net 1

1
Network (internet) applications

• WWW
• Client-server
• Client server side processing
• (Web services)

2
World Wide Web
Internet
Web server
Borg
Public_html
Index.html

• Parts of the puzzle
• URL
• HTTP
• HTML

Web browser
Your Machine
3
HTTP Hyper Text Transfer Protocol

• Lightweight protocol that browsers and servers
  use to communicate with one another
• Internet protocol for transferring Web pages
• Runs in the application layer of the TCP/IP model
• HTTP session begins when a clients browser
  requests a Web page. Once the server responds by
  sending the page requested, the HTTP session ends

4
GET /index.html HTTP/1.1User-Agent
Lynx/2.4Connection Keep-AliveHost
www.openaccess.comAccept text/html
client request
Server response
HTTP/1.1 200 OKDate Thu, 22 July 1998 184055
GMTServer Apache 1.3.5 (Unix)
PHP/3.0.6Last-Modified Mon, 19 July 1997
160322 GMTContent-Type text/htmlContent-Lengt
h 12987...
MIME type (Multipurpose Internet Mail Extension)
5
HTTP is stateless!!!

• stateless because every request that a browser
  makes opens a new connection that is immediately
  closed after the document is returned
• even a web page with many objects (graphics,
  sound, video, etc) requires separate HTTP
  requests for each object
• each operation is unaware of any other connection
• the server cannot maintain state information
  about successive requests easily

6
Client-Server Model
Not mainframe-terminal, not necessarily big vs.
small (rather specialized)
7
Type of servers

• Database servers
• Web servers
• Mail servers
• Print Servers
• Object servers
• Groupware servers
• etc

8
A three-tier architecture
What is middleware?
9
Peer-to-peer vs. Client-Server

• The new hype
• Uniform role of all nodes
• Direct communication
• Decentralized control
• Scalable

10
Web client-server

• Web client (browser) an application program that
  runs on a client computer and requests and
  displays web pages
• can also support other features such as email and
  newsgroups
• Web server a server-side application program
  that runs on a host computer and responds to
  requests for web pages

11
Commercial Web browsers

• Statistics from August 20021
• Internet Explorer (96)
• Netscape Navigator (3.4)
• Other browsers (0.6)
• Opera fastest browser
• NeoPlanet - customizable, including skins
• How has IE become such a dominant player in the
  browser market?

1Source http//www.statmarket.com/cgi-bin/sm.cgi?
smfeatureweek_stat retrieved Sept. 15, 2002.
12
Web client/server communication

• Like any other client/server application, web
  browsers and servers need a way to
• Locate each other so they can send requests and
  responses back and forth
• Uniform Resource Locator (URL)
• Communicate with one another
• Hypertext Transport Protocols (HTTP)
• (See networking section)

13
(X)HTML

• Hypertext Markup Language
• presentation language
• embedded text that tells the clients browser how
  to display the page elements
• standard formatting language that all browsers
  understand
• theoretically !
• example tag
• lth1gt ECMM 6000 lt/h1gt

ECMM 6000
14
Interactivity

• HTML is a presentation language not a
  programming language
• controls the appearance of the information on the
  clients screen but does not support processing
  or manipulating information
• early web browsers were limited to displaying
  static pages
• But many business applications require
  interactivity ? Client-side server-side
  processing

15
Thin vs. Fat Clients

• where the processing takes place
• Early browsers were thin clients primary
  function was to display web documents containing
  text and simple graphics
• Todays browsers are not thin, they provide a
  great deal of functionality and processing on the
  client side
• Scripting, active object support, email, web page
  authoring, audio, streaming media, Instant
  messaging

16
Client-side processing

• Examples
• HTML
• Cascading style sheets (CSS)
• JavaScript
• VBScript
• Applet
• Plug-ins

17
HTML

• lthtmlgt
• ltTITLEgt HTML HST Calculator lt/TITLEgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3gtHST Calculator lt/H3gt
• To compute the amount of HST you need to pay
• take the price of the item and multiply it by
  0.15
• lt/BODYgt
• lt/htmlgt

18
Client-side interactivity

• Forms were added to HTML to provide data entry
• radio buttons, check boxed, drop-down selection
  lists
• Still, no processing on the client side
• Solution, embed the necessary program logic in
  the HTML stream and let the browser execute the
  instructions on the client side

