[Catalyst] Non Blocking File Streaming - write_fh

[neil.lunn]

On 7/12/2013 7:37 AM, John Napiorkowski wrote:
> Neil,
>
> You're the man!  Any change I could get this as a pull request on the git=
hub repo (is also the sane place I am asking people to submit articles)
>
>
> https://github.com/perl-catalyst/2013-Advent-Staging

Sure. sending pull req now.
>
> That way I am sure to get the code correct.
>
> The only thing is that when using eval I prefer the following idiom as I =
think its a little safer
>
> eval { ...; 1 } || die "trouble: $!";
>
> On the other hand since Catalyst already requires Try::Tiny no reason to =
just not use that.

Missed that. But interestingly this does not seem to import in this context.

Also noted that this is just happening under Twiggy. This code seems to =

be responsible:

package Twiggy::Writer;
use AnyEvent::Handle;
sub new {
my ( $class, $socket, $exit ) =3D @_;
bless { handle =3D> AnyEvent::Handle->new( fh =3D> $socket ), exit_guard =
=3D> =

$exit }, $class;
}


Twiggy seems to be aware that the output socket has been closed where =

some other server implementations do
not. Have had this problem before.

Strange IO::Handle in response body code there also MyApp-FunnyIO

Neil

>
> John
>
>
>
> On Friday, December 6, 2013 1:56 AM, neil.lunn <neil at mylunn.id.au> wrote:
>
> Hi all, and mostly John,
>
> I was just browsing through the upcoming Advent code examples when I saw
> the example for this had a bug. The code will die horribly when a call
> is made to HEAD rather than get as the output filehandle gets closed.
> The die is from an uncaught exception on $self->write.
>
> My patch to MyApp::Stream :
>
> sub read_chunk {
>     my ($self, $fh, $offset) =3D @_;
>     my $buffer =3D '';
>     aio_read $fh, $offset, 65536, $buffer, 0, sub {
>       my $status =3D shift;
>       die "read error[$status]: $!" unless $status >=3D 0;
>       if($status) {
>         eval {
>           $self->write($buffer);
>         };
>         if ($@) {
>           warn "Cannot write, probably a closed pipe";
>         }
>         $self->read_chunk($fh, ($offset + 65536));
>       } else {
>         $self->close;
>         aio_close $fh, sub { };
>       }
>     }
> }
>
> So the eval block and the warn, not die as this is not being caught
> under any other exception handler. Real world, YMMV. Not elegant, but
> would probably be better for passing in context.
>
> Also I have a full Advent style writeup of the issue Bill brought up
> recently with explainations and solutions down to making the handle DWIW
> for for transparent handing over to Catalyst. If that is wanted/needed :)
>
> Neil
>
>
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