Perl - State and Cookies

State and Cookies - Perl module P407

Each time you submit a form to a web server using CGI, you start a new program with new variables, and when the server has sent you back its response, that program exits, with a loss of all data in memory. That's fine for a one-screen application, but in practise you'll want to string together a series of forms to make up a shopping application, a bulletin board, or another application. To do this, you'll need to "maitain state" and there are various ways of doing this, which this important module studies.

This topic is presented on public course Using Perl on the Web

Examples from our training material

sweet.pl	Perl, CGI, sessions - application template, first principles
sweeter.pl	Perl, CGI, sessions - complete application template second steps
sweetest.pl	Perl, CGI, sessions - complete application template, full demo

Opentalk forum discussions related to this topic

single to multiple users
detecting browser cookies
detecting bots shoppers
Deleting a cookie

Pictures

Maintaining State
A study in concentration

Background information

Some modules are available for download as a sample of our material or under an Open Training Notes License for free download from http://www.training-notes.co.uk.

Topics covered in this module

The need for non-transient data.
Multiple users.
Schemes for maintaining state.
Which scheme should I use?.
Central database example.
Our database server.
Planning our application.
How it fits together - entry to the site.
The next page.
Modules used.
Persistent cookies.
Shopping cart using hidden fields - example.
Shopping cart using cookie - example.
Templating system.
Security considerations for server side applications.
1. Tainting.
2. Regular expressions from user.
3. validate via email.
4. Data in hidden directories.
5. Credit card info in cookies.
6. https.
7. Avoid \ etc..
8. Temp file names.
9. Save before send.
10. tr.

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