19
2. Plug-ins

• A plug-in is a software routine that extends the
  capability of a larger application
• Allows a browser to process nonstandard, often
  proprietary animation, video, and audio files
  embedded in HTML documents

20
3. Scripts

• a Script is a set of macro-like instructions
• JavaScript, Jscript, VBScript
• Scripts are normally embedded in an HTML document
  as a text string between a set of ltscriptgt tags
  or reference a script file between the tags
• can control the objects, content, and
  interactions within the browser
• when first introduced one of its major purposes
  was to validate the completeness and accuracy of
  data input to a browser-based form
• See http//www.w3.org/TR/REChtml40/interact/script
  s.html for details

21
3. Scripts (continued)

• Various script functions
• Client-side form validation
• Client-side calculations
• Client-side lookup databases
• Client-side image maps
• Providing interactive feedback
• Personalizing a document before it is displayed
• Manipulating Java applets or ActiveX objects
  within a page

Source Turban et al., Appendix C, Table C.1
22
Forms and JavaScript
ltHTMLgt ltTITLEgt HST calculator lt/TITLEgt
ltSCRIPT LANGUAGE"JavaScript"gt function
HST(theForm) var
priceparseInt(theForm.price.value)
var hstprice.15 theForm.result.valu
ehst lt/SCRIPTgt ltBODYgt
ltCENTERgt ltH3gtHST Calculator lt/H3gt
ltFORMgt ltinput type"text"
name"price" size"6" value"0"gt
ltinput type"button" value"HST"
onClick"HST(this.form)"gt ltinput
type"text" name"result" size"6" value""gt
lt/FORMgt lt/BODYgt lt/HTMLgt
http//www.cs.dal.ca/tt/ECMM6010/hst.htm
23
DOM Document Object Model
24
JavaScript example form validation
ltHTMLgt ltHEADgt ltTITLEgtE-Commercelt/TITLE
gt lt/HEADgt ltSCRIPT LANGUAGE
"JavaScript"gt function valcheck()
if(document.forms0.elements0.value
"") alert("Please enter a
name") lt/SCRIPTgt ltBODY
BGCOLOR "FFFFFF"gt ltH2gtJavaScript
Validationlt/H2gt ltFORM METHOD POSTgt
ltPgt Name ltINPUT TYPE "text" NAME "T1"
SIZE "32"gt ltPgt ltINPUT TYPE"button"
NAME"B1" VALUE"Submit" onClick"valcheck()"gt
lt/FORMgt lt/BODYgt lt/HTMLgt
http//www.cs.dal.ca/tt/ECMM6010/validate.htm
25
JavaScript versions

• Originally introduced by Netscape
• Different versions of JavaScript (Jscript)
• ECMA standard (ECMA International is an industry
  association founded in 1961 and dedicated to the
  standardization of Information and Communication
  Technology (ICT) Systems http//www.ecma-internat
  ional.org)
• Challenge of programming for different version
  and support of JavaScript (? use object and
  method detection)

26
VBScript
ltHTMLgt ltTITLEgt HST calculator (VBScript)
lt/TITLEgt ltSCRIPT LANGUAGE"VBScript"gt
Sub HSTButton_OnClick() dim price,
hst priceCInt( Document.Forms( 0
).price.Value) hst price .15
Document.forms( 0 ).result.Value hst
End Sub lt/SCRIPTgt ltBODYgt
ltCENTERgt ltH3gtHST Calculator lt/H3gt
ltFORMgt ltinput type"text"
name"price" size"6" value"0"gt
ltinput type"button" name"HSTButton"
value"HST"gt ltinput type"text"
name"result" size"6" value""gt lt/FORMgt
lt/BODYgt lt/HTMLgt
27
4. Applets

• scripts are not full-featured programming
  languages
• to add more interactivity, applets can be
  downloaded to a client
• applets are small programs executed by an
  interpreter program (included in browser)
• an applets file name is inserted into the body
  of an HTML document between ltappletgt tags
• an applet is stored in a web server file and
  downloaded to the client upon request
• most applets are written in Java
• CANNOT write to clients machine (security)

NOT (anymore) widely supported, but can be still
useful for specific user application
28
Applet (cont.)

