NAME
FCGI::EV - Implement FastCGI protocol for use in EV-based applications
VERSION
This document describes FCGI::EV version v2.0.1
SYNOPSIS
use FCGI::EV;
use Some::FCGI::EV::Handler;
# while in EV::loop, accept incoming connection from web server into
# $sock, then start handling FastCGI protocol on that connection,
# using Some::FCGI::EV::Handler for processing CGI requests:
FCGI::EV->new($sock, 'Some::FCGI::EV::Handler');
#
# EXAMPLE: complete FastCGI server (without error handling code)
# use FCGI::EV::Std handler (download separately from CPAN)
#
use Socket;
use Fcntl;
use EV;
use FCGI::EV;
use FCGI::EV::Std;
my $path = '/tmp/fastcgi.sock';
socket my $srvsock, AF_UNIX, SOCK_STREAM, 0;
unlink $path;
my $umask = umask 0; # ensure 0777 perms for unix socket
bind $srvsock, sockaddr_un($path);
umask $umask;
listen $srvsock, SOMAXCONN;
fcntl $srvsock, F_SETFL, O_NONBLOCK;
my $w = EV::io $srvsock, EV::READ, sub {
accept my($sock), $srvsock;
fcntl $sock, F_SETFL, O_NONBLOCK;
FCGI::EV->new($sock, 'FCGI::EV::Std');
};
EV::loop;
DESCRIPTION
This module implement FastCGI protocol for use in EV-based
applications. (That mean you have to run EV::loop in your application
or this module will not work.)
It receive and parse data from web server, pack and send data to web
server, but it doesn't process CGI requests received from web server -
instead it delegate this work to another module called 'handler'. For
one example of such handler, see FCGI::EV::Std.
FCGI::EV work using non-blocking sockets and initially was designed to
use in event-based CGI applications (which able to handle multiple
parallel CGI requests in single process without threads/fork). This
require from CGI to avoid any operations which may block, like using
SQL database - instead CGI should delegate all such tasks to remote
services and talk to these services in non-blocking mode.
It also possible to use it to run usual CGI.pm-based applications. If
you will do this using FCGI::EV::Std handler, then only one CGI request
will be executed at a time (which is probably not what you expect from
FastCGI!), because FCGI::EV::Std doesn't implement any process-manager.
But it's possible to develop another handlers for FCGI::EV, which will
support process-management and so will handle multiple CGI request in
parallel.
This module doesn't require from user to use CGI.pm - any module for
parsing CGI params can be used in general (details depends on used
FCGI::EV handler module).
INTERFACE
new
FCGI::EV->new( $sock, $class );
Start talking FastCGI protocol on $sock (which should be socket open to
just-connected web server), and use $class to handle received CGI
requests.
Module $class should implement "FCGI::EV handler" interface. You can
use either FCGI::EV::Std from CPAN or develop your own.
Return nothing. (Created FCGI::EV object will work in background and
will be automatically destroyed after finishing I/O with web server.)
HANDLER CLASS INTERFACE
Handler class (which name provided in $class parameter to
FCGI::EV->new()) must implement this interface:
new( $server, \%env )
When FCGI::EV object receive initial part of CGI request (environment
variables) it will call $handler_class->new() to create handler
object which should process that CGI request.
Parameter $server is FCGI::EV object itself. It's required to send
CGI reply. WARNING! Handler may keep only weaken() reference to
$server!
After calling new() FCGI::EV object ($server) will continue receiving
STDIN content from web server and will call $handler->stdin() each
time it get next part of STDIN.
stdin( $data, $is_eof )
The $data is next chunk of STDIN received from web server. Flag
$is_eof will be true if $data was last part of STDIN.
Usually handler shouldn't begin processing CGI request until all
content of STDIN will be received.
DESTROY
This method is optional. It will be called when connection to web
server is closed and FCGI::EV object going to die (but it's still
exists when DESTROY is called - except if DESTROY was called while
global destruction stage).
Handler object may use DESTROY to interrupt current CGI request if
web server close connection before CGI send it reply.
SENDING CGI REPLY
After handler got %env (in new()) and complete STDIN (in one or more
calls of stdin()) it may start handling this CGI request and prepare
reply to send to web server. To send this data it should use method
$server->stdout(), where $server is object given to new() while
creating handler object (it should keep weak reference to $server
inside to be able to reply).
stdout( $data, $is_eof )
CGI may send reply in one or more parts. Last part should have
$is_eof set to true. DESTROY method of handler object will be called
shortly after handler object will do $server->stdout( $data, 1 ).
HANDLER EXAMPLE
This handler will process CGI requests one-by-one (i.e. in blocking
mode). On request function main::main() will be executed. That function
may use standard CGI.pm module to get request parameters and send it
reply using usual print to STDOUT.
There no error-handling code in this example, see FCGI::EV::Std for
more details.
package FCGI::EV::ExampleHandler;
use Scalar::Util qw( weaken );
use CGI::Stateless; # needed to re-init CGI.pm state between requests
sub new {
my ($class, $server, $env) = @_;
my $self = bless {
server => $server,
env => $env,
stdin => q{},
}, $class;
weaken($self->{server});
return $self;
}
sub stdin {
my ($self, $stdin, $is_eof) = @_;
$self->{stdin} .= $stdin;
if ($is_eof) {
local *STDIN;
open STDIN, '<', \$self->{stdin};
local %ENV = %{ $self->{env} };
local $CGI::Q = CGI::Stateless->new();
local *STDOUT;
my $reply = q{};
open STDOUT, '>', \$reply;
main::main();
$self->{server}->stdout($reply, 1);
}
return;
}
DIAGNOSTICS
There no errors returned in any way by this module, but there few
warning messages may be printed:
FCGI::EV: IO: %s
While doing I/O with web server error %s happened and connection was
closed.
FCGI::EV: %s
While parsing data from web server error %s happened and connection
was closed. (That error probably mean bug either in web server or
this module.)
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through the issue tracker at
https://github.com/powerman/perl-FCGI-EV/issues. You will be notified
automatically of any progress on your issue.
Source Code
This is open source software. The code repository is available for
public review and contribution under the terms of the license. Feel
free to fork the repository and submit pull requests.
https://github.com/powerman/perl-FCGI-EV
git clone https://github.com/powerman/perl-FCGI-EV.git
Resources
* MetaCPAN Search
https://metacpan.org/search?q=FCGI-EV
* CPAN Ratings
http://cpanratings.perl.org/dist/FCGI-EV
* AnnoCPAN: Annotated CPAN documentation
http://annocpan.org/dist/FCGI-EV
* CPAN Testers Matrix
http://matrix.cpantesters.org/?dist=FCGI-EV
* CPANTS: A CPAN Testing Service (Kwalitee)
http://cpants.cpanauthors.org/dist/FCGI-EV
AUTHOR
Alex Efros <powerman@cpan.org>
COPYRIGHT AND LICENSE
This software is Copyright (c) 2009- by Alex Efros <powerman@cpan.org>.
This is free software, licensed under:
The MIT (X11) License