Dealing with spatie asynchronous error handling - php

Question

I'm working on an asynchronous process on a PHP project. I'm using a library named spatie/async. The code snippet is like below :
foreach (range(1, 2) as $i) {
$pool->add(function () use ($i) {
// Do a thing
try {
$result = $i / 0; // This will cause an error
return "Works";
} catch (\Exception $e) {
return -1;
}
})->then(function ($output) {
// Handle success
echo (output . "\n");
})->catch(function ($exception) {
// When an exception is thrown, it's caught and passed here.
echo "Sounds good, but don't work\n";
})
}
$pool->wait();
All I want is when the $result got an error, it will go into the inner catch, but instead, it goes down to the bottom catch which causing a different result from what I want.
The result that I want is :
-1
-1
But instead, the result is :
Sounds good, but don't work
Sounds good, but don't work
Can anyone help me to achieve the result as I want?

Answer 1

The problem of your code is, that it does not throw an Exception in the add method call. A division by 0 is just causing an error, but not ein exception. Instead of changing the whole php error handler, I 'd suggest to extend your logic a little bit in your add method call.
$divisor = 0;
$pool->add(function() use ($i, $divisor) {
try {
if ($divisor === 0) {
throw new \LogicException('Division by zero!');
}
return $i / $divisor;
} catch (\LogicException $e) {
return -1;
}
});
Another solution could be changing the error handling for the pool method call.
set_error_handler(function () {
throw new \LogicException('Ouch!');
});
$pool->add(function() use ($i) {
try {
$result = $i / 0;
} catch (\LogicException $e) {
return -1;
}
});
restore_error_handler();
Caution! Changing the error handler affects all upcoming errors. Even the errors thrown in your used library. Keep in mind, that these are code snippets. This is not tested or thougt to be used in production. Hope that helps out a little bit.