• lthtmlgt
• ltTITLEgt HTML and forms sample lt/TITLEgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3gtHST Calculator lt/H3gt
• To compute the amount of HST you need to pay,
  enter the price of the item and
• click the HST Button.ltbrgt
• The information will be sent back to the server
  and your
• GST computed
• ltapplet code"com.mindprod.canadiantax.CanadianTax
  Calculator.class" archive"canadiantax.jar"
  width"600" height"400" vspace"10" hspace"10"
  alt"Sorry, you need Java to run this Applet"gt
• lt/appletgt
• lt/BODYgt
• lt/htmlgt

Another example with mouse interaction
29
Cascading Style Sheets

• Allows you to specify the style of your web page
  elements separately from the structure of your
  document
• separation of presentation and content
• Benefit of greater manageability
• Inline, Header, or External (examples)

30
Cascading style sheet - inline

• lthtmlgt
• ltTITLEgt CSS Inline Example lt/TITLEgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3 STYLE "color 0000FF"gtHST Calculator lt/H3gt
• To compute the amount of HST you need to pay,
  take the price of the item and
• multiply it by 0.15
• ltH3gt End of Instructions lt/H3gt
• lt/BODYgt
• lt/htmlgt

31
Cascading style sheet - header

• lthtmlgt
• ltHEADgt
• ltTITLEgt CSS Header Example lt/TITLEgt
• ltSTYLE TYPE "text/css"gt
• H3 color 0000FF
• Ahover background-color CCFFCC
• .red color red
• lt/STYLEgt
• lt/HEADgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3gtHST Calculator lt/H3gt
• To compute the amount of HST you need to pay,
  take the price of the item and
• multiply it by 0.15 or go to the lta
  hrefjavascript_example.htmlgtjavascript_example.ht
  mllt/Agt

32
Cascading style sheet - external

• lthtmlgt
• ltHEADgt
• ltTITLEgt CSS External Example lt/TITLEgt
• ltLINK REL "stylesheet" TYPE "text/css" HREF
  "styles_example.css"gt
• lt/HEADgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3gtHST Calculator lt/H3gt
• To compute the amount of HST you need to pay,
  take the price of the item and
• multiply it by 0.15 or go to the lta
  hrefjavascript_example.htmlgtjavascript_example.ht
  mllt/Agt
• ltH3gt End of Instructions lt/H3gt
• ltH3 CLASS "red"gtEND OF WEB PAGE lt/H3gt
• lt/BODYgt
• lt/htmlgt

33
Dynamic HTML

• allow any element of a page to be changeable at
  any time
• DHTML is not a language!
• DHTML describes the abstract concept of breaking
  up a page into manipulatable elements, and
  exposing those elements to a scripting language
  which can perform the manipulations
• Often programmed using a combination of HTML,
  Cascading Style Sheets, and JavaScript
• Used for
• Positioning precisely placing blocks of content
  on the page and, if desired, moving these blocks
  around.
• Style modifications on-the-fly altering the
  aesthetics of content on the page.
• Event handling how to relate user events to
  changes in positioning or other style
  modifications.

Source WDVL Dynamic HTML, retrieved from
http//www.wdvl.com/Authoring/DHTML/, September
27, 2002
34
DHTML Object Model

• ltHTMLgt
• ltTITLEgt Javascript sample lt/TITLEgt
• ltSCRIPT LANGUAGE"JavaScript"gt
• function GST(theForm)
• var priceparseInt(theForm.price.value)
• var gstprice.15
• theForm.result.valuegst
• document.body.style.backgroundColor "cyan
• lt/SCRIPTgt
• ltBODY bgcolor"FFFF80"gt
• ltCENTERgt
• ltH3gtHST Calculator lt/H3gt
• ltFORMgt
• ltinput type"text" name"price" size"6"
  value"0"gt
• ltinput type"button" value"GST"
  onClick"GST(this.form)"gt
• ltinput type"text" name"result" size"6"
  value""gt
• lt/FORMgt

35
DHTML Event

• ltHTMLgt
• ltTITLEgt DHTML sample 2 lt/TITLEgt
• ltSCRIPT LANGUAGE"JavaScript"gt
• function GST(theForm)
• var priceparseInt(theForm.price.value)
• var gstprice.15
• theForm.result.valuegst
• document.body.style.backgroundColor "cyan"
• function redtext()
• calctitle.style.color "red"
• lt/SCRIPTgt
• ltBODY bgcolor"FFFF80" ONMOUSEMOVE
  "redtext()"gt
• ltCENTERgt

