Introduction
LiteSpeed SAPI is a protocol designed specifically
for communication between LiteSpeed web server and third
party web application that runs in it own process.
Like FastCGI Application, Application utilize LiteSpeed SAPI will
run in it own persistent process, and talk to web server via a persistent
socket connection. The overhead of starting a new process or socket
connection has been complete avoided.
LiteSpeed SAPI is designed to be the fastest server
API for inter-process communication between LiteSpeed Web Server
and third party web application, protocol overhead has been
reduced to minimum. Comparing to FastCGI protocol, LiteSpeed
SAPI has about 25% speed advantage over FastCGI for simple
"Hello World" application.
Does not like some server API which allow you to embed
your module inside the web server process, LiteSpeed SAPI application
run in its own process and talk to web server through a socket connection.
The main benefit of doing this is better reliability and security, a buggy
application will not able to crash the whole web server or affect other
application. Applications can be started with different user
IDs (usually called "suEXEC"), file system can be easily secured.
In theory, out of process application is not as fast as embedded modules,
however, due to the highly optimized protocol, our benchmark shows that
LSAPI application delivers better performance than Apache modules for
dynamic content generation.
An API library written in C is available for building
third party web application using LiteSpeed SAPI. The protocol
detail will be published later. Currently, we have the following LSAPI
modules for third party scripting languages:
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