linux man page for dbd::gofer::transport::corostream

DBD::Gofer::Transport::corostream(3pm)			User Contributed Perl Documentation		    DBD::Gofer::Transport::corostream(3pm)

NAME
       DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent

SYNOPSIS
	  DBI_AUTOPROXY="dbi:Gofer:transport=corostream" perl some-perl-script-using-dbi.pl

       or

	  $dsn = ...; # the DSN for the driver and database you want to use
	  $dbh = DBI->connect("dbi:Gofer:transport=corostream;dsn=$dsn", ...);

DESCRIPTION
       The BIG WIN from using Coro is that it enables the use of existing DBI frameworks like DBIx::Class.

KNOWN ISSUES AND LIMITATIONS
	 - Uses Coro::Select so alters CORE::select globally
	   Parent class probably needs refactoring to enable a more encapsulated approach.

	 - Doesn't prevent multiple concurrent requests
	   Probably just needs a per-connection semaphore

	 - Coro has many caveats. Caveat emptor.

STATUS
       THIS IS CURRENTLY JUST A PROOF-OF-CONCEPT IMPLEMENTATION FOR EXPERIMENTATION.

       Please note that I have no plans to develop this code further myself.  I'd very much welcome contributions. Interested? Let me know!

AUTHOR
       Tim Bunce, <http://www.tim.bunce.name>

LICENCE AND COPYRIGHT
       Copyright (c) 2010, Tim Bunce, Ireland. All rights reserved.

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

SEE ALSO
       DBD::Gofer::Transport::stream

       DBD::Gofer

APPENDIX
       Example code:

	   #!perl

	   use strict;
	   use warnings;
	   use Time::HiRes qw(time);

	   BEGIN { $ENV{PERL_ANYEVENT_STRICT} = 1; $ENV{PERL_ANYEVENT_VERBOSE} = 1; }

	   use AnyEvent;

	   BEGIN { $ENV{DBI_TRACE} = 0; $ENV{DBI_GOFER_TRACE} = 0; $ENV{DBD_GOFER_TRACE} = 0; };

	   use DBI;

	   $ENV{DBI_AUTOPROXY} = 'dbi:Gofer:transport=corostream';

	   my $ticker = AnyEvent->timer( after => 0, interval => 0.1, cb => sub {
	       warn sprintf "-tick- %.2f
", time
	   } );

	   warn "connecting...
";
	   my $dbh = DBI->connect("dbi:NullP:");
	   warn "...connected
";

	   for (1..3) {
	       warn "entering DBI...
";
	       $dbh->do("sleep 0.3"); # pseudo-sql understood by the DBD::NullP driver
	       warn "...returned
";
	   }

	   warn "done.";

       Example output:

	   $ perl corogofer.pl
	   connecting...
	   -tick- 1293631437.14
	   -tick- 1293631437.14
	   ...connected
	   entering DBI...
	   -tick- 1293631437.25
	   -tick- 1293631437.35
	   -tick- 1293631437.45
	   -tick- 1293631437.55
	   ...returned
	   entering DBI...
	   -tick- 1293631437.66
	   -tick- 1293631437.76
	   -tick- 1293631437.86
	   ...returned
	   entering DBI...
	   -tick- 1293631437.96
	   -tick- 1293631438.06
	   -tick- 1293631438.16
	   ...returned
	   done. at corogofer.pl line 39.

       You can see that the timer callback is firing while the code 'waits' inside the do() method for the response from the database. Normally
       that would block.

perl v5.12.3							    2010-12-29				    DBD::Gofer::Transport::corostream(3pm)