36
State

• Web is inherently stateless
• Fine for regular browsing
• Many web applications require a series of steps
• Requires the ability to remember the results of
  previous steps
• Example online banking
• enter id and password, system authenticates you,
  should be able to check balances, make payments,
  etc. You shouldnt have to keep re-identifying
  yourself
• maintaining state on server
• imagine a site with 1,000s of hits at any
  instance

37
Cookies
File tt_at_amazon1.txt
session-id-time 1064822400 amazon.com/ 1536 292347
9040 29591135 180892160 29589790 session-id 103-
8845915-6364609 amazon.com/ 1536 2923479040 295911
35 181052160 29589790 ubid-main 430-9692026-3608
944 amazon.com/ 1536 2916341376 31961269 189172160
29589790

• Maintain state by storing a small text file on
  the client computer
• holds information about the user and/or the state
  of the application
• when the browser transmits new data or requests a
  new page, the cookie is returned to the server
  where its contents can be used to remind the
  server of the stat

38
Cookies with server-side databases

• Server-side database holds a set of data that
  reflect the session contents
• Cookie holds the users database access key
• Example (Davis and Benamati, pg. 89-90)
• Amazon.ca
• Customer follows a hyperlink to amazon.ca
• Server stores a set of session data (initial
  contents of the shopping cart) in a database and
  created a session cookie containing the users
  database access key
• Session data and cookie are returned to the
  client as part of the pages HRML stream
• Client browser stores the session data and the
  cookie in memory
• Whenever the customer changes the shopping cart,
  the session data and cookie are transmitted back
  to the server

39
Personalized Web Pages

• Store a cookie which holds the individuals
  information
• The cookie gets uploaded to the server when the
  page is requested to provide the personal
  information

Cookies Security ???
40

• Server-side Processing

41
Web server

• a server-side application program that runs on a
  host computer and responds to requests for web
  pages (i.e. services HTTP requests)
• Other possible functions
• access control
• run scripts/programs
• management and administration of server functions
  and Web site contents
• Log transactions
• Two main commercial web servers
• Apache (64.6)
• Microsoft Internet Information Server (IIS)
  (23.5)
• The Netcraft Web Server Survey, October 2003,
  retrieved from http//www.netcraft.com/survey/,
  Oct. 10, 2002

42
Market Share for Top Servers Across All Domains
August 1995 - October 2003
http//www.netcraft.com/survey/, Oct. 10, 2002
43
Static vs. Dynamic Web pages

• Most basic function of web servers is to
  distribute HTML documents
• HTML Static
• all clients see the same content
• However, eCommerce is more than just displaying a
  static catalog
• we want to customize the web page to suit the
  information the user is looking for?
• We want to send real-time data (i.e. current
  date/time)?
• We want to do sophisticated processing on
  user-supplied data and report results

44
Client-side vs. Server-side processing

• Dynamically create content that doesnt reside in
  the HTML pages
• Create and modify information on-the-fly
• Data is often part of databases that resides
  elsewhere (on other disks or even other servers)

45
Client- vs. Server-side Processing

• Client
• Validation, interactivity, enhancing web pages
• Reduces traffic to/from server
• Reduces the amount of the work the server needs
  to perform (run 100 programs on 100 client
  computers instead of 100 program on a server)
• Dependent on browser functionality (e.g. is the
  specific technology supported by the individual
  browser)
• Scripts are visible
• Great way to distribute little application
  programs (e.g. currency converter)
• Server
• Generate custom responses for clients
• Runs exclusively on the server no
  cross-platform issues
• Scripts not visible to client more proprietary

46
Server-side processing

• Need an intermediary to take the inquiries from
  the client and gather the information from the
  database
• ? middleware
• ? three-tier-architecture

47
CGI Programming (Common Gateway Interface)

• Set of standard methods and routines used to
  write stand-alone software programs that know how
  to receive requests from a Web server and return
  data to the server. 1
• a specification for transferring information
  between a Web server and a CGI program.2
• Allows you to3
• create an executable that the web server may call
  on demand
• pass incoming HTTP GET or POST data to the CGI
  script
• send CGI generated answers back to the browser
• CGI programs can be written in a variety of
  programming languages Perl, VB, C/C, Java,
  etc.

