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7/29/2019 XML Presentation

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WEB SERVICES ANDXML BASICS

Author: Sonali Patil



Agenda

Web Services Web Services Architecture

SOAP

UDDI

WSDL WSDL UDDI Relationship

XML XML Tree

XML Syntax Rules

XML DTD

Namespaces

CSS

XSL

XSLT



What are Web Services?

Web services is a piece of software that allow your

application to publish its function or message to the rest

of the world

The basic Web services platform is XML + HTTP.

Is available over the Internet or private (intranet)

networks

Uses a standardized XML messaging system Is not tied to any one operating system or programming

language

Is self-describing via a common XML grammar

Is discoverable via a simple find mechanism



Web Services Architecture

Web Service Roles

Service provider

Service requestor Service registry

Web Service Protocol Stack

Service transport (HTTP) XML messaging (SOAP)

Service description (WSDL)

Service discovery (UDDI)



What is SOAP?

SOAP stands for Simple Object Access Protocol

SOAP is an XML-based protocol to let

applications exchange information over HTTP.

SOAP is a format for sending messages

Show the env,header,body format

SOAP is platform independent

SOAP is based on XML

SOAP allows you to get around firewalls



What is WSDL?

WSDL is used to describe the Web services.

WSDL stands for Web Services Description Language

WSDL is based on XML. It is a simple XML document A WSDL document describes a web service using these

major elements

<types> The data types used by the web service

<message> The messages used by the web service

<portType> The operations performed by the web service

<binding> The message format and protocol details for eachport used by the web service

<service> The address location of the Web Service



WSDL

<type>

<messages>

<xsd:simpleType name="CreditRating">

<xsd:restriction base="xsd:string">

<xsd:enumeration value="GOOD" />

<xsd:enumeration value="AVERAGE" />

<xsd:enumeration value="BAD" />

<xsd:enumeration value="UNKNOWN" />

</xsd:restriction>

</xsd:simpleType>

<s1:message name="addCustomer ">

<s1:part element="s2:addCustomer " name="addCustomer " />

</s1:message>

<s1:message name="addCustomerResponse">

<s1:part element="s2:addCustomerResponse"

name="addCustomerResponse" /></s1:message>



WSDL

<porttype>

<s1:portType name="CustomerServicePort">

<s1:operation name="addCustomer ">

<s1:input message="s2:addCustomer " />

<s1:output message="s2:addCustomerResponse" /><s1:fault message="s2:customerServiceFault" name="customerServiceFault"

/>

</s1:operation>

</ s1:portType>



WSDL <binding>

<s1:binding name="CustomerServiceSoapBinding"type="s2:CustomerServicePort">

<s4:binding style="document"

transport="http://schemas.xmlsoap.org/soap/http" />

<s1:operation name="addCustomer ">

<s4:operation soapAction="addCustomer " style="document" />

<s1:input>

<wsp:Policy><wsp:PolicyReference URI="#Auth.xml" />

</wsp:Policy>

<s4:header message="s2:customerServiceRequestHeader "

part="request_header " use="literal" />

<s4:body use="literal" />

</s1:input>

<s1:output>

<s4:header message="s2:customerServiceResponseHeader "

part="response_header " use="literal" />

<s4:body use="literal" />

</s1:output>

<s1:fault name="customerServiceFault">

<s4:fault name="customerServiceFault" use="literal" /></s1:fault>



WSDL

<service>

<s1:service name="CustomerService">

<s1:port binding="s2:CustomerServiceSoapBinding"

name="CustomerServicePort">

<s4:address location= "https://esp-

int.cable.comcast.com:443/CustomerService/10.03" /></s1:port>

</s1:service>



What is UDDI?

UDDI is a directory service where companies can

register and search for Web services.

UDDI stands for Universal Description, Discovery andIntegration

UDDI is a directory of web service interfaces described

by WSDL

UDDI communicates via SOAP



WSDL UDDI Relationship



What is XML

XML stands for EXtensible Markup Language

XML is a markup language much like HTML

XML was designed to carry data, not to display data XML tags are not predefined. You must define your own

tags

XML is designed to be self-descriptive



XML Tree

XML documents form a tree structure that starts at "the root" and

branches to "the leaves".

