Fall Semester, 2005
Web App Intro
© 2005 All Rights Reserved, SDSU & Roger Whitney
San Diego State University -- This page last updated 15 Sep 2005
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Emerging Technologies
Fall Semester, 2005 Web App Intro |
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© 2005 All Rights Reserved, SDSU & Roger Whitney San Diego State University -- This page last updated 15 Sep 2005 |
Doc 5 Web App Intro
Contents
Copyright ©, All rights reserved. 2005 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA. OpenContent ( http://www.opencontent.org/opl.shtml ) license defines the copyright on this document.
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 2 |
References
Past CS683 lecture notes
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Date |
Chapters |
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Sept 20 |
2, 3, 4 |
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Sept 22 |
5, 6, 7 |
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Sept 27 |
8, 9, 10 |
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Sept 29 |
11, 12, 13 |
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Oct 3 |
14, 15, 16 |
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Oct 6 |
17, 18, 19 |
The chapter numbers above refer to chapters in the book Web Component Development with Zope 3, von Weitershausen, Springer-Verlag, 2005
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 3 |
Datastore
Persistent storage of data
Files, Relational database, Object database
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 4 |
Data - Datastore
Find all data relevant to a request
Convert data from/to Datastore format to usable form
Handle concurrency
Transactions - rollback of a transaction
Business logic
Handle users request
Validate data
Handle concurrent requests
Handle transactions
View
Make users request accessible to program
Convert response in to html, CSS, Javascript etc
Webserver
Intermediary between client and Web app
Stateless
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 5 |
Web browser connects to Web server with request
Web Server handles request
Web Server connects (starts) to program (cgi, etc)
Program gets request
Program frequently connects to database
Program handles requests
Program returns response
Web Server returns response
All connections closed
All requests from Web Browser repeat this process
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 6 |
Common ways to dynamically generate web pages
CGI & Servlets
Web request is passed to a program
VeryBasicServlet>>doGet: aRequest response: aResponse
aResponse write: '<HTML><BODY>
Hello world</BODY></HTML>'.
Server Pages
Code is embedded in html pages
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
" http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd ">
<html xmlns=" http://www.w3.org/1999/xhtml " xml:lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<title>Hi</title>
</head>
<body>
<% response write: 'Hello World'. %>
</body>
</html>
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 7 |
Information (state) from one page must be saved for next page
Information can be stored in
Hidden Fields
Sessions
Database
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 8 |
Data is stored by client
Server can forget about client
<form action="fooBar" method="post" name="Sample">
<input type="hidden" name="name" value="Whitney">
<input type="hidden" name="cart" value="world peace">
<input type="text" name="Credit Card Number" size="40">
<input type="submit" name="submit">
</form>
<a href="bar/foo/index.html" title="Help information">Help</a>
| CS683 Fall 2005 | Doc 5, Web App Intro Slide # 9 |
Problems
Must insure all paths retain data
Pages are coupled
Code depends on order of pages
Reduces code reuse
Name clashes
Field names must be different all other pages in transaction
Security Issues
Server can not track user
Presentation & domain logic mixed
<form action="fooBar" method="post" name="Sample">
<% response
write: 'input type="hidden" name="name" value="'.
userName ifNotNil: [ response write: userName printString].
response
write: '">';
write: '<input type="hidden" name="cart" value="';
cartItems
do: [:each | response write: each printString]
separatedBy: [response write: ', '].
response
write: '">'.
%>
etc.
</form>
Copyright ©, All rights reserved.
2005 SDSU & Roger Whitney, 5500 Campanile Drive, San Diego, CA 92182-7700 USA.
OpenContent license defines the copyright on this document.