Web Service Overview

Function

� Function คือ โปรแกรมยอ่ยชนิดหนึ�ง ซึ�งอาจจะมีการรับคา่มาจากโปรแกรมหลกัที�เรียกใช้ Function นั (นๆ จากนั (นจะมีการประมวลผลคําสั�งใน Function พร้อมกบัจะมีการคืนคา่กลบัไปที�โปรแกรมหลกัที�เรียกใช้งาน Function นั (นๆ

Function cal (number As Integer) Dim result As Integerresult = number ** 2return resultEnd Function

…Call function cal(2)

importing result.write result.…

Function

Main Program 1

…Call function cal(4)

importing result.write result.…

Main Program 2

Web Application

3.Web Service

2.Dynamic

1.Static

HTTP request

Web Application ยุคที& 1 : Static Web Page

Web Browser Web Server

http://www.prapoj.com/current.html

Web Pages

HTTP response

HTTP response

Web Application ยุคที& 2 : Dynamic Web Page

Data

Web Server

Database

SQL Statement

http://www.prapoj.com/index.asp

Web Browser

.asp,.jsp,.php,.pl…

Web Pages

HTTP request

Web Server

Web Application ยุคที& 3 : Web Service Technology

http://www.prapoj.com/index.aspx

Web Browser

.asp,.php,.pl,jsp… Web Service

Web Service

HTTP requestSOAP over HTTP request

HTTP response

SOAP over HTTP request

Web Server

Web Server

Distributed Computing

JavaWorld

Programming World!

MicrosoftWorld

Distributed Computing

.dll

ASP

VBC#

.NET

C++

EJB

Java

Java

Java

Java Java

Java

Web Service

.dll

ASP

VBC#

.NET

C++

EJB

Java

Java

Java

Java Java

Java

Web ServiceWeb Service

WSDLWSDL

What is Web Service?

Web Service?

� Application หรือโปรแกรม(หรือ Function)ซึ�งทําหน้าที�อยา่งใดอยา่งหนึ�งในลกัษณะให้บริการ(Service) โดยจะถกูเรียกใช้งานจาก Application หรือโปรแกรมอื�นๆผา่นทาง Web (Web Server โดยอาศยั SOAP Protocol) การให้บริการของ Web Service นั (น จะมีเอกสารที�อธิบายคณุสมบตัขิองบริการกํากบัไว้(WSDL) และมีการนําเสนอให้สาธารณชนรับทราบ(UDDI) ผู้ ใช้บริการจงึสามารถที�จะค้นหาบริการของ Web Service ตา่งๆได้โดยไมจ่ําเป็นต้องรู้ที�อยู่จริงของ Application หรือโปรแกรมที�ให้บริการ Web Service นั (นๆ

Web Service Definition� Web services are the fundamental building blocks in the move to distributed

computing on the Internet� Open standards and the focus on communication and collaboration among

people and applications have created an environment where XML Web Service are becoming the platform for application Integration

� Applications are constructed using multiple XML Web Services from various sources that work together regardless of where they reside or how they were implemented

� One of the primary advantages of the XML Web Services architecture is that it allows programs written in different languages on different platforms to communicate with each other in a standards-based way

Web Service Concept

Component

Web Service

1

WSDL

Web Server

3

2

WSDL

“Web Services are self-contained, self-describing modular applications that

can be published, discovered and invoked across the Web”

4 SOAP Request

SOAP Response

5

� สร้าง Web Service โดยการพฒันาแบบ Manual หรือใช้เครื�องมือ (Tool) ในการ Generate เราจะได้เอกสาร WSDL บรรยายคณุลกัษณะของ Web Service นั (นๆ

� ทําการ Publish ในสว่นของ Web Service ไปที� UDDI เพื�อให้บคุคลทั�วไปสามารถค้นหา Web Service ที�เราพฒันาขึ (นมาได้

ขั :นตอนในการพัฒนา Web Service

� ค้นหาบริการ Web Service ผา่น UDDI ซึ�งทําให้เราได้ข้อมลูเกี�ยวกบัประเภทบริการ ที�ตั (งของบริการ และเอกสาร WSDL บรรยายคณุลกัษณะของบริการนั (นๆ

� ตดิตอ่ขอใช้บริการ Web Service โดยใช้ SOAP Protocol (SOAP Request)ด้วยการเขียนโปรแกรมขึ (นมาเรียกใช้ Method ของ Web Service นั (นๆโดยอาศยัข้อมลูที�อยูใ่นเอกสาร WSDL

� ผู้ให้บริการสง่ผลลพัธ์กลบัมาในรูปของ XML(SOAP Response)

ขั :นตอนในการเรียกใช้ Web Service

Standards Behind Web services

� Simple Object Access Protocol (SOAP) is based on XML and Hypertext Transport Protocol. It provides a way for applications —including those running on different operating systems — to communicate and work together through remote procedure calls implemented via HTTP

� Universal Description, Discovery and Integration (UDDI) describes how to publish and discover information about Web services applications. It is a Web-based directory where someone can search for particular Web services and what they do

Standards Behind Web services� Web Services Description Language (WSDL), based on XML,

describes the kinds of software applications, or services, available on a particular network. Once someone develops a Web service, they can publish its description and link in a special UDDI repository. When someone wants to use the service, they request the WSDL file so they can determine its location, function calls and how to get to them. They use that information to construct a SOAP request to aserver

� eXtensible Markup Language is a streamlined version of Standard Generalized Markup Language, developed by the International Organization for Standardization to define the structures of different types of electronic documents. XML can be used to store any kind of structured language and encapsulate data so it can be shared between otherwise incompatible computer systems

