HTTP Meeting Notes Monday Dec 9th

Chair: Larry Masinter,

Note taker: Henrik Frystyk Nielsen

HTTP/1.1 Implementation Issues

Performance Evaluation of HTTP/1.1 pipelining

• Henrik Frystyk Nielsen and Jim Gettys presented HTTP pipelining performance experimentations. It shows up to a factor of 5 in gain in number of packets. The slides from the presentation are available and also a paper describing the experiments in details.

What should a server respond to an HTTP/1.0 request?

• There are both clients and servers that choke on HTTP/1.1
• It's too late to fix alrady existing implementations
• If we don't say that we can do HTTP/1.1 then a client may never find out that a HTTP server can speak 1.1 and we can't make any progress.
• It doesn't seem to be headers but merely that broken 1.0 apps look for th string "HTTP/1.0" in order to distinguish it from HTTP/0.9
• Another solution is to change the major version number
• There was no overall consensus

Content-Disposition?

• Give a proposed filename for downloaded files.
• It was considered too late to include a feature like this now. It may be a part of a non-normative appendix
• There is a generic security warning in the equivalent MIME document
• Alex Hopmann volunteered to write up a note about Content Disposition

Warning Headers

• If you have cascaded proxies then warning headers may be cached and passed to the client even though the document has been revalidated and is valid. The rules for how and when to strip warning headers should be made more explicit
• Simon Spero has a pointer

305 Response code Underdefined?

• The current draft does not define 305 probably.
• If you are behind a firewall then a 305 response will fail on all future requests. That is - it has to be a hop by hop and not end to end return code.
• There should be a proxy configuration mechanism so that it can be handled with proxies
•  Ari volunteered to write up a spec about how to use 305. It will probably be a separate spec
• We may want to take it out of the current spec.

Proxy Authentication Underdefined?

• The issuse is that if you have cascaded proxies then the "colapsing" of proxy authentication may fail
• It is a differebt model that originally intended where proxu authentication was a hop-by-hop mexchanism
• Josh Cohen proposed a change to the current draft. He would like to add a realm id. He  committed to send a draft to the mailing list
• This would also have an impact on www-authenticate
• There was overall concensus that we should find out exactly what the changes would have to be
• Available choises: we can make progress within or without HTTP/1.1

Should IMS and IUS be "==" or "<="

• There may be race conditions where a client can get a stale document
• There are also problems in broken client and daylight saving time and clock scew
• There was a certain consencus that an equality check instead of the current less than or equal. It seems to be safer.
• We could recommend that date stamps are not used at all but this will not change existing clients
• Clients may reformat the date/time stamp when revalidating

Who should close the Connection?

• It is not clear at this point in time and we need more implementation experience
• We may want to come up with an implementation advice

Content Negotiation

Transparent Content Negotiation

Overview by Andy Mutz:

• How to handle multiple variants is an important issue in i18n
• How does this interact with proxies and caches
• Having the clients telling its preferences does not scale. Instead the server can ennumerate the chioces
• There are at least two implementations that can interoperate
• Request for moving this to proposed standard in January and hook up to HTTP/1.1? What should we do?
• Implementation problems: charset, MIME types are not orthogonal!
• It is still not clear how useful the current spec is in practice
• It is problematic to specify the algorithm for how to do content negotiation, q values should be relative and not absolute
• It was proposed to isolate the alternate part from the rest of the current spec.
• There are some open issues: Server rendering machanisms?, Quality values on feature tags?

Feature Tag Registration

Overview by Anydu Mutz:

• The current draft needs more comments and work
• Larry committed to make sure that the draft is added to the wg home page

User Agent Display Attributes

• Where should this go? It could be part of a transparent content negotiotaion or it can be part of a feature tage negotiation
• Yaron (MS) referred to the draft issued by MS to describe the feature tags that MS would like to have. It is not a proposal for a core set

Continues tomorrow...

changes since then:

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