1 SOAP : Simple Object Access Protocol Dr. Yuhong Yan NRC-IIT-Fredericton Internet logic.

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SOAP : Simple Object Access Protocol

Dr. Yuhong YanNRC-IIT-Fredericton

Internet logic

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Service Oriented Architecture (SOA)/Web Service triangle

From “Web Services Architecture W3C Working Draft”http://www.w3.org/TR/2002/WD-ws-arch-20021114/

WSDL

UDDI

SOAP

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Web Service Stack

Discovery UDDI

Transport HTTP, SMTP, FTP, BEEP

Description WSDL

XML messaging XML-RPC, SOAP, XML

Process BPEL4WS, WSCI, WS-CDL

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SOAP (Simple Object Access Protocol)

SOAP is a lightweight protocol for exchange of information in a decentralized, distributed environment. It is an XML based protocol that consists of three parts: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined data types, and a convention for representing remote procedure calls and responses.

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Look into a SOAP message

<?xml version="1.0" encoding="UTF-8"?><soapenv:Envelope

xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<soapenv:Body> <ns1:getQuote

soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="urn:xmltoday-delayed-quotes">

<symbol xsi:type="xsd:string">XXX</symbol> </ns1:getQuote> </soapenv:Body></soapenv:Envelope>

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Response SOAP message

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<soapenv:Body> <ns1:getQuoteResponse

soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="urn:xmltoday-delayed-quotes">

<ns1:getQuoteReturn href="#id0"/> </ns1:getQuoteResponse> <multiRef id="id0" soapenc:root="0"

soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xsi:type="xsd:float" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/">55.25</multiRef>

</soapenv:Body></soapenv:Envelope>

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Inside SOAP

P53, figure 3-2

Envelope (required)

SOAP message

Header (optional)

Body (required)

Fault (optional)

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Why SOAP

• Inter-application communication between systems written in arbitrary languages, across the Internet.

• An XML-based protocol for exchanging messages over Internet transport protocols, like HTTP, SMTP, FTP, etc.

• SOAP is platform-independent.

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Apache SOAP architecture

p69,. Fig 4-3

Service:HelloService.java

AXIS SOAP enginerpcrouter servlet

SOAP client: HelloClient.java

Jakarta Tomcat server

SOAP request:Service name: urn:HelloWorldMethod name: sayHelloParameter: firstName=“Yuhong”

lastName=“Yan”SOAP response:

Return value: “Yuhong Yan, welcome to SOAP”

“Yuhong Yan, Welcome to SOAP…”sayHello(“Yuhong”, “Yan”)

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3

4

5Http POST

Http GET

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Anatomy of HelloWorld

• Server side code• Client side code• SOAP request• SOAP response

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HelloWorldService.java

package samples.HelloWorld;

public class HelloWorldService{ public String sayHello(String firstName, String lastName) throws Exception { String aString = firstName + “ " + lastName + ", welcome to SOAP Web Service

World!"; return aString; } public String addString(String symbol, String dataType) throws Exception { String aString = symbol + dataType; return aString; }}

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TestClient

public class TestClient{ public static void main(String args[]) { try { Options opts = new Options( args ); args = opts.getRemainingArgs();

Parse the arg[ ] into options (user,url,etc) and non-options

args.

get non-options args.

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TestClient.java (2)

Service service = new Service();Call call = (Call) service.createCall();call.setTargetEndpointAddress( new

java.net.URL(opts.getURL()) );if( args[0].equals("1") ) call.setOperationName( new

QName("urn:HelloWorld", "sayHello") );else call.setOperationName( new

QName("urn:HelloWorld", "addString") );

The start point of access SOAP web servicesCall invokes SOAP web services

Default URL "http://localhost:8080/axis/servlet/AxisServlet

Or You can use the SOAP endpoint as in WSDL"http://localhost:8080/axis/services/urn:HelloWorld"

Service Name Service Method

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TestClient.java

call.addParameter( “p1", XMLType.XSD_STRING, ParameterMode.IN );

call.addParameter( “p2", XMLType.XSD_STRING, ParameterMode.IN );

call.setReturnType( XMLType.XSD_STRING );

call.setUsername( opts.getUser() );call.setPassword( opts.getPassword() );

Add the parameters for the remote method

Parameter name. Arbitrary. Appear in request SOAP messageXML data type for the para

IN/OUT/INOUT

Security options

Define the return value

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Request SOAP message



<soapenv:Body> <ns1:sayHello

soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="urn:HelloWorld">

<p1 xsi:type="xsd:string">Yuhong</p1> <p2 xsi:type="xsd:string">Yan</p2> </ns1:sayHello> </soapenv:Body></soapenv:Envelope>

Remote method name

Name of the web serviceParameter name.

