[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Web Service: SOAP or {HTML + Servlets}?
If your application is better modeled in a document-centric way, you will do well to stick to that model, & not worry about SOAP. Some applications are simply not modeled this way, & *need* "remote API calls". Even there, my own preference has always been to use a HTML form to send "API call arguments", & my own format to receive the results. Biggest drawback of SOAP is I need to write a client before I can begin to test my server; with HTML form based stuff, I can test these things from browser. I am open to be convinced that third-party toolkits for SOAP are a help - I find them more work then they are worth. What is the value they are giving? Envelop parsing - must be < 0.01% of any non-trivial application! And you are *forced* to use XML Schema. Or have I missed something central? -----Original Message----- From: Roger L. Costello [mailto:costello@m...] Sent: Wednesday, October 10, 2001 2:47 AM To: xml-dev@l... Subject: Web Service: SOAP or {HTML + Servlets}? Hi Folks, I have been looking at SOAP recently. Although its great fun to play with new technologies, I am struggling to see why I should recommend to my clients that they use SOAP rather than, say, HTML plus Java Servlets (or CGI, JSP, ASP, etc) to implement Web Services. Here are a couple of thoughts: 1. SOAP -> API-based architecture HTML + Servlets -> Document-based architecture SOAP is about enabling one application to invoke a method in another application by passing arguments. It's basically about enabling a (remote) subroutine call. Hidden behind the scenes is the construction of a SOAP XML document, and the passing of that XML document. From a document-based architecture point of view, the fact that the transport is an XML document is immaterial. Contrast this with the HTML + Servlet technology where an application creates an HTML document, which is sent to an application (servlet) for processing. This is a document-based architecture. I am dismayed that SOAP has gone the API-based architecture approach. I would have thought that the progression would be from HTML + Servlets (or CGI, JSP, ASP, etc) to XML + Servlets (or CGI, JSP, ASP, etc) A long time ago I saw the enormous benefits of document-based architectures. I switched from using API-based architectures to document-based architectures. I am extremely reluctant to regress back to an API-based framework. 2. SOAP provides a (very) loose framework for sending data/requests to a server. Basically, it leaves a bunch of "empty space" in the framework where you can put stuff: <Envelope> <Header> - put anything here </Header> <Body> - put anything here </Body> </Envelope> That's about the extent of the semantics of SOAP. Presumably, each vendor must define what elements can go in the Header element, and the semantics of those elements. Not a very attractive prospect from a cross-vendor point of view. On the other hand, if I were to implement Web Services using HTML + Servlets then the semantics of all the HTML elements are concretely defined. There is rich (standard, non-vendor-specific) support for things such as HTTP sessions, authentication, security, etc. None of this exists with SOAP. My vision of next generation Web Services is an XML-document-based architecture, with a well-defined set of elements. I envision the XML documents conforming to an XML Schema. I envision schema validation of the documents. I don't see any of this in SOAP. I'd like to use SOAP for implementing Web Services. It seems to be a fun technology to play with. But, in good conscience, I am real hard pressed to see any advantage to it over HTML plus Servlets (or XML plus Servlets). I am eager to be convinced otherwise, however. What are your thoughts on this? /Roger ----------------------------------------------------------------- The xml-dev list is sponsored by XML.org <http://www.xml.org>, an initiative of OASIS <http://www.oasis-open.org> The list archives are at http://lists.xml.org/archives/xml-dev/ To subscribe or unsubscribe from this elist use the subscription manager: <http://lists.xml.org/ob/adm.pl>
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