Running a Python Application with LSAPI

LiteSpeed SAPI is the easiest and fastest way to run web applications with LiteSpeed Web Server. Recently, we've introduced LSAPI support for Python applications through WSGI. WSGI (Web Server Gateway Interface) is a low-level interface between web servers and web applications. It allows Python applications designed for WSGI to be used in a variety of settings. It is important to note that, while most Python applications are WSGI-compatible, not all are.

This wiki will go over how to set up LSWS to run Python applications with LWSGI. This wiki assumes that you already have a working version of Python installed and virtual hosts set up to run it on.

The module can be downloaded from our site here.

I have downloaded the module to my server root /usr/local/lsws. To recompile Python, I go into the module directory and run the following commands:

cd /usr/local/lsws/wsgi-lsapi-1.0
python ./configure.py
make

I then copy the file lswsgi to /usr/local/lsws/fcgi-bin/. (This directory is where all your LSAPI executables go.)

cp lswsgi /usr/local/lsws/fcgi-bin/

Now my LSWSGI executable is ready for LiteSpeed Web Server.

This process is the same as with any other LSAPI application, except with a different executable and suffix.

I go to the External App tab (WebAdmin console > Configuration > External App) and add an external application. (This can be done at the server or virtual host level.)

I make the type LSAPI App.

I give it a name and a socket. Most importantly, for the Command setting, I specify the location of my lswsgi executable: /usr/local/lsws/fcgi-bin/lswsgi. (You also have to pick values for Max Connections, Initial Request Timeout, and Retry Timeout.)

Now I have an LSWSGI external application.

Now I need to create a WSGI script handler to tell LSWS to send .wsgi scripts to my LSWSGI application. I go to the Script Handler tab (WebAdmin console > Configuration > Script Handler) and click Add. (This, also, can be done at the server or virtual host level.)

I stipulate wsgi as the suffix of my WSGI Python apps. I pick Handler Type LiteSpeed SAPI and, for Handler Name, choose the LSWSGI external application I just created. (If you want scripts other than .wsgi to use Python, you can make extra script handlers to handle those scripts.)

Now my LSWS can handle .wsgi scripts and knows where to send them.

To test this I'm using the simple hello world script below:

def application(environ, start_response):
  start_response('200 OK', [('Content-Type', 'text/plain')])
  return ['Hello World!\n']

I name my file hello.wsgi and save it to /usr/local/lsws/DEFAULT/html. This is the document root for LSWS's default vhost, Example.

Now, when I point my browser to localhost:8088/hello.wsgi, I see the correct output displayed. It works!