[dancer-users] passing client/socket error from server to dancer app

[Paul Clements]

Never mind...figured it out. I'm seeing a SIGPIPE now when the client
disconnects.

Sorry for the noise...

On Sat, Feb 13, 2021 at 9:43 AM Paul Clements <paul.clements at us.sios.com> wrote:
>
> I asked a similar question a few weeks ago, and am circling back
> because I am still in need of a solution. As it turns out, without a
> way to handle client/socket disconnect, I am having trouble finding a
> suitable working combination of Dancer2/PSGI Server. I've tried
> several, and while Twiggy does give an error (SIGPIPE) on client
> disconnect, my app is not AnyEvent- (or even thread-) based, so the
> forking servers (e.g., Starman) are a better fit (without rewriting
> substantial amounts of code).
>
> At this point, I'm wondering if a fairly simple change to Dancer2
> might be acceptable. It's a minimal change, but gives the Dancer2 app
> a way to know when a client disconnect has occurred in a "delayed"
> handler.
>
> Specifically, it turns out that many/most servers return "undef" from
> their write routines once the socket is closed. So, the idea is to
> allow that information to pass back to the app:
>
> diff --git a/lib/Dancer2/Core/DSL.pm b/lib/Dancer2/Core/DSL.pm
> index fd29ac74..9adb3e28 100644
> --- a/lib/Dancer2/Core/DSL.pm
> +++ b/lib/Dancer2/Core/DSL.pm
> @@ -329,7 +329,7 @@ sub content {
>
>      eval {
>          $Dancer2::Core::Route::WRITER->write(@_);
> -        1;
> +        # use write's return code instead # 1;
>      } or do {
>          my $error = $@ || 'Zombie Error';
>          $Dancer2::Core::Route::ERROR_HANDLER
>
> It doesn't seem like the constant 1 return code from "content" is
> something that anyone would be relying on, so changing it shouldn't
> hurt (?), but would provide a way to get the error information back to
> the app, e.g.:
>
> my $client_ok = content $data;
> if (!defined($client_ok)) { # something's wrong!
>
> Thanks,
> Paul