Run Python as a CGI Script
IONOS editorial team3 mins
There are several ways to use Python to create a web application, or generate web content. In this tutorial we will cover the simplest and most basic form of viewing the output of a Python script in a browser.
In some situations, running Python as a CGI script may be a good option:
- The script is small and lightweight.
- You are just starting out learning Python, and want to start with a simple solution.
- You only need to do the most basic level of testing in a browser.
There are several better and more robust alternatives to running a Python script as a CGI script. Based on your needs, we recommend either using Apache's mod_wsgi, or installing a Python web framework like CherryPy.
Requirements
- A Cloud Server with Apache configured to allow CGI scripts.
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Run Python as a CGI Script
After verifying that your server is configured to allow CGI scripts, you can upload the Python script to your designated cgi-bin directory.
- CentOS 7: The default CGI directory is var/www/cgi-bin/
- Ubuntu 16.04: The default CGI directory is /usr/lib/cgi-bin
Give the file executable permissions:
CentOS 7:
sudo chmod 755 /var/www/cgi-bin/example.cgiUbuntu 16.04:
sudo chmod 755 /usr/lib/cgi-bin/example.cgiYou can now view the script in a browser, using either the domain name or IP address:
http://example.com/cgi-bin/example.cgi
http://192.168.0.1/cgi-bin/example.cgiFile Extensions
To run your Python script as a CGI script, you can either:
- Name your script with a .cgi file extension (example.cgi).
- Configure Apache to recognize and allow the .py file extension as a CGI script.
To add the .py configuration to Apache, edit the Apache configuration file. On Ubuntu 16.04, this is already set by default. You will not need to make any changes to run a .py file as a CGI script.
On CentOS 7, open the httpd.conf file for editing:
sudo nano /etc/httpd/conf/httpd.confFind this section:
#
#
Directory "/var/www/cgi-bin"
AllowOverride None
Options +ExecCGI
AddHandler cgi-script .cgi .pl
Require all granted
/DirectoryAdd .py to the AddHandler configuration:
#
#
Directory "/var/www/cgi-bin"
AllowOverride None
Options +ExecCGI
AddHandler cgi-script .cgi .pl .py
Require all granted
DirectorySave and exit the file. Then restart Apache so that the changes take effect:
sudo systemctl restart httpdTroubleshooting
For testing purposes, we recommend you use the following example script:
#!/usr/bin/env python
print "Content-Type: text/html"
print
print ;h1 Hello world./h1'Save this as example.py and upload it to your server's designated cgi-bin directory for testing. Then view the script in a browser, using either the domain name or IP address:
http://example.com/cgi-bin/example.py
http://192.168.0.1/cgi-bin/example.pyYou will see "Hello world."
404 error: This means that the file cannot be found at the URL you specified. Be sure that the script is in the right directory.
- CentOS 7: The default CGI directory is var/www/cgi-bin/
- Ubuntu 16.04: The default CGI directory is /usr/lib/cgi-bin
Server 500 error: This usually indicates that the file's permissions are wrong. Be sure the script has executable (chmod 755) permissions:
jdoe@localhost:/etc/apache2# ll /usr/lib/cgi-bin/test.cgi
rwxr-xr-x 1 jdoe jdoe 85 Jul 22 16:53 /usr/lib/cgi-bin/test.cgi*The correct permissions for the file are rwxr-xr-x. If not, give the file executable permissions:
CentOS 7:
sudo chmod 755 /var/www/cgi-bin/example.cgiUbuntu 16.04:
sudo chmod 755 /usr/lib/cgi-bin/example.cgi- Simple registration
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