Common Gateway Interface
<World-Wide Web> (CGI) A standard
for running external programs from a World-Wide Web HTTP server
CGI specifies how to pass arguments to the executing program as part of the HTTP request.
It also defines a set of environment variables.
Commonly, the program will generate some HTML
which will be passed back to the browser
but it can also request URL redirection
CGI allows the returned HTML (or other document type) to depend in any arbitrary way on the request.
The CGI program can, for example, access information in a database
and format the results as HTML.
A CGI program can be any program which can accept command line arguments.
is a common choice for writing CGI scripts.
Some HTTP servers require CGI programs to reside in a special directory, often "/cgi-bin" but better servers provide ways to distinguish CGI programs so they can be kept in the same directories as the HTML files to which they are related.
Whenever the server receives a CGI execution request it creates a new process to run the external program.
If the process fails to terminate for some reason, or if requests are received faster than the server can respond to them, the server may become swamped with processes.
In order to improve performance, Netscape
developed the ISAPI
standard which allow CGI-like tasks to run as part of the main server process, thus avoiding the overhead of creating a new process to handle each CGI invocation.
Current version: 1.1.