Web Service Components

Web Service = WSDL + UDDI + SOAP

UDDI Business Registry

Search

Consume

Publis

h

Web Service

WSDLSOAP

UDDI

� Web Service Description Language เป็นภาษาที�ใช้อธิบายคณุลกัษณะของ Web Service และวิธีในการตดิตอ่กบั Web Service โดยใช้ไวยากรณ์ของภาษา XML

WSDL

� WSDL can be used to describe several primary qualities of a Web Service message:� The address Location of WSDL

� The Web Service name

� The Operation(Function/Method) name

� The Input/Output parameters

� The type of data being sent between client and server during a Web Service message exchange

WSDL

1

2

3

4

5

WSDL

� WSDL is used to describe Web Services, client and users of Web Services will use the service descriptions in WSDL to create client proxies that access the service of the provider

� The provider defines the operations, the binding, and the endpoints all in the WSDL document

WSDL

� WSDL stands for Web Services Description Language.

� WSDL is a document written in XML. The document describes a Web service. It specifies the location of the service and the operations (or methods) the service exposes.

WSDL

� The main structure of a WSDL document looks like this:

WSDL Ports� The <portType> element is the most important WSDL

element. � It describes a web service, the operations that can be

performed, and the messages that are involved.� The <portType> element can be compared to a function

library (or a module, or a class) in a traditional programming language.

WSDL Messages� The <message> element defines the data elements of an

operation.

� Each message can consist of one or more parts. The parts can be compared to the parameters of a function call in a traditional programming language.

portType and message Example

WSDL Types� The <types> element defines the data type that are used by the

web service.

� For maximum platform neutrality, WSDL uses XML Schema syntax to define data types.

� Universal Description, Discovery and Integration � http://www.ibm.com/services/uddi/testregistry/find

� http://uddi.microsoft.com/search.aspx

� http://uddi.sap.com

� http://www.xmethods.net/

� http://www.webservicex.net

UDDI

UDDI Example : XMETHODS

www.webservicex.net

� Simple Object Access Protocol เป็น Protocol ที�ใช้ในการเข้าถงึ Object หรือ Component อยา่งง่ายๆ

� SOAP เป็น Protocol ที�อาศยัไวยากรณ์ของภาษา XML

SOAP

SOAP

� SOAP supports distributed computing with XML by providing an effective mechanism for exchanging messages and accessing remote objects via XML

SOAP Message ExampleSOAP Request

SOAP Response

� VB component

� using SOAP toolkit 3.0 to Generate Web Service

� Call Web Service from any client (Programs) � Perl

� Java

Creating Web Service using Tool

� VB component MyAddProj.vbp

� Generate component -> MyAdd.dll

Creating COM Component using VB

Public Function Add(ByVal Num1 as Integer,ByVal Num2 as Integer) As IntegerAdd = Num1 + Num2

End Function

Register component

� Using SOAP Toolkit From Microsoft� Download at http://msdn.microsoft.com

� MyAdd.dll -> � plus2num.wsdl(WSDL file)

Generate Web Service from COM Component

SOAP Toolkit 3.0 WSDL Generator

<?xml version='1.0' encoding='UTF-8' ?>...

<message name='MyAdd.Add'><part name='Num1' type='xsd:short'/><part name='Num2' type='xsd:short'/>

</message><message name='MyAdd.AddResponse'>

<part name='Result' type='xsd:short'/></message>

...<operation name='Add' >...<service name=‘MyAddWS' >...<soap:address location='http://161.200.70.44/myaddws.asp' />

WSDL File (MyAddWS.wsdl)

Web Service name

Operation name

Web Service location

Input Parameter

Output Parameter

http://161.200.70.44/MyAddWS.wsdl

#!c:\perl\bin\perl.exeuse SOAP::Lite;use CGI;$obj = new CGI;$a = $obj->param(number1);$b = $obj->param(number2);print "Content-type:text/html\n\n";$strWSDL = "http://161.200.70.44/myaddws.asp";

print "Result from SOAP Server:</h4>";print "Answer --> ";

print SOAP::Lite-> service($strWSDL) -> Add($a,$b);

Perl Client

import java.io.*;import java.util.*;import java.net.*;import org.w3c.dom.*;import org.apache.soap.util.xml.*;import org.apache.soap.*;import org.apache.soap.encoding.*;import org.apache.soap.encoding.soapenc.*;import org.apache.soap.rpc.*;import org.apache.soap.transport.http.SOAPHTTPConnection;public class testSoapResponse {public static void main(String[] args) throws Exception {URL url = new URL ("http://161.200.70.44/myaddws.asp");SOAPMappingRegistry smr = new SOAPMappingRegistry ();StringDeserializer sd = new StringDeserializer ();smr.mapTypes (Constants.NS_URI_SOAP_ENC,

new QName ("", "Result"), null, null, sd);

Java Client

call.setTargetObjectURI ("http://tempuri.org/message/");call.setMethodName("Add");call.setEncodingStyleURI ("http://schemas.xmlsoap.org/soap/encoding/");Vector params = new Vector();params.addElement(new Parameter("Num1", Double.class,num1, null));params.addElement(new Parameter("Num2", Double.class,num2, null));call.setParams(params);Response resp = null;

try {resp = call.invoke (url, "http://161.200.70.44/MyAddWS.wsdl");

} …

Parameter ret = resp.getReturnValue();Object value = ret.getValue();System.out.println("\n\n Result from SOAP Server : \n\n");System.out.println ("Answer --> " + value);…

Java Client (Continue)