SOAP: Difference between revisions
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'''SOAP''' is a [[XML]]-based protocol for exchanging data over a network. It used to stand for ''Simple Object Access Protocol''. | '''[http://www.w3.org/TR/soap/ SOAP]''' is a [[XML]]-based protocol for exchanging data over a network. It used to stand for ''Simple Object Access Protocol'', but since it was not all that simple and not in any meaningful way [http://en.wikipedia.org/wiki/Object-oriented_programming object oriented] it has been, by consensus, retrospectively stripped of its acronym status. It is often proposed that it should now stand for ''Service Oriented Architecture Protocol'', however this is only a little better, as [[SOA|Service Oriented Architectures]] require many other protocols than SOAP, and indeed can be built entirely without it. | ||
SOAP is the basis of [[Web Service|Web Services]] within [[Visual DataFlex]]. | SOAP is the basis of [[Web Service|Web Services]] within [[Visual DataFlex]]. | ||
A SOAP message is composed of an outer element, the '''Envelope''', which then contains an optional '''Header''' element and a required '''Body''' element. Many simple SOAP services make no use of the Header element, but it is required for most of the more advanced [[Web_Services#Web_Service_Protocols|web service protocols]]. | |||
An example of a SOAP message might be (from [http://www.w3.org/TR/2007/REC-soap12-part1-20070427/#firstexample]): | |||
<env:Envelope xmlns:env="<nowiki>http://www.w3.org/2003/05/soap-envelope</nowiki>"> | |||
<env:Header> | |||
<n:alertcontrol xmlns:n="<nowiki>http://example.org/alertcontrol</nowiki>"> | |||
<n:priority>1</n:priority> | |||
<n:expires>2001-06-22T14:00:00-05:00</n:expires> | |||
</n:alertcontrol> | |||
</env:Header> | |||
<env:Body> | |||
<m:alert xmlns:m="<nowiki>http://example.org/alert</nowiki>"> | |||
<m:msg>Pick up Mary at school at 2pm</m:msg> | |||
</m:alert> | |||
</env:Body> | |||
</env:Envelope> | |||
In addition to the three elements mentioned above, SOAP defines a '''Fault''' element, which will appear within the response Body, with additional sub-elements, for returning failure information from the server (from [http://www.w3.org/TR/2007/REC-soap12-part1-20070427/#faultcodes]): | |||
<env:Envelope xmlns:env="<nowiki>http://www.w3.org/2003/05/soap-envelope</nowiki>" | |||
xmlns:m="<nowiki>http://www.example.org/timeouts</nowiki>" | |||
xmlns:xml="<nowiki>http://www.w3.org/XML/1998/namespace</nowiki>"> | |||
<env:Body> | |||
<env:Fault> | |||
<env:Code> | |||
<env:Value>env:Sender</env:Value> | |||
<env:Subcode> | |||
<env:Value>m:MessageTimeout</env:Value> | |||
</env:Subcode> | |||
</env:Code> | |||
<env:Reason> | |||
<env:Text xml:lang="en">Sender Timeout</env:Text> | |||
</env:Reason> | |||
<env:Detail> | |||
<m:MaxTime>P5M</m:MaxTime> | |||
</env:Detail> | |||
</env:Fault> | |||
</env:Body> | |||
</env:Envelope> | |||
[[Category:Web Services]] | [[Category:Web Services]] | ||
