Hi Steve! > Note that there's no standard way of doing this in WS either.
True but there at least have been several attempts: ADS (Advertisement and Discovery of Services), WS-Discovery, WSIL (Web Services Inspection Language), and of course WS-MetadataExchange. The last is not a discovery protocol as much as it is a way to get metadata once you know the endpoint of a service. In the REST space none of this stuff existed because REST has been used for human driven apps where its not needed .. google works just fine. When ADS and WSIL was designed the idea was that it would enable a Google to crawl around and discover services .. I still think the idea is sound but the time hasn't yet come for it. > One generally writes a WSDL to describe a WS-style web service, but > how do clients get that WSDL? Is there a standard for publishing > those WSDLs and allowing clients to retrieve them? You might say > UDDI, but only a few actually use that. Fact is, there is no widely- > used WS registry or naming service standard. Some kits support > tacking "?wsdl" onto the service URL to retrieve its WSDL, but unless > I've missed a new standard along the way, that's only a convention, > and again, only some kits support it (and it also requires a live > service). > > So, Steve, when you write a WS-style web service, how *do* your > clients get the information they need to be able to properly call > your service? Do you post the WSDL on a web page where clients > retrieve it, or do you use the ?wsdl convention, or do you write a > Word doc and email it to your colleagues, or do you use UDDI or maybe > a vendor-specific or homegrown registry, or perhaps you use yet > another approach that I haven't mentioned? You have to agree that at least in WS-* land there exists WSDL and a bunch of efforts to solve the discovery problem. In REST land until recently restafarians said "ah WSDL-like ugly static binding mechanisms are not needed; we're so hang loose types" but have now finally come to the realization that it is needed: Enter WADL, URI templates etc. .. but without being standards, who cares? WSDL 2.0's HTTP binding has (IMO) the 80-20 needed to make plain HTTP (I'm avoiding using the R-term) really describable and usable by programming tools in addition to humans but restafarians don't like it because it doesn't start by naming operations GET/POST/etc.. Oh well. Sanjiva. -- Sanjiva Weerawarana, Ph.D. Founder & Director; Lanka Software Foundation; http://www.opensource.lk/ Founder, Chairman & CEO; WSO2, Inc.; http://www.wso2.com/ Director; Open Source Initiative; http://www.opensource.org/ Member; Apache Software Foundation; http://www.apache.org/ Visiting Lecturer; University of Moratuwa; http://www.cse.mrt.ac.lk/
