Web Architecture SCJ UTM

7/28/2019 Web Architecture SCJ UTM

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Basic WEB Architecture

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Data Driven WEB Architecture

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Recent WEB Applications Architecture

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Client Tier

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Service Tier

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The Web as a Platform

for Running Applications

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Service Oriented Application (SOA)

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Front-End

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Front-End

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Middle Layer Data Link

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Back-End- Server Site

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GROUP DISCUSSION

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What is XML?

eXtensible Markup Language, is aspecification for creating custom markup

languages

W3C RecommendationPrimary purpose is to help computers to share

data

XML is meta-language. This means that youuse it for creating languages.

XML is an extensive concept.


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XML Document

Every XML-document is text-based=> sharing data between different computers!

=> sharing data in Internet!

=> platform independence!


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Binary vs. Text

Problems with Binary format Platform depence

Firewalls

Hard to debug Inspecting the file can be hard

Since XML is text-based, it does not have the

problems mentioned above.What are the disadvantages in text format?


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XML Doc Advantages

Easy data sharing, text documents are readablebetween any device.

Documents can be modified with any text editor.

Possible to understand the contents of the xml-

document just by looking at it with text editor.Easy to manipulate via programming languages

Two levels of correctness: Well formed and Valid.


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.doc file format

Windows

MS Word 2000Mac OS X

Since .doc is closed binary-format,

there are very few alternatives for

word processors that fully support

the docfile format

0101011010101010001010

1010101110101010001011

1010101110101010110101

1110101010101010101010

d fil f t (Offi O


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.docx file format (Office Open

XML)

Windows

MS Word 2007Mac OS X

Hopefully in the future there

will be loads of free programs

that support this new open

and easy access file format

title

.

.

Now the format is

open and it's much

easier to access


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SGML vs. XML

SGML: Standard Generalized Markup Language

XML

HTML

(.html)

XHTML

(.xhtml)

MathML

(.mml)

OOXML

(.docx)


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XML Meta Language

XML is meta language, which you can use to createyour own markup languages.

There are several XML Markup Languages made fordifferent purposes

All the languages have common xml-rulesLanguages: XHTML, OOXML, Open Document,

RSS, SVG, SOAP, SMIL, MathML...

List: http://en.wikipedia.org/wiki/List_of_XML_markup_languages


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XHTML - Example

Minimal XHTML 1.0 Document

This is a minimal XHTML 1.0

document.


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SVG - Example


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MathML (Open Office)

x=

...

x = {-b +-sqrt{b^{2}-4{ac}} } over {2 {a}}


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RSS 2.0 - Example

W3Schools Home Page

http://www.w3schools.com

Free web building tutorials

RSS Tutorialhttp://www.w3schools.com/rss

New RSS tutorial on W3Schools

XML Tutorial

http://www.w3schools.com/xmlNew XML tutorial on W3Schools


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XML Editors

XML SpyEditiX

Microsoft XML Notepad

Visual XML

XML Viewer

Xeena

XML Styler, Morphon, XML Writer


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WELL FORMED XML -DOCUMENT

Rules that Apply to Every XML-Document


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Correctness

There are two levels of correctness of an XMLdocument:

1. Well-formed. A well-formed document conforms

to all of XML's syntax rules.

2. Valid. A valid document additionally conforms to

some semantic rules.

Let's first look at the XML's syntax rules (1).


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Simple Generic XML Example

Introduction to XML

XML is ...


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XML-Declaration

XML-declaration is optional in XML 1.0, mandatoryin 1.1. Recommendation: use it.

Version: 1.0 or 1.1

Encoding: character encoding, default utf-8Standalone:

is the xml-document linked to external markup declaration

yes: no external markup declarations

no: can have external markup declaration (open issue..) default: "no"


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Comparing Declarations

Introduction to XML

XML is ...

Introduction to XML

XML is ...

Same Declaration


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Element vs. Tag vs. Attribute

Element consists ofstart tag, optional contentand anend tag: Introduction to XML

Start tag

Content Introduction to XML

End tag

Start tag may have attribute


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Rules about Elements

Only one root - element

Every element contains starting tag and an ending tag

Content is optional: Empty element

Tag names are case-sensitive:

Elements must be ended with the end tag in correct order:

problem here


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Rules about Attributes

XML elements can have attributes in thestart tag.

Attributes must be quoted:


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Naming Tags

Names can contain letters, numbers, and othercharacters

Names must not start with a number or

punctuation characterNames must not start with the letters xml (or

XML, or Xml, etc)

Names cannot contain spaces


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Well-Formed XML

XML document is well-formed if it follows thesyntax rules.

XML document must be well-formed!

it's not an xml-document, if it does not follow therules..

Is this Well-Formed XML


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Document?


This is a minimal XHTML 1.0document.



