index.ts

import { Request,  Response, Fastly } from "@fastly/as-compute";

const HTTPBIN_BACKEND = "httpbin";

function badRequest(): Response {
    return new Response(String.UTF8.encode("Bad request"), {
        status: 400
    });
}

function uuidHandler(req: Request): Response {
    let parts = req.url().split("/");
    if (parts.length != 5) {
        return badRequest();
    }

    let i = parts[4];
    let limit = I32.parseInt(i);
    if(isNaN(limit)) {
        return badRequest();
    }

    let pool = new Fastly.FetchPool();

    let headers = req.headers();
    headers.set("Host", "httpbin.org");

    let cacheOverride = new Fastly.CacheOverride();
    cacheOverride.setTTL(0);

    for(let i = 0; i < limit; i++) {
        let r = new  Request("https://httpbin.org/uuid", {
            method: "GET",
            headers: headers,
            body: null
        });
        pool.push(Fastly.fetch(r, {
            backend: HTTPBIN_BACKEND,
            cacheOverride,
        }));
    }

    let json = pool.all().reduce((json, r, i, arr) => {
        json += r.response.text();
        if(i != arr.length-1) json += ",";
        return json;
    }, "[") + "]";

    json = json.replaceAll(" ", "");
    json = json.replaceAll("\n", "");

    return new Response(String.UTF8.encode(json), { status: 200 });
}

function main(req: Request): Response {
    let method = req.method();
    let urlParts = req.url().split("//").pop().split("/");
    let host = urlParts.shift();
    let path = "/" + urlParts.join("/");

    if (method == "GET" && path.startsWith("/uuid")) {
        return  uuidHandler(req);
    }

    return new Response(String.UTF8.encode("The page you requested could not be found"), {
        status: 200,
    });
}

let req = Fastly.getClientRequest();
let resp = main(req);