Symfony HttpClient Async example

symfony-http-client-async-example.php

<?php

$client = \Symfony\Component\HttpClient\HttpClient::create();

// Create a few requests: this is entierely async, requests are launched in the background
$request1 = $client->request('GET', 'http://releases.ubuntu.com/18.04.2/ubuntu-18.04.2-desktop-amd64.iso?request=a');
$request2 = $client->request('GET', 'http://releases.ubuntu.com/18.04.2/ubuntu-18.04.2-desktop-amd64.iso?request=b');
$request3 = $client->request('GET', 'http://releases.ubuntu.com/18.04.2/ubuntu-18.04.2-desktop-amd64.iso?request=c');

// The code continues execution immediatly, you can do whathever you want here ...

// Now if you call getContent or getStatusCode on one of the requests, you will get a blocking wait
// for this specific request: $request1->getContent(); would only wait for request 1, if request 2 & 3
// take mucher longer we wouldn't wait for them now.

// But to achieve real async, you can go even further and use stream():

// Infinite loop, for instance an event-loop
while (true) {
    // Create an iterable stream for all the requests
    // A timeout of 0 means don't wait any requests and give me only the responses chunks which are ready right now
    $stream = $client->stream([$request1, $request2, $request3], 0);

    foreach ($stream as $response => $chunk) {
        if ($chunk->isTimeout()) {
            echo 'Chunk received from response '.$response->getInfo('url')."\n";
        }
    }

    // Chunking with stream() also means support for HTTP2 push out of the box

    // Code here will be executed regularly, between the chunks arriving in the background ...
}