`A partial URI' is not defined by the HTTP spec, nor is a reference given.
The term `partial URI' is mentioned in RFC 1630, and sounds synonymous
with a `relative URL', which is defined (differently) in
draft-ietf-uri-relative-url-06.txt. Taking the latter definition,
  //info.cern.ch/hypertext/WWW/TheProject.html   and
  hypertext/WWW/TheProject.html
 are also relative URLs for the document. Avoiding the first possiblity by
restricting `partial URI' to be an `abs_path relative URL' [Roy Fielding,
pers. comm.] helps, but there is then the problem that an abs_path cannot
start with "//". Thus transfer of URIs like http://host.name//void would be
impossible. Also, is a empty string allowed for `partial URI'?

I would suggest codifying the current common browser behaviour, which is:
1. Remove the scheme-part, the "://" and the hostport part from the URI.
2. If the partial URI does not begin with a "/", then preprend a "/"

Rule 2 is only ever applied if the path component of the URI is void.
[I note that the URI spec (RFC 1630) allows http://host.name?search whereas
 the URL spec (RFC 1738) does not.]
As http://host.name and http://host.name/ are supposed to be identical URIs,
it makes sense to specify a single partial URI for both of them.

10. `Access Authentication'

This doesn't state whether auth-scheme is case-insensitive or not. It has
   auth-scheme = "Basic" | token
Thus the value "Basic" is case insensitive (see section 2.1), but other
values are not.

  David Robinson.
Received on Tuesday, 2 May 1995 07:31:22 EDT

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