Python 3 CGI Programming
Copyright (C) 2020 Exforge exforge@x386.xyz
# This document is free text: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# any later version.
# This document is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
# Based on the tutorial at
https://www.tutorialspoint.com/python/python_cgi_programming.htm
# Python2 codes upgraded to Python3
# Operating System: Ubuntu Server 20.04
# HTTP Server: Apache2
# Python Version: python3 (3.8 actually)
# My Server: test1.x11.xyz
# Location on server:
# html files: /var/www/test1.x11.xyz
# cgi files: /var/www/test1.x11.xyz/cgi
# 1.1. Enable cgi for Apache
sudo a2enmod cgid
sudo systemctl restart apache2
# 1.2. Enable a cgi directory for the site
# Add to the vhost site conf
#_____________________________________________________________
ScriptAlias /bin/ "/var/www/test1.x11.xyz/cgi/"
<Directory "/var/www/test1.x11.xyz/cgi/">
Require all granted
Options +ExecCGI
AddHandler cgi-script .cgi
</Directory>
#______________________________________________________________
# 1.3. Restart Apache
sudo systemctl reload apache2
# 2.1. Prepare the cgi
sudo nano /var/www/test1.x11.xyz/cgi/simple.cgi
# Remember to include the line #/usr/bin/env python3
#_________________________________________________________________
#!/usr/bin/env python3
print("Content-type: text/html\n\n")
print("<html><head><title>Environments Test</title></head><body>")
print("Hello CGI\n")
print("</body></html>")
#_________________________________________________________________
#
# 2.2. Make it executable (You are going to have to do that for all of your scripts)
sudo chmod 775 /var/www/test1.x11.xyz/cgi/simple.cgi
#
# 2.3. Test the CGI
http://tes1.karasite.com/cgi/simple.cgi
3. Another Python script for printing environment values
# 3.1. Prepare the CGI
sudo nano /var/www/test1.x11.xyz/cgi/envtest.cgi
#_________________________________________________________________
#!/usr/bin/env python3
import os
print("Content-type: text/html\n\n")
print("<html><head><title>Environments Test</title></head><body>")
print("<h2>Environment:</h2>")
for keyval in os.environ.keys():
print(f"<p><b>{keyval}:</b> {os.environ[keyval]}</p>")
print("</body></html>")
#_________________________________________________________________
#
# 3.2. Make it executable
sudo chmod 775 /var/www/test1.x11.xyz/cgi/envtest.cgi
#
# 3.3. Test your python CGI
http://test1.x11.xyz/cgi/envtest.cgi
4. An example with a form with text and textarea fields
# a script to process it
# 4.1. Prepare the html page
sudo nano /var/www/test1.x11.xyz/formtext.html
#________________________________________________________________
<html> <title>Form With Text Fields</title>
<body> <h1>Form With Text Fields</h1>
<form action = "/cgi/formtext.cgi" method = "post"/>
Name: <input type="text" name="name">
Surname: <input type="text" name="surname"/>
Age: <input type="text" name="age">
<br><br><textarea name = "details" cols = "80" rows = "4">
Enter details here...
</textarea><br>
<input type = "submit" value = "Submit"/>
</form>
</body> </html>
#________________________________________________________________
#
# 4.2. Prepare the CGI
sudo nano /var/www/test1.x11.xyz/cgi/formtext.cgi
#________________________________________________________________
#!/usr/bin/env python3
import cgi
form = cgi.FieldStorage()
# Fill data from html fields
# Get data from fields
name = form.getvalue('name')
surname = form.getvalue('surname')
age = form.getvalue('age')
if form.getvalue('details'):
details = form.getvalue('details')
else:
details = "Not entered"
print("Content-type:text/html\r\n\r\n")
print("<html> <head> <title>Form Text Fields</title>")
print("</head> <body>")
print(f"{name} {surname} is {age} years old")
print(f"<br>Details:<br> {details}")
print("</body> </html>")
#________________________________________________________________
#
# 4.3. Make it executable
sudo chmod 775 /var/www/test1.x11.xyz/cgi/formtext.cgi
#
# 4.4. Test your python CGI
http://test1.x11.xyz/cgi/formtext.html
5. Checkbox, Radio Button and Dropdown Box
# 5.1. Prepare the html page
sudo nano /var/www/test1.x11.xyz/checkradio.html
