ToyCo are not happy...

Sophie cleared her throat, waited for Ernest, Santa's right-hand elf, to look up from his screen. "Boss. We have a problem."

"Oh?" He sighed. "What now?"

She gestured at the tablet she was holding. "You know that script we had that fetched new arrivals from their API? Well... it seems Santa wants those updates the instant they appear, so every department is running that script once a minute, and it's crippling ToyCo's servers." A pause. "Um, also we get duplicates because there are multiple copies of it running."

Ernest managed a slight frazzled grin. "You know how to fix that, at least."

She nodded. "Yes, but ToyCo also said they could push us a feed, if we set up a web server to accept it. How do we do that?"

Mojolicious::Lite

He chuckled for real this time. "Oh? that all? Easy. Watch and learn, young elf." With a few keystrokes, he opened an edit window on a new file called toyco_app.pl.

#!/usr/bin/env perl

use Mojolicious::Lite;

Sophie perked up. "What's that?"

"That? It's a very simple module that allows us to run up a web server. Here..."

post "/feeds/toyco" => sub {
    my $c = shift;
};

"It comes," he explained, "With a bunch of little helper subs that basically make up a tiny Domain Specific Language that will allow us to define stuff. So post says we want to accept a POST request at that URL, and then the $c argument contains the data we'll need to handle."

Sophie hmmed. "And we just tell them the URL? How...?"

He smirked. "I'll get to that. First up, let's parse the data. I'm assuming it's coming in the request body in the same JSON format as the last time?"

A nod. "Yes, but one item at a time, rather than a list."

Ok. That's easy. Back to our POST handler. $c->req is basically our incoming request, and Mojo has a really fast JSON parser built in that will give us the request body as a perl data structure...

post "/feeds/toyco" => sub {
    my $c = shift;
    my $item = $c->req->json;

    add_to_db(
        supplier => "ToyCo",
        SKU      => $item->{sku},
        name     => $item->{name},
        cost     => $item->{wholesale_price},
        RRP      => $item->{rrp},
    );
};

"Did they say if they expected any JSON back?"

Another glance at her tablet. "Just an optional message field with some arbitrary text."

Ernest hrmed. "Ok. Seems a bit pointless, but we could just do this before the end of the subroutine..."

$c->render( json => { message => "Accepted" }, status => 200 );

"...and there you go." He paused, laughed. "Whoops. Helps to start the app. So we stick this line at the end of the script proper..."

app->start;

Running and testing

Sophie hid a smile, then paused and worried at her bottom lip. "That's all very well, but how do we run it?"

Ernest gave her a pleased smile. "Thought you'd never ask. Ok. To test it, there's morbo, which is their development runner..."

morbo ./toyco_app.pl
Server available at http://*:3000

"There. That opens it by default listening on port 3000, so you can now test it by feeding it data via something like HTTPie."

Sophie's eyes widened. "What's that?"

He opened another terminal window. "It's a very handy script for making API requests - don't tell anyone, but it's written in Python. Google for it, and it's pretty easy to install - we have it on all our systems. So much easier than trying to remember all the incredibly cryptic flags for curl. And you can do this... You give it the body parameters as just key/value pairs in this case, and..."

http POST localhost:3000/feeds/toyco Content-Type:application/json \
    name="Santa Hat" rrp=36.50 wholesale_price=20.00 SKU=TC-03451
HTTP/1.1 200 OK
Content-Length: 38
Content-Type: application/json; charset=utf-8
Date: Tue, 02 Dec 2025 11:33:52 GMT
{
    "message": "Accepted"
}

"...and there you go..."

"But that's only development." Sophie frowned. "How do we get it up on production?"

"There's any number of ways. https://docs.mojolicious.org has pointers, but I guess what we'll do is ship it across to prod.northpole.net when it's good and tested..." He gave her a sly grin. "That's your job, by the way... and then'll we'll run it up using the prefork option under something like supervisor to restart it if it ever gets killed for some reason."

./toyco_app.pl prefork -l https://prod.northpole.net:10000

"And there we go." He sighed. "Right. Off you go and tidy that up and test it, and I'll get back to keeping Saint Nick out of Lima's restricted airspace."

"Still?" Sophie giggled.

"Still. Off with you, young elf."