Sources 1) Turban, Web Programming, Appendix C.
2) Webopedia. Retrieved Sept. 22, 2002 from
http//www.webopedia.com/TERM/D/DOM.html,. 3)CGI
(Common Gateway Interface), Selena Sol, October
4, 1999, retrieved Sept. 22, 2002 from
http//www.wdvl.com/Authoring/Tools/Tutorial/cgi.h
tml,.
48
Perl

• "Practical Extraction and Report Language"
• freely available for most operating systems
• powerful string manipulation functions
• easy (?) to learn can be used to implement most
  sophisticated processing
• monolithic code
• Good (quick) introduction http//www.cgi101.com/
• presentation by Richard Carpenter

49
CGI Programming (Common Gateway Interface)

• ltHTMLgt
• ltHEADgt
• ltTITLEgtSimple CGI Examplelt/TITLEgt
• lt/HEADgt
•  
• ltBODY BGCOLOR "FFFF80"gt
• ltA href"http//www.cs.dal.ca/tt/cgi-bin/hello.cg
  i"gt Hello World CGI Scriptlt/Agt
• lt/BODYgt
• lt/HTMLgt 

50
hello.cgi

• !/opt/bin/perl
• hello.cgi a simple Perl CGI example
• print "Content-type text/html\n\n"
• Note that we output two carriage returns after
  the
• content type. This is very important as it marks
• the end of the CGI "header" and the beginning of
• the document to be sent to the browser.
• print "ltheadgt\n"
• print "lttitlegtHello World CGIlt/titlegt\n"
• print "lt/headgt\n"
• print "ltbodygt\n"
• print "lth1gtHello, World !lt/h1gt\n"
• print "lt/bodygt\n"

Where the perl interpreter is located
Two carriage returns
Generate the HTML head body
http//www.cs.dal.ca/tt/cgi-bin/hello.cgi
51
PERL ltlt PRINT Command

• Doesnt require a print statement on every line

• print "Content-type text/html\n\n"
• print ltlt ending_print_tag
• ltheadgt
• lttitlegtHello, Worldlt/titlegt
• lt/headgt
• ltbodygt
• lth1gtHello, World!lt/h1gt
• lt/bodygt
• ending_print_tag

52
Passing Data

• Normally use forms to pass user input data to a
  web server

lthtmlgt ltheadgtlttitlegtPerl Examplelt/titlegtlt/headgt ltb
odygt ltpgtPlease enter your namelt/pgt ltform
method"GET" action"http//www.cs.dal.ca/tt/cgi-
bin/getenv.cgi"gt ltinput type"text" name"Name"
size"20"gt ltinput type"submit" value"Submit"
name"B1"gt lt/formgt lt/bodygt lt/htmlgt
http//www.cs.dal.ca/tt/ECMM6010/PerlExample.htm
53
GET vs. POST

• Two methods that data can be sent to the CGI
  program
• GET
• GET sends data appended to the URL
  stringhttp//www.domain.com/dir/file?data1data2
  data3
• POST
• POST sends data after all the request headers
  have been sent to the server
• Uses the content length header to let the CGI
  program know how much data to read

54
Processing Input Data
!/opt/bin/perl hello.cgi a simple Perl CGI
example print "Content-type text/html\n\n" re
ad(STDIN, buffer, ENV'CONTENT_LENGTH') _at_pair
s split(//, buffer) _at_pairs split(//,
ENV'QUERY_STRING') foreach pair (_at_pairs)
(name, value) split(//, pair)
value tr// / value
s/(a-fA-F0-9a-fA-F0-9)/pack("C",
hex(1))/eg FORMname
value print ltlt
"ending_print_tag" lttitlegtHello
FORM'name'lt/titlegt lt/headgt ltbodygt lth1gtHello
FORM'name'lt/h1gt lt/bodygt ending_print_tag
Used for POST
Used for GET
55
Most common CGI Bugs

• Make sure your file and directory are executable
• Give both your file and directories read and
  execute permissions (chmod 755 file.cgi)
• Perl scripts will never work if the permissions
  on the file are 777
• Make sure perl is in the directory you specified
  ( /opt/bin/perl )
• Check that your program executes ok (type it in
  at the command line hello2.cgi )
• Have the interpreter check the syntax without
  actually running it (perl cw hello2.cgi)
• Make sure there are no hidden characters when
  transferring files from PC (e.g. M)