#________________________________________________________________
<html> <title>Form With Checkbox, Radio Button, and Dropdown Box</title>
<body> <h1>Form With Checkboxes, Radio Button and Dropdown Box</h1>
<form action = "/cgi/checkradio.cgi" method = "POST" target = "_blank">
<br>Primary Subjects:<br>
<input type = "checkbox" name = "maths" value = "on" /> Maths
<input type = "checkbox" name = "physics" value = "on" /> Physics
<br><br>
Secondary Subject:<br>
<input type = "radio" name = "subject" value = "sociology" /> Sociology
<input type = "radio" name = "subject" value = "pyscology" /> Pyscology
<br><br>
Language:
<select name = "dropdown">
<option value = "English" selected>English</option>
<option value = "Spanish">Spanish</option>
<option value = "Turkish">Turkish</option>
</select>
<input type = "submit" value = "Select Subjects" />
</form>
</body> </html>
#________________________________________________________________
#
# 5.2. Prepare the CGI
sudo nano /var/www/test1.x11.xyz/cgi/checkradio.cgi
#________________________________________________________________
#!/usr/bin/env python3
# Import modules for CGI handling
import cgi, cgitb
# Create instance of FieldStorage
form = cgi.FieldStorage()
# Get data from fields
if form.getvalue('maths'):
math_flag = "ON"
else:
math_flag = "OFF"
if form.getvalue('physics'):
physics_flag = "ON"
else:
physics_flag = "OFF"
if form.getvalue('subject'):
subject = form.getvalue('subject')
else:
subject = "Not set"
if form.getvalue('dropdown'):
language = form.getvalue('dropdown')
else:
language = "Not entered"
print("Content-type:text/html\r\n\r\n")
print("<html>")
print("<head>")
print("<title>Checkbox - Radio Button CGI Program</title>")
print("</head>")
print("<body>")
print("Primary Subject(s):<br>")
print(f"Math is : {math_flag}<br>")
print(f"Physics is: {physics_flag}<br><br>")
print(f"Secondary Subject: {subject}<br><br>")
print(f"Language: {language}")
print("</body> </html>")
#________________________________________________________________
#
# 5.3. Make it executable
sudo chmod 775 /var/www/test1.x11.xyz/cgi/checkradio.cgi
#
# 5.4. Test your python CGI
http://test1.x11.xyz/checkradio.html
# Code for setting cookies are sent just before the Content-type line
# 6.1. Prepare cgi file
sudo nano /var/www/test1.x11.xyz/cgi/setcookies.cgi
#________________________________________________________________
#!/usr/bin/env python3
# Cookies for the current directory
print('Set-Cookie:Field1="Value1"')
print('Set-Cookie:Field2="Value2"; Expires="Mon, 09 Mar 2021 08:13:24 GMT"')
print('Set-Cookie:Field3="Value3"; Max-Age=10000000') # Seconds
# Cookies for the root directory
print('Set-Cookie:Field4="Value4"; Path=/')
print('Set-Cookie:Field5="Value5"; Path=/; Expires="Mon, 09 Mar 2021 08:13:24 GMT"')
print('Set-Cookie:Field6="Value6"; Path=/; Max-Age=10000000') # Seconds
# HTML page
print("Content-type:text/html\r\n\r\n")
print("<html><head><title>Cookie Test</title></head><body>")
print("All cookies are set\n")
print("</body></html>")
#________________________________________________________________
#
# 6.2. Make your script executable
sudo chmod 775 /var/www/test1.x11.xyz/cgi/setcookies.cgi
#
# 6.3. Test your python CGI
http://test1.x11.xyz/setcookies.cgi
#
# Code for retrieving cookies
# 7.1. Prepare cgi file
sudo nano /var/www/test1.x11.xyz/cgi/getcookies.cgi
#________________________________________________________________
#!/usr/bin/env python3
from os import environ
import cgi, cgitb
print("Content-type:text/html\r\n\r\n")
print("<html><head><title>Retrieving Cookies</title></head><body>")
print("<br>Retrieving Cookies<br>")
if 'HTTP_COOKIE' in environ:
print("in if")
cookiesline = environ['HTTP_COOKIE']
cookies = cookiesline.split(";")
for cookie in cookies:
key, value = cookie.split("=")
print(f"Key = {key}, Value={value} <br>")
else:
print("No cookies found")
print("</body></html>")
#________________________________________________________________
#
# 7.2. Make your script executable
sudo chmod 775 /var/www/test1.x11.xyz/cgi/getcookies.cgi
#
# 7.3. Test your python CGI
http://test1.x11.xyz/cgi/getcookies.cgi
#