nitic cs exp perl

Information Engineering Experiments III Perl/CGI Exercises

Lectures open in 2020

How to run a CGI program

counter.cgi

To count the number of times a web page appears, you need a file to store the count data. Below is a basic Perl CGI program. The program reads the counter file, increases the count, and writes the updated count back to the file and web page.

• src/counter.cgi

 # !/usr/bin/perl
use strict;
use warnings;
use CGI qw( :standard ) ;

# カウンタファイルのパスを指定
my $counter_file = ' counter.txt ' ;

# カウントを取得および更新
open my $fh , ' +< ' , $counter_file or die " Can't open $counter_file : $! " ;
my $count = < $fh >;
$count = 0 unless defined $count ;
$count ++;
seek $fh , 0, 0;
print $fh $count ;
close $fh ;

# HTMLページを出力
print header;
print start_html( ' Counter Page ' );
print " This page has been viewed $count times. " ;
print end_html;

To run this CGI program, follow these steps:

1. Saving the program :

   • Save the above code in a file named counter.cgi .

2. Setting execution permissions :

   • Grant execution permissions to the program file. Open a terminal and run the following command:

     chmod +x src/counter.cgi

3. Configuring XAMPP :

   • Open XAMPP and start the Apache web server.

4. Configuring the CGI Directory :

   • Open the XAMPP configuration file (usually /Applications/XAMPP/etc/httpd.conf ) in the editor and set the CGI directory as follows:

      <Directory "/Applications/XAMPP/cgi-bin">
         AllowOverride None
         Options ExecCGI
         Order allow,deny
         Allow from all
     </Directory>
     

5. Program placement :

   • Copy the counter.cgiファイルをto the /Applications/XAMPP/cgi-bin` directory.
   • It also works with symbolic links. By creating a symbolic link to counter.cgi in /Applications/XAMPP/cgi-bin directory, XAMPP Apache servers can recognize and run it correctly, even if the actual counter.cgi file is located elsewhere. To create a symbolic link, open a terminal and run the following command (replace the path of the actual counter.cgi file and the destination of the link appropriately): $ ln -s src/counter.cgi /Applications/XAMPP/cgi-bin/counter.cgi

This command creates a symbolic link named counter.cgi in /Applications/XAMPP/cgi-bin directory, which points to the actual counter.cgi file. You can then run the CGI program by visiting http://localhost/cgi-bin/counter.cgi using a web browser.

1. Accessed via web browser :
   • Open a web browser and go to http://localhost/cgi-bin/counter.cgi .

That's how the counter program should run and the count should increase every time you access the web page. The counter value is also saved in the counter.txt file, and the program reads the count value from that file.