PSGI file evaluation convention

[miyagawa]

https://github.com/plack/psgi-specs/wiki/PSGI-file-evaluation-convention

Attach your feedbacks to this issue.

[dolmen]

I load my PSGI apps with "require" instead of "eval do". "require" returns the result of last expression of the file, so that works well.

This allow me to make a clean package for the application, with a known namespace, and so I can distribute the application as a CPAN distribution. Also, "require" use @inc to find the file.

Here is an example: https://metacpan.org/source/DOLMEN/Pod-POM-Web-PSGI-0.002/lib/Pod/POM/Web/PSGI.pm (have a look at the code AND the POD).

[miyagawa]

Yes, I like it, but one problem with require is that you can't instantiate the same application twice, which means it gets moot when the module is preloaded somehow, or when you want to instantiate the app per children in a forked environment.

my $app1 = require MyApp::PSGI;
mu $app2 = require MyApp::PSGI; # doesn't work

[miyagawa]

This convention doesn't prevent you from loading your app with require though - this is more lower level discussion that happens in the web server when given a path to the .psgi file. You can always do require MyApp inside .psgi, like you can currently do.

Whether your app/framework gives the PSGI code refs with require (as in the return value of the .pm) or ->psgi_app or sub { MyApp->run_psgi } or anything else, is out of the scope.