Async Guzzle

blocking.php

<?php

require_once 'vendor/autoload.php';

function client()
{
    static $client;
    $client = $client ?? new GuzzleHttp\Client;
    return $client;
}

function makeRequest(int $delay)
{
    echo "Making request [delay = $delay]\n";

    client()->getAsync('https://mockbin.org/delay/' . $delay)
        ->then(function() use ($delay) {
            echo "Response received [delay = $delay]\n";
        })
        ->wait();
}

echo "Start\n";
$time = -time();

$delays = [5000, 2500, 1000, 500, 0];

foreach ($delays as $delay) {
    makeRequest($delay);
}

$time += time(); 

echo "Finished\n";
echo sprintf('Finished in %f seconds', $time);

concurrent.php

<?php

require_once 'vendor/autoload.php';

use GuzzleHttp\Promise\PromiseInterface;

function client()
{
    static $client;
    $client = $client ?? new GuzzleHttp\Client;
    return $client;
}

function makeRequest(int $delay): PromiseInterface
{
    echo "Making request [delay = $delay]\n";

    return client()->getAsync('https://mockbin.org/delay/' . $delay)
        ->then(function() use ($delay) {
            echo "Response received [delay = $delay]\n";
        });
}

echo "Start\n";
$time = -time(); 

$promises = [
    makeRequest(5000),
    makeRequest(2500),
    makeRequest(1000),
    makeRequest(500),
    makeRequest(0)
];

\GuzzleHttp\Promise\unwrap($promises);

$time += time(); 

echo "Finished\n";
echo sprintf('Finished in %f seconds', $time);

The above outputs:

>php blocking.php
Start
Making request [delay = 5000]
Response received [delay = 5000]
Making request [delay = 2500]
Response received [delay = 2500]
Making request [delay = 1000]
Response received [delay = 1000]
Making request [delay = 500]
Response received [delay = 500]
Making request [delay = 0]
Response received [delay = 0]
Finished
Finished in 9.000000 seconds

and

>php concurrent.php
Start
Making request [delay = 5000]
Making request [delay = 2500]
Making request [delay = 1000]
Making request [delay = 500]
Making request [delay = 0]
Response received [delay = 0]
Response received [delay = 500]
Response received [delay = 1000]
Response received [delay = 2500]
Response received [delay = 5000]
Finished
Finished in 6.000000 seconds