const express = require('express');
const app = express();
const { Cluster } = require('../dist');

(async () => {
    const cluster = await Cluster.launch({
        concurrency: Cluster.CONCURRENCY_CONTEXT,
        maxConcurrency: 2,
    });
    await cluster.task(async ({ page, data: url }) => {
        // make a screenshot
        await page.goto('http://' + url);
        const screen = await page.screenshot();
        return screen;
    });

    // setup server
    app.get('/', async function (req, res) {
        if (!req.query.url) {
            return res.end('Please specify url like this: ?url=example.com');
        }
        try {
            const screen = await cluster.execute(req.query.url);

            // respond with image
            res.writeHead(200, {
                'Content-Type': 'image/jpg',
                'Content-Length': screen.length
            });
            res.end(screen);
        } catch (err) {
            // catch error
            res.end('Error: ' + err.message);
        }
    });

    app.listen(3000, function () {
        console.log('Screenshot server listening on port 3000.');
    });
})();