search.js

addEventListener("fetch", event => {
    event.respondWith(handler(event.request));
});

const query = `
  repo = from(bucket:"mirrorz")
    |> range(start: -10m)
    |> filter(fn: (r) => r._measurement == "repo" and r.name == "reponame")
    |> map(fn: (r) => ({_value:r._value,mirror:r.mirror,_time:r._time,path:r.url}))
    |> tail(n:1)

  site = from(bucket:"mirrorz")
    |> range(start: -10m)
    |> filter(fn: (r) => r._measurement == "site")
    |> map(fn: (r) => ({mirror:r.mirror,url:r.url}))
    |> tail(n:1)

  join(tables: {repo: repo, site: site}, on: ["mirror"])
    |> map(fn: (r) => ({_value:r._value,mirror:r.mirror,url:r.url+r.path,_time:r._time}))
`

function is_debug(request) {
    const params = {};
    const req_url = new URL(request.url);
    const queryString = req_url.search.slice(1).split('&');
    queryString.forEach(item => {
        const kv = item.split('=')
        if (kv[0]) {
            if (kv[0] in params) {
                params[kv[0]].push(kv[1] || true)
            } else {
                params[kv[0]] = [kv[1] || true]
            }
        }
    });
    return ('debug' in params);
}

function mirrors(csv) {
    const urls = [];

    for (const line of csv.split('\r\n')) {
        const arr = line.split(',')
        if (arr.length < 7)
            continue
        if (arr[1] !== "_result")
            continue
        try {
            urls.push(arr[6])
        } catch (e) {}
    }
    return urls;
}

async function fetch_timeout(url) {
    let fetchPromise = fetch(url, {method: 'HEAD'})
    let timeoutPromise = new Promise(resolve => setTimeout(resolve, 10*1000))
    let response = await Promise.race([fetchPromise, timeoutPromise])
    return response ? response.status.toString() : "Timeout"
}

async function handler(request) {
    try {
        let pathname = (new URL(request.url)).pathname;
        let pathname_arr = pathname.split('/');
        
        // Redirect to homepage
        if (pathname_arr[1].length === 0)
            return Response.redirect('https://mirrorz.org/about', 302);

        // Query influxdb 2.x
        response = await fetch(INFLUX_URL, {
            headers: {
                'Authorization': INFLUX_TOKEN,
                'Content-Type': 'application/vnd.flux',
            },
            method: "POST",
            body: query.replace('reponame', pathname_arr[1]),
        });

        const csv = await response.text();
        if (is_debug(request)) 
            return new Response(csv);

        const urls = mirrors(csv);

        if (urls.length === 0)
            return new Response(`Not Found`, {status: 404});
        
        const p = [], f = [];

        for (const url of urls) {
            // Append the remaining path
            let remain_path = pathname.substr(1+pathname_arr[1].length);
            // Dark magic for some sites treating '/archlinux' as file, not directory
            if (remain_path.length === 0 && !pathname.endsWith('/'))
                remain_path = '/'
            const full_url = url + remain_path;
            f.push(full_url)
            p.push(fetch_timeout(full_url));
        }

        const statuses = await Promise.all(p)

        let page = ""

        for (const i in urls)
            page += statuses[i] + " " + f[i] + "\n"

        return new Response(page);

    } catch (err) {
        return new Response(`${err}`, { status: 500 })
    }
}