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Document?




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VALID XML DOCUMENT

Defining the Structure for XML documents


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Valid XML

XML document is valid if 1) It is well formed AND

2) It follows some semantic rules

XML document is usually linked to an external file,

that has semantic rules for the document. The file can be dtd (.dtd) or schema (.xsd)

Semantic rules?

Name of tags, order of elements


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DTD Linking



document.

Rules for XHTML elements (order,

names, etc)


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DTD Linking

Defines the structure, tag names and

order for all xhtml - documents

W3C has created XML-language "XHTML"

by defining it's rules in DTD.


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Is this valid XML Document?



1. There is no DTD! What language is this? MathML? SVG? XHTML?

2. Assuming this is XHTML, what version of XHTML? Transitional? Strict?

3. Assuming this is XHTML strict, does "jorma" tag belong to XHTML Language?


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Invalid XHTML-document



document.

C S


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Validating with W3C Service

I lid XHTML i B ?


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Invalid XHTML in Browser?

May work... or not. Browser tries to detect the errors and tries to understand

them. If it works with one browser, are you certain that it works with all other

browsers? And with all the versions with the browsers? What about browsers

in handheld devices?

And it might work now, but what about future? How will Firefox 5.0 handle

incorrect web pages?

I lid XML i G l


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Invalid XML in General

Because of HTML heritage, browsers try tounderstand invalid XHTML-pages

This is not the case in other XML-languages.

In general, if XML-document is invalid, theprocessing of the document is cancelled.


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JavaScript Object Notation

(JSON)

JSON


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JSON

JSON (JavaScript Object Notation) is a lightweightdata-interchange format.

It is easy for humans to read and write.

It is easy for machines to parse and generate.

It is based on a subset of the JavaScriptProgramming Language, Standard ECMA-262 3rdEdition - December 1999.

JSON is a text format that is completely language

independent.These properties make JSON an ideal data-

interchange language.

Wh JSON?


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Why JSON?

Because JSON is lightweight, easy to understand,manipulate and generate, it has almost replaced XMLwhich was used previously as the only data-interchange format.

JSON is preferable because of the following reasons:

XML is heavier than JSON to parse XML, we have to use xPath which is an overhead

removed in JSON because JSON is native to JavaScript

XML uses tags to describe user data and tags increase thesize of data

JSON St t


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JSON Structures

JSON is built on two structures:A collection of name/value pairs.

In various languages, this is realized as an object,

record, dictionary, hash table, keyed list, or associative

array.

An ordered list of values.

In most languages, this is realized as an array, vector,

list, or sequence.

S t f JSON


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Syntax of JSON

ObjectAn objectis an unordered set of name/value pairs.

An object begins with { (left brace) and ends with } (right

brace). Each name is followed by : (colon) and the name/value pairs

are separated by , (comma).

S t f JSON


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Syntax of JSON

Array

An arrayis an ordered collection of values.

An array begins with [ (left bracket) and ends with ] (right

bracket). Values are separated by , (comma).

S t f JSON


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Syntax of JSON

A value can be a stringin double quotes, or anumber, or true or false or null, or an objector

an array. These structures can be nested.

A stringis a collection of zero or more Unicodecharacters, wrapped in double quotes, using

backslash escapes. A character is represented

as a single character string. A string is very

much like a C or Java string.

JSON E l


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JSON Example

{ students :[

{id":1, "name":"Adnan Sohail"},

{id":2, "name":"Irfan Razzaq"}]

}

XML Example


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XML Example

1

Adnan Sohail

2

Irfan Razzaq

Validating JSON &


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gJSON Security

JavaScripts built-in method eval() is used to validatea JSON string.

Note:

Use eval() only when the source is authentic and trusted

which means use it only if you are sure that the stringpassed to it is a valid JSON string

When youve security risks usevar myObject = myJSONtext.parseJSON();

Which is available in http://www.json.org/json.js

but eval() is faster than parseJSON()

Using JSON APIs
http://www.json.org/json.jshttp://www.json.org/json.js


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Using JSON APIs

JSON strings can be easily generated using JSONAPIs available at http://json.org

There are two main classes available in org.json.*

package

org.json.JSONObject

org.json.JSONArray

Strings can be generating from objects ofJSONObject orJSONArray using their

toString() methods

Benefits of JSON over XML
http://json.org/http://json.org/


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Benefits of JSON over XML

JSON supports data types like string, integer,boolean etc.

JSON is native data format for JavaScript and

therefore it faster for the browser to read and

understand.As JSON contains no tags but data and therefore

less data to be transferred between client and the

server. So, its lighter than XML.

Easy for humans to read and write.

