gistfile1.txt

#!/usr/bin/env perl

use strictures;
use PSGI::Syntax; #(signatures, etc. for example code)
use Future::AsyncAwait;
use Future;

### Basic ASGI App Implementation
async sub app($scope, $receive, $send) {
    if ($scope->{type} eq 'http') {
        # Start the HTTP response.
        await $send->({
            type    => "http.response.start",
            status  => 200,
            headers => [
                ["content-type", "text/plain"],
            ],
        });
        # Send the response body.
        await $send->({
            type => "http.response.body",
            body => "Hello, ASGI with middleware!",
        });
    }
}

### Logging Middleware Package

{
    package LoggingMiddleware;

    use strictures;
    use PSGI::Syntax; #(signatures, etc. for example code)
    use Future::AsyncAwait;
    use Future;

    # Constructor: wraps an ASGI app.
    sub new($class, $app) {
        return bless { app => $app }, $class;
    }

    # The middleware call method which logs before and after calling the app.
    async sub call($self, $scope, $receive, $send) {
        if ($scope->{type} eq 'http') {
            say "[Middleware] Request received: $scope->{path}";
        }
        # Call the next app (or middleware) in the stack.
        await $self->{app}->($scope, $receive, $send);
        if ($scope->{type} eq 'http') {
            say "[Middleware] Request processing completed.";
        }
    }
}

### Main Execution

# Wrap the basic app with logging middleware.
my $app_with_middleware = LoggingMiddleware->new(\&app);