TaskSet::getIterator

(PHP 8.6+, True Async 1.0)

public TaskSet::getIterator(): Iterator

Returns an iterator that yields results as tasks complete. TaskSet implements IteratorAggregate, so you can use foreach directly.

Each processed entry is automatically removed from the set, freeing memory and decreasing count().

Iterator Behavior

foreach suspends the current coroutine until the next result is available
The key is the same one assigned during spawn() or spawnWithKey()
The value is an array [mixed $result, ?Throwable $error]:
- Success: [$result, null]
- Error: [null, $error]
Iteration ends when the set is sealed and all tasks have been processed
If the set is not sealed, foreach suspends waiting for new tasks

Important: Without calling seal(), iteration will wait indefinitely.

Examples

Example #1 Streaming processing

<?php

use Async\TaskSet;

spawn(function() {
    $set = new TaskSet(concurrency: 5);

    for ($i = 0; $i < 100; $i++) {
        $set->spawn(fn() => processItem($items[$i]));
    }
    $set->seal();

    foreach ($set as $key => [$result, $error]) {
        if ($error !== null) {
            echo "Task $key: error — {$error->getMessage()}\n";
            continue;
        }
        echo "Task $key: done\n";
        // Entry removed, memory freed
    }

    echo $set->count() . "\n"; // 0
});

Example #2 Named keys

<?php

use Async\TaskSet;

spawn(function() {
    $set = new TaskSet();

    $set->spawnWithKey('users', fn() => fetchUsers());
    $set->spawnWithKey('orders', fn() => fetchOrders());
    $set->seal();

    foreach ($set as $key => [$result, $error]) {
        if ($error === null) {
            echo "$key: received " . count($result) . " records\n";
        }
    }
});

Documentation

TaskSet::getIterator

Iterator Behavior

Examples

Example #1 Streaming processing

Example #2 Named keys

See Also