56
Servlets

• CGI programs in Java
• Servlets are Java programs that extend
  HttpServlets and implementing specific methods
  that are called by a get or post request
• Discussed in Darrel Ince, Developing Distributed
  and E-Commerce Applications, Chapter 7

57
Limitations of CGI Programming

• CGI programs are separate executables or
  interpreted scripts
• Other limitations
• CGI introduces security holes
• Limited by HTTP
• CGI can be ugly

http//wdvl.internet.com/Authoring/Scripting/WebWa
re/Server/CGIsux.html
58
Solution

• Embed the processing into the web server (and web
  page) itself
• Other server-side scripting languages
• Server Side Includes (SSI)
• Microsofts Active Server Pages (ASP)
• Apaches Hypertext Preprocessor (PHP)
• Java Server Pages (JSP)
• ColdFusions Markup Language (CFML)

59
Server-side scripts

• A Web page that contains script statements
  interspersed with HTML tags
• lt .. gt specialized script tag
• When the web page is processed it is first handed
  off to the appropriate server-side script
  processor
• .shtml, .asp, .php, .cfm
• The script code gets executed and the resulting
  page sent back to the browser via Web server

60
SSI (Server Side Includes)

• Commands are integrated into an HTML page using
  special tags
• The web server understands the special tags and
  translates the code on the fly
• The result is embedded into the HTML document
  which is then passed to the browser
• Syntax
• lt!--command arg1"value1 arg2"value2 ... --gt
• Warnings
• Can be costly to parse files on heavily loaded
  servers
• Can be a security risk

61
hello4.shtml
lthtmlgt lttitlegtHello Worldlt/titlegt lt/headgt ltbodygt lt
h1gtHello Worldlt/h1gt The Current Date
is lt!--echo var"DATE_LOCAL"--gt ltbrgt lt!--exec
cmd"date"--gt lt/bodygt lt/htmlgt
62
SSI (old technology)

• What happens
• Server gets request for a page (.shtml)
• Server checks the page for SSI commands
• Server executes those commands and inserts new
  values into the page
• Server send the new page to the browser

63
Server Pages

• Java Server Pages (Sun) .jps
• Active Server Pages (Microsoft) .asp
• Instructions for the server are included in the
  web page
• The server notices the extension and looks for
  those instructions and executes them

64
JavaServer Pages (JSP) Servlets

• Java servlets small Java programs that run on a
  Web server and build Web pages. They are
  specified in a web page and run on the web server
  to modify the web page before it is sent to the
  user.
• Java Server Pages web page coding standard to
  combine static HTML with dynamically-generated
  HTML (created by JSP scripts, and Java)

65
date.jsp
ltHTMLgt ltHEADgt ltTITLEgtJSP Examplelt/TITLEgt
lt/HEADgt ltBODY BGCOLOR"ffffcc"gt ltCENTERgt
lth2gt The current date is lt new
java.util.Date()gt. lt/h2gt lt/CENTERgt lt/BODYgt
lt/HTMLgt
66
Active Server Pages

• Microsofts version to dynamically create Web
  pages
• Utilizes VBScript or Jscript
• Has a robust set of objects for serious
  programming, allows developers to code custom
  tags, and can instantiate server side resources
  (COM components)

67
hello.asp
lt_at_ LanguageVBScript gt ltHTMLgt ltHEADgt
ltTITLEgtExample 1lt/TITLEgt lt/HEADgt ltBODY
bgcolorLime aLinkDarkTurquoisegt ltPgt lt/Pgt lt
Response.Write("Hello, world!") gt lt/BODYgt
lt/HTMLgt
68
Further topics

• .NET
• J2EE
• WebSphere
• Web Services ? Semantic web

69
Web service architecture
Adopted from Clabby, 2002
70
SOAP

• Simple Object Access Protocol
• XML-based protocol
• Exchange of information between applications over
  HTTP
• Seems to become the widely accepted solution to
  electronic data interchange (EDI) and remote
  procedure call (RPC, CORBA, etc)

71
Latest Web Service Architecture (W3C, 2004)
72
References

• Definitions from Webopedia http//www.webopedia.c
  om
• Turban, Web Programming, Appendix C.
• Selena Sol Tutorials http//www.wdvl.com/Authorin
  g/Tools/Tutorial/