- From: Roy T. Fielding <fielding@avron.ICS.UCI.EDU>
- Date: Wed, 18 Jan 1995 02:43:45 -0800
- To: http working group <http-wg%cuckoo.hpl.hp.com@hplb.hpl.hp.com>
>> > The grammar for the User-Agent header currently reads like this: >> > >> > > User-Agent = "User-Agent" ":" 1*( product ) >> > > >> > > product = token ["/" product-version] >> > > product-version = 1*DIGIT "." 1*DIGIT > ... >> > >> Sounds fair - what about: >> >> User-Agent = "User-Agent" ":" 1*( product ) >> product = token ["/" token] I can live with User-Agent = "User-Agent" ":" 1*( product ) product = token ["/" product-version] product-version = token Note, however, that token has a restricted set of allowed characters as specified in the BNF. The reason product-version is separate is so that I can explicitly state what is not allowed in the version from a semantic point-of-view. > Yes, where token is any string of characters which doesn't require URL > encoding *OR* any string of characters inside of quotes. User-Agent > should be required to be a unique identifier for a particular version > of User-Agent. The standard should be absolutely relaxed about the > format of the identifer except that it should be allowed to inhibit > proper parsing of subsequent headers. Might include words to describe > how to insure uniqueness? Or leave it to follow the course of domain > names. Or register the unique portion of the ID, etc.. None of the above. The HTTP protocol will assume that client authors will want to give their products suitable product tokens. Requiring a registry will not work due to the overhead and market considerations. However, it would be nice if W3C set up a voluntary registry. > It should be recommended that a human be able to read the string and > relate it to external version control parameters. Nope. This string is explicitly not intended for human readability. ......Roy Fielding ICS Grad Student, University of California, Irvine USA <fielding@ics.uci.edu> <URL:http://www.ics.uci.edu/dir/grad/Software/fielding>
Received on Wednesday, 18 January 1995 02:49:43 UTC