CGI::Fast(3pm) User Contributed Perl Documentation CGI::Fast(3pm)
NAME
CGI::Fast - CGI Interface for Fast CGI
SYNOPSIS
use CGI::Fast
socket_path => '9000',
socket_perm => 0777,
listen_queue => 50;
use CGI qw/ :standard /;
$COUNTER = 0;
# optional, will default to STDOUT, STDERR
CGI::Fast->file_handles({
fcgi_output_file_handle => IO::Handle->new,
fcgi_error_file_handle => IO::Handle->new,
});
while ($q = CGI::Fast->new) {
process_request($q);
}
DESCRIPTION
CGI::Fast is a subclass of the CGI object created by CGI.pm. It is
specialized to work with the FCGI module, which greatly speeds up CGI
scripts by turning them into persistently running server processes.
Scripts that perform time-consuming initialization processes, such as
loading large modules or opening persistent database connections, will
see large performance improvements.
Note that as CGI::Fast is based on CGI.pm it is no longer advised as a
way to write Perl web apps. See
<https://metacpan.org/pod/CGI#CGI.pm-HAS-BEEN-REMOVED-FROM-THE-PERL-CORE>
for more information about this
OTHER PIECES OF THE PUZZLE
In order to use CGI::Fast you'll need the FCGI module. See
http://www.cpan.org/ for details.
WRITING FASTCGI PERL SCRIPTS
FastCGI scripts are persistent: one or more copies of the script are
started up when the server initializes, and stay around until the server
exits or they die a natural death. After performing whatever one-time
initialization it needs, the script enters a loop waiting for incoming
connections, processing the request, and waiting some more.
A typical FastCGI script will look like this:
#!perl
use CGI::Fast;
do_some_initialization();
while ($q = CGI::Fast->new) {
process_request($q);
}
Each time there's a new request, CGI::Fast returns a CGI object to your
loop. The rest of the time your script waits in the call to new().
When the server requests that your script be terminated, new() will
return undef. You can of course exit earlier if you choose. A new
version of the script will be respawned to take its place (this may be
necessary in order to avoid Perl memory leaks in long-running scripts).
CGI.pm's default CGI object mode also works. Just modify the loop this
way:
while (CGI::Fast->new) {
process_request();
}
Calls to header(), start_form(), etc. will all operate on the current
request.
INSTALLING FASTCGI SCRIPTS
See the FastCGI developer's kit documentation for full details. On the
Apache server, the following line must be added to srm.conf:
AddType application/x-httpd-fcgi .fcgi
FastCGI scripts must end in the extension .fcgi. For each script you
install, you must add something like the following to srm.conf:
FastCgiServer /usr/lib/cgi-bin/file_upload.fcgi -processes 2
This instructs Apache to launch two copies of file_upload.fcgi at
startup time.
USING FASTCGI SCRIPTS AS CGI SCRIPTS
Any script that works correctly as a FastCGI script will also work
correctly when installed as a vanilla CGI script. However it will not
see any performance benefit.
EXTERNAL FASTCGI SERVER INVOCATION
FastCGI supports a TCP/IP transport mechanism which allows FastCGI
scripts to run external to the webserver, perhaps on a remote machine.
To configure the webserver to connect to an external FastCGI server, you
would add the following to your srm.conf:
FastCgiExternalServer /usr/lib/cgi-bin/file_upload.fcgi -host sputnik:8888
Two environment variables affect how the "CGI::Fast" object is created,
allowing "CGI::Fast" to be used as an external FastCGI server. (See
"FCGI" documentation for "FCGI::OpenSocket" for more information.)
You can set these as ENV variables or imports in the use CGI::Fast
statement. If the ENV variables are set then these will be favoured so
you can override the import statements on the command line, etc.
FCGI_SOCKET_PATH / socket_path
The address (TCP/IP) or path (UNIX Domain) of the socket the
external FastCGI script to which bind an listen for incoming
connections from the web server.
FCGI_SOCKET_PERM / socket_perm
Permissions for UNIX Domain socket.
FCGI_LISTEN_QUEUE / listen_queue
Maximum length of the queue of pending connections, defaults to 100.
For example:
use CGI::Fast
socket_path => "sputnik:8888",
listen_queue => "50"
;
use CGI qw/ :standard /;
do_some_initialization();
while ($q = CGI::Fast->new) {
process_request($q);
}
Or:
use CGI::Fast;
use CGI qw/ :standard /;
do_some_initialization();
$ENV{FCGI_SOCKET_PATH} = "sputnik:8888";
$ENV{FCGI_LISTEN_QUEUE} = 50;
while ($q = CGI::Fast->new) {
process_request($q);
}
Note the importance of having use CGI after use CGI::Fast as this will
prevent any CGI import pragmas being overwritten by CGI::Fast. You can
use CGI::Fast as a drop in replacement like so:
use CGI::Fast qw/ :standard /
FILE HANDLES
FCGI defaults to using STDOUT and STDERR as its output filehandles -
this may lead to unexpected redirect of output if you migrate scripts
from CGI.pm to CGI::Fast. To get around this you can use the
file_handles method, which you must do before the first call to
CGI::Fast->new. For example using IO::Handle:
CGI::Fast->file_handles({
fcgi_output_file_handle => IO::Handle->new,
fcgi_error_file_handle => IO::Handle->new,
});
while (CGI::Fast->new) {
..
}
Overriding STDIN using the "fcgi_input_file_handle" key is also
possible, however doing so is likely to break at least POST requests.
CAVEATS
I haven't tested this very much.
LICENSE
Copyright 1996-1998, Lincoln D. Stein. All rights reserved. Currently
maintained by Lee Johnson
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
BUGS
Address bug reports and comments to:
https://github.com/leejo/cgi-fast
SEE ALSO
CGI::Carp, CGI
perl v5.36.0 2023-11-17 CGI::Fast(3pm)
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