Re: [hybi] [Uri-review] ws: and wss: schemes
noah_mendelsohn@us.ibm.com Wed, 19 August 2009 16:21 UTC
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To: Jamie Lokier <jamie@shareable.org>
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Cc: hybi@ietf.org, uri-request@w3.org, Kristof Zelechovski <giecrilj@stegny.2a.pl>, uri@w3.org, uri-review@ietf.org, 'David Booth' <david@dbooth.org>
Subject: Re: [hybi] [Uri-review] ws: and wss: schemes
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Jamie Lokier writes: > A HTTP URL does not tell you the type of resource, only where to > find _a_ resource. This misses an important point about http URIs and the HTTP protocol. Although the URL itself does not tell you the type of the resource, the response to an HTTP GET does indeed tell you the type of the entity body. So, you can access any such URI on the Web, and you'll either: (1) know how to interpret the response, I.e. because you recognize the Content-type and know how to process data of that type, or (2) will reliably discover that it's of a type you don't know how to process. These characteristics are what make it possible for you to click on any link, and know that your browser won't misinterpret the results, even as new Content-types are deployed (well, let's not get into the sniffing discussion just now). It's also what allows search engine spiders to interpret the results returned from GETs on pretty much any http link. So, this is a desirable characteristic for Web resources, and it's one of the things that HTTP gives you. Indeed, the whole Web is designed so that you can start with RFC 3986, the specification for URIs, and using the references to which it (recursively) delegates, discover how to correctly interact with and interpret responses from any resource on the Web. Under the auspices of the W3C TAG, I prepared a "finding" [1] that goes into more detail on these issues and their implications. BTW: the above comment is not intended to express an opinion about the proposed ws/wss URI schemes; it's a reaction to Jamie's comment. I do think it is an interesting question (I think I've raised it before), whether we expect search engines to come on ws/wss links, and if so, whether it's valuable for those search engines to be able to discover information about the resources identified by those links. Noah [1] http://www.w3.org/2001/tag/doc/selfDescribingDocuments.html -------------------------------------- Noah Mendelsohn IBM Corporation One Rogers Street Cambridge, MA 02142 1-617-693-4036 -------------------------------------- Jamie Lokier <jamie@shareable.org> Sent by: uri-request@w3.org 08/14/2009 05:37 PM To: Kristof Zelechovski <giecrilj@stegny.2a.pl> cc: "'David Booth'" <david@dbooth.org>, "'Ian Hickson'" <ian@hixie.ch>, uri-review@ietf.org, hybi@ietf.org, uri@w3.org, (bcc: Noah Mendelsohn/Cambridge/IBM) Subject: Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski wrote: > 1. Encouraging the user to enter a Web Sockets URL does not make sense if > cross-domain connections are not allowed, which I hope will be the case (the > draft specification [1] does not contain security considerations). It was originally thought XHR (XmlHttpRequest) didn't need to be cross-domain, but then people thought of lots of reasons why it's useful and had to use hacks to workaround the limitation, so now there's a draft standard to support cross-domain XHR - being careful to address cross-domain security. I suspect WebSockets could benefit from a look at the mechanisms used by cross-domain XHR to check for permission to proceed. > 2. While we are at it, a Web Sockets connection is useless without knowing > the protocol, and the protocol to be used is not contained within the URL. > That means a ws URL is not self-contained and thus useless as a stand-alone > locator. The same is true of HTTP. A HTTP URL does not tell you the type of resource, only where to find _a_ resource. For example there are places where a user can enter the URL of a CalDAV calendar resource. The CalDAV protocol is used (over HTTP) to work with that resource, but the URL doesn't say what it is. The only difference with WebSockets is that it (so far) seems to avoid any descriptive metadata, which means there will still be applications which ask for a WebSockets URL, but when the URL is for a different protocol on top, it'll simply break with undefined behaviour instead of a clean error message or fallback behaviour. It doesn't matter if you think nobody should do that. It will still be done anyway - because it's so obviously useful. -- Jamie
- [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Greg Wilkins
- Re: [hybi] [Uri-review] ws: and wss: schemes Ian Hickson
- Re: [hybi] [Uri-review] ws: and wss: schemes Maciej Stachowiak
- Re: [hybi] [Uri-review] ws: and wss: schemes Chris Anderson
- Re: [hybi] [Uri-review] ws: and wss: schemes Mark Nottingham
- Re: [hybi] [Uri-review] ws: and wss: schemes Pieter Hintjens
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Greg Wilkins
- Re: [hybi] [Uri-review] ws: and wss: schemes Maciej Stachowiak
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Maciej Stachowiak
- Re: [hybi] [Uri-review] ws: and wss: schemes Maciej Stachowiak
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes David Orchard
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Ian Hickson
- Re: [hybi] [Uri-review] ws: and wss: schemes Roy T. Fielding
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Ian Hickson
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes noah_mendelsohn
- Re: [hybi] [Uri-review] ws: and wss: schemes Toby Inkster
- Re: [hybi] [Uri-review] ws: and wss: schemes Křištof Želechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Erik Wilde
- Re: [hybi] [Uri-review] ws: and wss: schemes noah_mendelsohn
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes John Kemp
- Re: [hybi] [Uri-review] ws: and wss: schemes noah_mendelsohn
- Re: [hybi] [Uri-review] ws: and wss: schemes Mark Nottingham
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Erik Wilde
- Re: [hybi] [Uri-review] ws: and wss: schemes noah_mendelsohn
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes noah_mendelsohn
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Toby Inkster
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] ws: and wss: schemes Martin J. Dürst
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Toby Inkster
- Re: [hybi] [Uri-review] ws: and wss: schemes David Booth
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Martin J. Dürst
- Re: [hybi] [Uri-review] ws: and wss: schemes Křištof Želechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Křištof Želechovski
- Re: [hybi] [Uri-review] ws: and wss: schemes Jamie Lokier
- Re: [hybi] [Uri-review] ws: and wss: schemes Joseph A Holsten
- Re: [hybi] [Uri-review] ws: and wss: schemes Joseph A Holsten
- Re: [hybi] [Uri-review] ws: and wss: schemes Joseph A Holsten
- Re: [hybi] [Uri-review] ws: and wss: schemes Daniel R. Tobias
- Re: [hybi] [Uri-review] ws: and wss: schemes Daniel R. Tobias
- Re: [hybi] [Uri-review] ws: and wss: schemes Daniel R. Tobias
- Re: [hybi] [Uri-review] ws: and wss: schemes Lisa Dusseault
- Re: [hybi] [Uri-review] ws: and wss: schemes Infinity Linden
- Re: [hybi] [Uri-review] ws: and wss: schemes Lloyd Wood
- Re: [hybi] [Uri-review] ws: and wss: schemes Kristof Zelechovski
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Ian Hickson
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] ws: and wss: schemes Roy T. Fielding
- Re: [hybi] ws: and wss: schemes Julian Reschke
- Re: [hybi] [Uri-review] ws: and wss: schemes Martin J. Dürst
- Re: [hybi] ws: and wss: schemes Ian Hickson