
The Web server is now an application server because it serves both files
and applications. The standard API for a Web server is the Common
Gateway Interface or CGI. Applications that need to interface with the
server must follow CGI.
CGI is a very simple API. It specifies how the Web server invokes the appli-
cation, how it passes the parameters it received from the user, and how the
application must return the page.
CGI is a very popular interface that is supported by all the major Web
servers. However, CGI has proven to be relatively inefficient. In particular,
with CGI, the Web server must invoke a new instance of the application for
each request. ...