JSON References


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JSON References

http://www.xul.fr/en-xml-ajax.htmlhttp://www.xul.fr/ajax-javascript-json.html

http://json.org/

http://www.json.org/java/


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WEB SERVICE DESCRIPTION

LANGUAGE (WSDL)

I t d ti


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Introduction

WSDL is an XML language that contains

information about the interface semantics andadministrivia of a call to a Web Service

Once you develop a Web Service you publishits description and a link to it in a UDDI

repository so that potential users can find itWhen someone wants to use your service,

they request the WSDL file in order to find outthe location of the service, the function calls

and how to access themThen they use this information in your WSDL

file to form a SOAP request to the computer

Definitions


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Definitions

Definitions:- WSDL is an XML-based language used to

define Web Services and describe how to

access them.

- WSLD is an XML format for describingnetwork services as a set of endpoints

operating on messages containing either

document-oriented or procedure-oriented

information.

Working of WSDL


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Working of WSDL

Figure 1. A client invoking a Web service.

Working of WSDL contd


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Working of WSDL contd.

Figure 2. WSDL terminology used for describing Web services.

Working of WSDL (with Java)


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Working of WSDL (with Java)

contd.

Where does it fit in?


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Where does it fit in?

Wh t i UDDI?


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What is UDDI? Universal Description Discovery and Integration

Industry-wide initiative supporting web services

Specifications Schemas for service description

Schemas for business (service implementers)description

Developed on industry standards (XML, HTTP, TCP/IP,SOAP)

Applies equally to XML and non-XML web services

Implementation Public web service registry and development

resources


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Industry-Wide Project Support

All major technology providers

Global corporations

Strong resource and product commitment

Roadmap for transition to standards body

Unprecedented collaboration

XML and Web Services recognized as core standards Competition on services built on a common model

Technology, platform, and development languageneutral

What Problems Do We Solve?


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What Problems Do We Solve?An organization needs to

create 400 electronic

relationships with

partners, each with itsown standards and

protocols

Broader

B2B

A small business wants to

be plugged in to every

marketplace in the world,

but doesnt know how

Smarter

Search

A B2B marketplace cannot

get catalog data for

relevant suppliers in its

industry, along with

connections to shippers,insurers, etc.

Easier

Aggregation

DescribeServices

Discover

Services

Integrate

Them

Together

Provide a standards-based

profile for all electronic

services that are provided.

Includes web sites, other

electronic resources

Web Service

Visibility

Publ ish for

Accessibi l i ty

Foundation for Web Services


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Foundation for Web Services

Ubiquitous Communications: Internet

Universal Data Format: XML

Service Interactions: SOAP

Formal Service Descriptions: WSDL

Broad Industry Support, Simple Process

Publish and Discover Services: UDDI


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UDDI Registry Entries

Standards Bodies,Agencies, Programmers,Publishers registerspecifications for theirService Types

Service providers registerprecise information about

themselves and their Webservices


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Business name

General business description

Any number of languages

Contact info

Names, phone numbers,

fax numbers, web sites, etc.

Known identifiers

List of unique identifiers for a business

D-U-N-S, Thomas, domain name, stock ticker

symbol, other


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Business categories

3 base taxonomies in V1

Industry: NAICS (Industry codes - US Govt.) Product/Services: UNSPSC (ECCMA)

Location: Geographical taxonomy (ISO 3166)

easy extension in upcoming releases


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New set of information businesses useto describe how to do e-commerce

with them

Nested model Business process (functional)

Service specifications (technical)

Binding information (implementation)

Programming/platform/

implementation agnostic

Services can also be categorized

How UDDI Works


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How UDDI Works

UDDI Registry

3.UDDI Registry assigns a programmatically

unique identifier to each service andregistration

Marketplaces, search

engines, and business

applications query the

registry to discover services

at other companies and to

facilitate integration

4.

Service Types

1.

ImplementationsImplementers

populate the

registry withdescriptions of

their businesses

and the services

they expose

2.

Large businesses

apply the same

architecture and

technologies internally

5.

Software companies, standards

bodies, and developers populate

the registry with descriptions(specifications) of types of

services

Public Registry Operation


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Public Registry Operation

IBM

HP (planned)

Microsoftother

other

Peer registry nodes (websites)

Information registered

with any node

Registrations replicated

on a daily basis

Complete set ofregistered records

available at all nodes

Common set of

SOAP APIs supported

by all nodes Compliance enforced

by business contract

All technologies applied

Interoperabilityverified constantly

UDDI.org

queries

Applications

Marketplaces

End Users

Developers

UDDI and SOAP


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UDDI and SOAP

User

UDDISOAP Request

UDDI

SOAP Response

UDDI RegistryNode

HTTPServer

SOAPProcessor

UDDIRegistry Service

B2B DirectoryCreate, View,Update, and Delete

registrations Implementation-neutral

GROUP DISCUSSION


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GROUP DISCUSSION

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