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The World Wide Web is more and more used for application to application com-
munication. The programmatic inter-
faces made available are referred to as Web services.
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Providing access using WebServices makes it possible to use the tools from other sites automatically and compute results remotely without detailed technical knowledge of the tool.
The underlying protocol SOAP is defined by the W3C and uses http as transport protocol. Communication to and from WebServices is performed in XML. A WebService is described in a so called WSDL document ( WebService Description Language), it includes all required information for connecting the WebService, like the location of the WebService and the interface description. Distributing these WSDL documents makes it possible to connect WebServices using SOAP implementations, which are available for all current programming languages like Java, Perl, PHP, C and C++.
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Although a lot of middleware technologies are currently available, many of them don't fit recent demands.
Some of them require commercial software (eg. TUXEDO) which is definitely an exclusion criteria. Others like J2EE are implementable with Open Source software but they are language dependant. Another issue are problems with the data format and/or the used protocols.
CORBA for example is language independant but operates with the binary IIOP protocol, which causes problems behind firewalls.
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If you are working from within the GZI, i.e. the TechFak net, you have to set the HTTP_proxy environment variable to http://www-proxy.techfak.uni-bielefeld.de:80.
The best way to do so, is by including the line
export HTTP_proxy=http://www-proxy.techfak.uni-bielefeld.de:80
at the end of your .bashrc file.
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