Parameter type. need to match WSDL. Value of the parameter

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TestClient.java

String res = (String) call.invoke( new Object[] { args[1], args[2] } );

System.out.println( "Return is: " + res ); } catch( Exception e ) { e.printStackTrace(); } } }//end of class

Return value

Invoke the web service

Passing parameters

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Response SOAP message


<soapenv:Body> <ns1:sayHelloResponse


<ns1:sayHelloReturn xsi:type="soapenc:string" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/">Yuhong,Yan, Welcome to SOAP Web Service World!</ns1:sayHelloReturn>

</ns1:sayHelloResponse> </soapenv:Body></soapenv:Envelope>

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Inside SOAP

P53, figure 3-2

Envelope (required)

SOAP message

Header (optional)

Body (required)

Fault (optional)

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Envelope

• The root element of SOAP message• Uses XML namespaces to differentiate versions• Two versions 1.1, 1.2• No third string

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"

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Header (optional)

• For authentication, transaction management, and payment authorization

• Two defined attributes– Actor attribute: the chained node– MustUnderstand attribute: force the recipient

to process the element, if not understandable, return a fault

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Header (optional) (2)

<SOAP-ENV:Header><ns1:PaymentAccount xmlns:ns1=“urn:ecerami”

SOAP-ENV:mustUnderstand=“true”>orsenigo473

</ns1:PaymentAccount></SOAP-ENV:Header>

P54. the soapheader

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Body

• Where the transferred data is• Data encoding via XML Schemas

<soapenv:Body> <ns1:sayHello soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" xmlns:ns1="urn:HelloWorld"> <p1 xsi:type="xsd:string">Yuhong</p1> <p2 xsi:type="xsd:string">Yan</p2> </ns1:sayHello> </soapenv:Body>

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Fault (optional)

• faultCode– SOAP-ENV:VersionMismatch– SOAP-ENV:MustUnderstand– SOAP-ENV:Client (non existing methods)– SOAP-ENV:Server (not able to access DB)

• faultString• faultActor• detail

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Fault (optional)-2

<?xml version=‘1.0’ encoding=‘UTF-8’?><SOAP-ENV:Envelope

xmlns:SOAP-ENV=“http://schemas.xmlsoap.org/soap/envelope/”xmlns:xsi=“http://www.w3.org/1999/XMLSchema-instance”xmlns:xsd=“http://www.s3.org/1999/XMLSchema”><SOAP-ENV:Body>

<SOAP-ENV:Fault><faultcode xsi:type=“xsd:string”>SOAP-ENV:Client</faultcode><faultstring xsi:type=“xsd:string”>

Failed to locate method (ValidateCreditCard) in class(examplesCreditCard) at /usr/local/ActivePerl-5.6/lib/site_perl/5.6.0/SOAP/Lite.pm line 1555.

</faultstring></SOAP-ENV:Fault>

</SOAP-ENV:Body></SOAP-ENV:Envelope>

P55. xml part (for faults)

http://schemas.xmlsoap.org/soap/envelope/



http://www.w3.org/1999/XMLSchema-instance

http://www.s3.org/1999/XMLSchema

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SOAP message inside HTTP message

• SOAP is inside a HTTP message• How client-server talks in HTTP

– The client identifies the server via a URI– connects to it using the underlying TCP/IP

network– issues a HTTP request message (POST)– receives a HTTP response message (GET)

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SOAP request message is within HTTP POST

POST /axis/services/urn:HelloWorld HTTP/1.0Content-Type: text/xml; charset=utf-8Accept: application/soap+xml, application/dime,

multipart/related, text/*User-Agent: Axis/1.2alphaHost: localhost:8080Cache-Control: no-cachePragma: no-cacheSOAPAction: ""Content-Length: 474Authorization: Basic dXNlcjE6cGFzczE=

Here is the HTTP header you see from the log

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SOAP request message is within HTTP POST



<soapenv:Body> <ns1:sayHello


<p1 xsi:type="xsd:string">Yuhong</p1> <p2 xsi:type="xsd:string">Yan</p2> </ns1:sayHello> </soapenv:Body></soapenv:Envelope>

Here is the HTTP body – That is the SOAP message

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SOAP response message is within HTTP GET

This should be in HTTP header

GET /axis/services/urn:HelloWorld HTTP/1.0Content-Type: text/xml; charset=utf-8Accept: application/soap+xml, application/dime,

multipart/related, text/*User-Agent: Axis/1.2alphaHost: localhost:8080……

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SOAP response message is within HTTP GET


<soapenv:Body> <ns1:sayHelloResponse


<ns1:sayHelloReturn xsi:type="soapenc:string" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/">Yuhong,Yan, Welcome to SOAP Web Service World!</ns1:sayHelloReturn>

</ns1:sayHelloResponse> </soapenv:Body></soapenv:Envelope>

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Axis Client

XMLSchema

XMLdata types

SOAP ServerJava Objects

and data types

Client

follows

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Axis client

• Map java data types to XSD data type• Serialize java objects into XML• Send SOAP request to server (not necessarily

Axis server)• Interpret SOAP response

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XML <-> Java Data Mapping in Axis

• Primitives• Beans• User Defined Types (classes)• Code Demo

References:

AXIS User Guide

AXIS sample code

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Primitives: the mapping tablexsd:base64Binary byte[]xsd:boolean booleanxsd:byte bytexsd:dateTime java.util.Calendarxsd:decimal java.math.BigDecimalxsd:double doublexsd:float floatxsd:hexBinary byte[]xsd:int intxsd:integer java.math.BigIntegerxsd:long longxsd:QName javax.xml.namespace.QNamexsd:short shortxsd:string java.lang.String

1 SOAP : Simple Object Access Protocol Dr. Yuhong Yan NRC-IIT-Fredericton Internet logic.

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