# NAME

CGI::Fast - CGI Interface for Fast CGI

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# 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](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/etc/httpd/fcgi-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/etc/httpd/fcgi-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.

Address bug reports and comments to:

    https://github.com/leejo/cgi-fast

# BUGS

This section intentionally left blank.

# SEE ALSO

[CGI::Carp](https://metacpan.org/pod/CGI::Carp), [CGI](https://metacpan.org/pod/CGI)