LAB SESSION 1: CGIs
===================

0.- Understand what CGIs are and how they work. A good place to start is:
http://www.jmarshall.com/easy/cgi/

1.- Install Apache. Download Apache from:
http://docencia.ac.upc.edu/FIB/PXC/lab/_cgi/apache-pxc.tar.gz

Some of the directories of Apache are:
apache/htdocs		Where the html pages are
apache/cgi-bin		Where the CGIs are
apache/conf		Where the configuration files are
apache/bin		Where the binary files are

2.- Install the examples of CGIs to the 'cgi-bin' directory:
http://docencia.ac.upc.edu/FIB/PXC/lab/_cgi/cgi-examples.tar

3.- Install the html files  'htdocs' directory:
http://docencia.ac.upc.edu/FIB/PXC/lab/_cgi/pxc-html_en.tar.gz

4.- Configure Apache:
The configuration file is '/apache/conf/httpd.conf'.
ServerRoot "/PATH/apache"	Specifies in which directory is Apache
Port 2345			Specifies in which port Apache will listen

5.- Start Apache:
./apache/bin/httpd -f ./apache/conf/httpd.conf

6.- Check that it's working by typing the 'http://localhost:port' URL in a web
browser.

7.- Create two CGIs that use the html files provided in section 3 to implement
a car rental system. Htdocs/rent.html invokes cgibin/rent with the GET method.
Htdocs/list.html invokes cgi-bin/list with the method POST.

When invoking 'list' CGI it should list all the car rents registered through
the 'rent' CGI.

You can choose in what language you want to implement both CGIs.

APPENDIX
========

With these two examples you can get a better picture of how the GET and POST
methods work:

GET
===

> bash
$ export QUERY_STRING="a=1&b=2"     
$ export REQUEST_METHOD="GET"
$ ./query 
Content-type: text/html

<H1>Query Results</H1>You submitted the following name/value pairs:<p>
<ul>
<li> <code>a = 1</code>
<li> <code>b = 2</code>
</ul>
$

POST
====
$ export REQUEST_METHOD="POST"
$ export CONTENT_TYPE="application/x-www-form-urlencoded"
$ export CONTENT_LENGTH="7"
$ echo "a=1&b=2"|./post-query 
Content-type: text/html

<H1>Query Results</H1>You submitted the following name/value pairs:<p>
<ul>
<li> <code>a = 1</code>
<li> <code>b = 2</code>
</ul>
$ 

TROUBLESHOOTING 
======================================================================

* If you get an 'Segmentation fault' while executing a CGI it might be due to
an "exit(1);" in your code. All exits should be "exit(0).