Thanks Willy, you made my point better than I did. It is my opinion that name resolution (however done) is outside the purview of WS. It may be handled in any number of ways by the client, and must happen *before* WS establishes it's TCP connection and begins handshaking.
DNS, DNS SRV, etc. are good and useful tools, but are not part of WS. A document showing how to use DNS SRV with WS would be useful, but it's not part of the core WS spec. On Thu, Jul 21, 2011 at 12:39 PM, Willy Tarreau <w...@1wt.eu> wrote: > On Thu, Jul 21, 2011 at 06:27:49PM +0200, Iñaki Baz Castillo wrote: > > 2011/7/21 David Endicott <dendic...@gmail.com>: > > > DNS resolution is not a function of a transport protocol. DNS SRV has > no > > > special association with WS. It is my opinion that this would be > > > additional cruft that is only marginally related to the purpose and > function > > > of websockets. It does not address a general use case. DNS SRV > applies > > > only to a (small?) subset of server-side implementations. It is a > good > > > and useful mechanism, but I do not believe it should be tied tightly to > > > websockets, nor included as part of the core spec. > > > > An WebSocket URI is given to a WebSocket client, and the client MUST > > locate the corresponding WS server, right? and for locating the server > > the client MUST follows a procedures which, for now, involve (if it's > > not an IP) DNS A/AAAA resolution, right? So now imagine that the > > location mechanism is a bit more powerful and also involves SRV > > queries (not always). > > > > If you think that a transport protocol (like WebSocket) must not > > resolve a server destination then also remove the WS URI inspection > > and resolution from the core spec, don't you agree? or just DNS A/AAA > > is valid? > > > > I don't agree with your opinion at all. Regards. > > Iñaki, > > I understand the point David is making. DNS is something independant of > WS and conversely. It is one way of resolving addresses, just like there > will be people using hosts files. At no place the protocol specification > dictates how a client should resolve a name to an IP address. The protocol > specifies the transport part only. > > This is the same for other protocols. For instance, neither FTP nor HTTP > explain how a client is supposed to resolve a host name, still the later > explains how to parse a URI. DNS SRV is a DNS extension which only concerns > resolvers. Not all clients will be using resolvers, just a part of them. > Some others will simply forward the request to their HTTP proxy which will > apply whatever DNS resolving method they know, including possibly DNS SRV. > > In practice, if there are new elements of DNS SRV that are specific to WS, > they should probably be added to the DNS SRV spec and not the WS spec. > Maybe the WS spec should mention that it addresses transport only and > not address resolving. It may recommend to follow some principles to > perform the resolving but should not specify how to do it. > > Hoping it's a bit clearer, > Willy > >
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