Context in Perl

Here’s the translation of the Go code to Perl, with explanations in Markdown format suitable for Hugo:

In this example, we’ll look at setting up a simple HTTP server in Perl. HTTP servers are useful for demonstrating the usage of signal handling for controlling cancellation. While Perl doesn’t have a direct equivalent to Go’s context.Context, we can achieve similar functionality using signal handling.

#!/usr/bin/env perl

use strict;
use warnings;
use HTTP::Server::Simple::CGI;
use Time::HiRes qw(sleep);
use POSIX qw(:signal_h);

my $server = MyWebServer->new(8090);
$server->run();

{
    package MyWebServer;
    use base qw(HTTP::Server::Simple::CGI);

    sub handle_request {
        my ($self, $cgi) = @_;

        print "HTTP/1.0 200 OK\r\n";
        print $cgi->header('text/plain');

        print "server: hello handler started\n";

        # Set up signal handling
        my $keep_going = 1;
        local $SIG{INT} = sub { $keep_going = 0 };

        # Simulate some work
        for (1..10) {
            last unless $keep_going;
            sleep(1);
        }

        if ($keep_going) {
            print "hello\n";
        } else {
            print "server: request canceled\n";
        }

        print "server: hello handler ended\n";
    }
}

In this Perl version:

1. We use the HTTP::Server::Simple::CGI module to create a simple HTTP server.

2. The handle_request method is equivalent to the hello function in the Go example. It handles incoming requests.

3. We use $SIG{INT} to set up a signal handler for the interrupt signal (Ctrl+C). This is similar to how the Go version uses ctx.Done() to detect cancellation.

4. The sleep loop simulates work being done, checking the $keep_going flag on each iteration. This is analogous to the select statement in the Go version.

5. If the work completes without interruption, we print “hello”. If interrupted, we print a cancellation message.

To run the server:

$ perl server.pl &

To simulate a client request and cancellation:

$ curl localhost:8090/hello
server: hello handler started
^C
server: request canceled
server: hello handler ended

This Perl version demonstrates how to handle cancellation in a long-running HTTP request handler, similar to the Go example but using Perl-specific constructs and idioms.