How to can I write php asynchroneous functions using reactphp

Question

I thought I can do more at same time so I started with reactphp. The code runs so fine, but I wanted to be sure that the code was indeed asynchroneous I tried the code below which gave me no confidence, it echoed the strings 'in natural order' like "one two three four..." but I was looking for output like "one four three two..." just as it happens in javascript.

function callDone(){
    $g = 'abcdefghuytegbnwsgwseeveddvvdvdcvdvbshasfcfddbbcdgcdvoiuyyttreewwaazxcvbnjjjhgfffhhhabcdefghuytegbnwsgwseeveddvvdvdcvdvbshasfcfddbbcdgcdvoiuyyttreewwaazxcvbnjjjhgfffhhh';
    $r = str_split($g);
    for($i=0;$i<count($r);$i++){
        $g .= $r[$i];
    }
    return 1;
}
$promise = new React\Promise\Promise(function($resolve){
    echo microtime(true). "<br>start<br>";
    $resolve(callDone());
}
$promise->then(function($v){
    echo 'one<br>';
});
$promise->then(function($v){
    echo 'two<br>';
});
$promise->then(function($v){
    echo 'three<br>';
});
$promise->then(function($v){
    echo 'four<br>';
});
$promise->then(function($v){
    echo 'five<br>';
});

this will print "one two three four five" But I needed something out of order like: "one three two..." to confirm this is really asynchroneous. Any help thanks in advance.

PHP will always go line by line and wait for the previous one to finish before continuing. I don't quite understand, what you planing to achieve :/ — Peon, Oct 30 '18 at 07:45
You could try and add `sleep(1);` to one function and see if the other items finish before it. — Nigel Ren, Oct 30 '18 at 07:54
the concept of reactphp proclaims asynchroneous code excecution but their examples seem to cover only non-blocking I/O operations event loops... — smacaz, Oct 30 '18 at 08:14
To get async result of sync code you should split the process to at least 2 queues — Alex Slipknot, Oct 30 '18 at 08:42

score 1 · Accepted Answer · answered Oct 30 '18 at 08:42

The problem with the your example is the expectation that these calls should be some kind randomized. The asynchronous aspect of ReactPHP comes mostly from the event-loop which must be non-blocking(as you mentioned in one of the comments below). Not using the event-loop means you are using the standard call stack of PHP.

If you want to see an "more asynchronous" approach you could modify your code a bit.

$loop = \React\EventLoop\Factory::create();

function callDone(){
    $g = 'abcdefghuytegbnwsgwseeveddvvdvdcvdvbshasfcfddbbcdgcdvoiuyyttreewwaazxcvbnjjjhgfffhhhabcdefghuytegbnwsgwseeveddvvdvdcvdvbshasfcfddbbcdgcdvoiuyyttreewwaazxcvbnjjjhgfffhhh';
    $r = str_split($g);
    for($i=0;$i<count($r);$i++){
        $g .= $r[$i];
    }
    return 1;
}
$promise = new React\Promise\Promise(function($resolve){
    echo microtime(true). "<br>start<br>";
    $resolve(callDone());
});

$promise->then(function($v) use ($loop) {
    $loop->addPeriodicTimer(0.1, function () {
        echo 'one<br>';
    });
});

$promise->then(function($v) use ($loop) {
    $loop->addPeriodicTimer(0.2, function () {
        echo 'two<br>';
    });
});
$promise->then(function($v){
    echo 'three<br>';
});
$promise->then(function($v){
    echo 'four<br>';
});
$promise->then(function($v){
    echo 'five<br>';
});

$loop->run();

We added the event-loop to your code to start a more asynchronous approach. This will add an asynchronous time to your example which will echo "one" every 0.1 seconds and "two" every 0.2 seconds. As you may see these two timers won't block each other because the event-loop handles these timers. I hope this helps!

How to can I write php asynchroneous functions using reactphp

1 Answers1