XML documents use a self-describing and simple syntax:

<?xml version="1.0" encoding="ISO-8859-1"?>

<note>

<to>abc</to>

<from>xyz</from>

<heading>Reminder</heading>

<body>Don't forget me this weekend!

ABCD

</body>

</note>

XML

Declaration

Root element

Child

Elements

Element

Tag



XML Syntax Rules

All XML Elements Must Have a Closing Tag

<message>This is correct</message>

XML Elements Must be Properly Nested

<b><i>This is incorrect</b></i><b><i>This is correct</i></b>

XML Tags are Case Sensitive

<Message>This is incorrect</message>

XML Documents Must Have a Root Element



XML DTD

The purpose of a DTD is to define the structure of an XML

document.

The DTD consists of the following elements:

Elements

Attributes Entities

PCDATA

CDATA

<!DOCTYPE note

[<!ELEMENT note (to,from,heading,body)>

<!ELEMENT to (#PCDATA)>

<!ELEMENT from (#PCDATA)>

<!ELEMENT heading (#PCDATA)>

<!ELEMENT body (#PCDATA)>

]>



XML Namespaces

XML Namespaces provide a method to avoid element name conflicts.

The xmlns Attribute

When using prefixes in XML, a namespace for the prefix must be defined.

The namespace is defined by the xmlns attribute in the start tag of anelement.

The namespace declaration has the following syntax. xmlns: prefix ="URI ". When a namespace is defined for an element, all child elements with the

same prefix are associated with the same namespace.

<root><h:table xmlns:h="http://www.w3.org/TR/html4/">

<h:tr><h:td>Apples</h:td><h:td>Bananas</h:td>

</h:tr></h:table><f:table xmlns:f="http://www.w3schools.com/furniture">

<f:name>African Coffee Table</f:name><f:width>80</f:width><f:length>120</f:length>

</f:table></root>



XML CSS

With CSS (Cascading Style Sheets) you can add display

information to an XML document.

So CSS is used to format an XML document

In order to link a XML to the CSS file, the following tag should

be included in the XML:

<?xml-stylesheet type="text/css"

href =“note_format.css"?>

Body note_format.css{

background-color: #ffffff;

width: 100%;

}



XSL

XSL stands for EXtensible Stylesheet Language

CSS = Style Sheets for HTML

XSL = Style Sheets for XML XSL consists of three parts:

XSLT - a language for transforming XML documents

XPath - a language for navigating in XML documents

XSL-FO - a language for formatting XML documents



XSLT

XSLT stands for XSL Transformations

XSLT is the most important part of XSL

XSLT transforms an XML document into another XMLdocument another type of document that is recognized

by a browser, like HTML and XHTML

XSLT uses XPath to navigate in XML documents



XSLT - Transformation

Following is an example of a XML document that has to transformed to a

XHTML document:


<?xml-stylesheet type="text/xsl" href="cdcatalog.xsl"?>

<catalog><cd>

<title>Empire Burlesque</title>

<artist>Bob Dylan</artist>

<country>USA</country>

<company>Columbia</company>

<price>10.90</price><year>1985</year>

</cd>

.

.

</catalog>



Create an XSL Style Sheet


<xsl:stylesheet version="1.0”

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"><xsl:template match="/">

<html>

<body>

<h2>My CD Collection</h2>

<table border="1">

<tr bgcolor="#9acd32">

<th>Title</th>

<th>Artist</th>

</tr>

<xsl:for-each select="catalog/cd">

<tr>

<td><xsl:value-of select="title"/></td>

<td><xsl:value-of select="artist"/></td></tr>

</xsl:for-each>

</table>

</body>

</html>

</xsl:template></xsl:stylesheet>

X Path expression



The XML when viewed in the browser will look as shown

below: