XML and SOAP Examples

1
XML and SOAP Examples
CERN April 1 2003 Grid Tutorial

• PTLIU Laboratory for Community Grids
• Geoffrey Fox, Marlon Pierce
• Computer Science, Informatics, Physics
• Indiana University, Bloomington IN 47404

gcf_at_indiana.edu
2
A Sample of XML

• lt?xml version"1.0"?gt
• ltokc version"3" xmlns"http//grids.ucs.indiana.e
  du/okc/schema/admin/ver/3"gt
• lteventgt
• ltcommentgt This is a Test lt/commentgt
• ltsender email"gcf_at_grids.ucs.indiana.edu"gt
  Geoffrey Foxlt/sendergt
• ltdistributiongt Community Grids Project
  Reports lt/distributiongt
• ltorganizationgtlt/organizationgt
• ltupdate createuri"gxos//okc/newsgroups/c
  greports/next /gt
• ltkeywordsgtlt/keywordsgt
• ltsubjectgtlt/subjectgt
• ltmessage/gt
• ltfilingdategt 2/6/2002 lt/filingdategt
• ltcgmessageType xmlnscghttp//grids.ucs
  .indiana.edu/okc/schema/cg/ver/1 gt
• Test lt/cgmessageTypegt
• lt/eventgt
• lt/okcgt

Schema are here
http//grids.ucs.indiana.edu/schemas/commgrids-v1.
xsdhttp//grids.ucs.indiana.edu/schemas/okc-v3.xs
d
3
SOAP over HTTP Structure

• SOAP defines a message with envelope, header and
  body
• The SOAP standard also defines a binding to HTTP
  which is equivalent to methodology for delivering
  message
• The SOAP body can specify data as well as fault
  processing information
• SOAP can be transported over standard mail by
  just putting XML in body of mail see

http//xml.apache.org/soap/faq/faq_chawke_smtp.htm
l http//www.w3c.org/2000/xp/Group/1/11/16/soap12-
primer.htmlSMTP
4
SOAP Example from W3C I

• We take November 16 tutorialhttp//www.w3c.org/2
  000/xp/Group/1/11/16/soap12-primer.html
• This is a SOAP Message defining a reservation
  request
• Header has key meta-data of application (namelist
  m and instructions to SOAP (intermediate actor)
  processors

Start Envelope
Start Header
End HeaderStart Body
5
SOAP Example (Concluded)
Start Body

• This has the SOAP Body with actual request

End BodyEnd Envelope
6
SOAP Binding to SMTPfrom W3C

• Same example as before
• This is very straightforward!

7
Remarks on SOAP Structure

• If you look at networking protocols, at each
  layer one specifies a header and a body
• HTTP has a header telling system where to send
  information and some high level specification of
  what to get
• In example, we see that body of HTTP message is
  full SOAP envelope and this envelope has SOAP
  Header and Body interpreted by application
• At a lower level in protocol stack, TCP/IP and
  ATM etc. have their own headers and bodies
• It is the standard Russian Doll situation each
  doll has a body (contained inside it) which is
  the full doll of higher level protocol

HTTP
SOAP
SOAP Body
8
SOAP Attachments

• This uses same approach as email or HTTP and is a
  general way of including binary data in XML but
  not understood by most parsers!
• Very important?

XML links to MIMEAttachment using absolute or
relative URIs
9
SOAP and Gateway Portal I

• Having specified service in WSDL, the run-time is
  implemented in SOAP which is just an XML header
  (info needed by transport empty here) and body
• Here is SOAP transported by HTTP message
• This is execLocalCommand WSDL operation to run
  one particular command (ls) on current WebFlow
  directory

HTTP Header
Argument of operation
Specify ls as
SOAP Envelope and body
10
SOAP and Gateway Portal II
HTTP Header
SOAPEnvelopeand body

• And this is the result of ls sent back to client
  in SOAP over HTTP

11
WSDL Definitions and Namespaces

• lt?xml version"1.0" encoding"UTF-8" ?gt
• ltdefinitions name"BatchScriptService"
• targetNamespace"http//yourserver/BatchScriptSer
  vice"
• xmlns"http//schemas.xmlsoap.org/wsdl/"
• xmlnssoap"http//schemas.xmlsoap.org/wsdl/soap/
  "
• xmlnstns"http//yourserver/BatchScriptServi
  ce"
• xmlnsxsd"http//www.w3.org/1999/XMLSchema
  gt

Default Schema (null namespace) is WSDLsoap
namespace is SOAP binding of WSDLtns namespace
is this WSDL file xsd namespace defines (ancient)
XML Schema
12
WSDL Message Example
ltmessage name"submitRequest"gt ltpart
name"xmljob" type"xsdstring"/gt lt/messagegt ltmess
age name"submitResponse"gt ltpart
name"response" type"xsdstring"/gt lt/messagegt
For the batch script service, we pass the XML
description of the job as a string and get back
the script as a string. In general, any XML
primitive or complex types can be used in
messages. We could improve our service by
defining a BatchScript complex type.
13
WSDL portTypes Example
ltportType name"BatchScriptServicePortType"gt
ltoperation name"batchGen"gt ltoutput
message"tnssubmitResponse" name"submitRespon
se"/gt ltinput message"tnssubmitRequest"
name"submitRequest"/gt lt/operationgt
lt/portTypegt
A portType corresponds to a Java class, so if we
compile this WSDL to make client stubs, we will
generate a BatchScriptServiceBinding.java class.
14
WSDL SOAP Binding Example
ltbinding name"BatchBinding" type"tnsBatchScript
ServicePortType"gt ltsoapbinding style"rpc"
transport"http//schemas.xmlsoap.org/soap/http"/
gt ltoperation name"batchGen"gt
ltsoapoperation soapAction""/gt ltinputgt
ltsoapbody use"encoded
namespace"urnBatchScriptService"
encodingStyle"http//schemas.xmlso
ap.org/soap/encoding/"/gt lt/inputgt
ltoutputgt ltsoapbody use"encoded"
namespace"urnBatchScriptService encodingStyle
"http//schemas.xmlsoap.org/soap/encoding/"/gt
lt/outputgt lt/operationgt lt/bindinggt
note bindings type attribute points back to
the portType tag by name
15
WSDL Ports and Services
ltservice name"BatchScriptService"gt
ltdocumentationgtBS stands for Batch Script
lt/documentationgt ltport binding"BatchBinding
name"BatchPort"gt ltsoapaddress
location "http//yourserver/soap/servlet/rpcrout
er/"/gt lt/portgt lt/servicegt lt/definitionsgt
ports are concrete implementations of portTypes
and point back to a particular binding (by name).
They also point to the specific location of a
server that implements the service. A service is
a collection of one or more ports.