A begine's naive question, please help

[onsosb]

I have a fairly complex perl code that runs in batch mode, command line. I need to build a simple web app to run the code and display the output. The program, in the command line mode takes as input a text file utf8 encoding, some optional arguments and displays the output or writes it to a file.
example: perl ./my appl.pl -input= input.txt > result.txt
The idea is the web version either gets the file name or reads the input text from a text field, passes the info to the perl code and writes out the out put file and also displays the result in a text field
Any comments, codes, etc is truly appreciated. I really need lots of hand holding
Thanks
Bid

[s1037989]

See the cookbook for subprocesses. You'll need to play around with what you need for the inputs. Everything you should need to be successful with this should be covered by the Tutorial Guide.

use Mojolicious::Lite -signatures;
use Mojo::IOLoop;
use Mojo::File qw(tempfile);

get '/' => sub ($c) {
  my $input = tempfile->spurt($c->param('input'));
  Mojo::IOLoop->subprocess->run_p(sub {
    qx(myapp.pl -input=$input);
  })->then(sub (@results) {
    $c->render(text => join '', @results);
  })->catch(sub ($err) {
    $c->reply->exception($err);
  });
};

app->start;

[jhthorsen]

If you want the actual output, you can capture STDOUT using https://metacpan.org/pod/Mojo::IOLoop::ReadWriteFork

$fork->run_and_capture_p('myappl.pl', '-input=input.txt')->then(sub {
  my $asset = shift;
  $c->res->headers->content_type('text/plain');
  $c->reply->asset($asset);
});

However if the script runs for a long time and you want to guaranty that it completes you might want to look into https://docs.mojolicious.org/Minion instead.

[s1037989]

What are the differences between Subprocess and ReadWriteFork?

[jhthorsen]

Subprocess is for forking perl and run a callback in that fork (which could contain system()). The return value from the Subprocess sub, will be sent to the parent process.
ReadWriteFork is for running any program and piping STDIN/STDOUT/STDERR from and to that process. (ReadWriteFork can also run a callback, but it's all about I/O)