DBD::Gofer::Transport::corostreUserpContributed Perl DocumeDBD::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\n", time
           } );

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

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

           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 v5.20.0                                2013-04-04     DBD::Gofer::Transport::corostream(3pm)