Documentation

Learn how to use TrueAsync for building concurrent PHP applications.

Channel::getIterator

(PHP 8.6+, True Async 1.0)

public Channel::getIterator(): \Iterator

Returns an iterator for traversing channel values. Channel implements the IteratorAggregate interface, so you can use foreach directly.

The iterator suspends the current coroutine while waiting for the next value. Iteration terminates when the channel is closed and the buffer is empty.

Important: If the channel is never closed, foreach will wait for new values indefinitely.

Return values

An \Iterator object for traversing channel values.

Examples

Example #1 Reading a channel with foreach

<?php

use Async\Channel;

$channel = new Channel(10);

spawn(function() use ($channel) {
    $channel->send('one');
    $channel->send('two');
    $channel->send('three');
    $channel->close(); // without this, foreach will never terminate
});

spawn(function() use ($channel) {
    foreach ($channel as $value) {
        echo "Received: $value\n";
    }
    echo "All values processed\n";
});

Example #2 Producer-consumer pattern

<?php

use Async\Channel;

$jobs = new Channel(20);

// Producer
spawn(function() use ($jobs) {
    $urls = ['https://example.com/1', 'https://example.com/2', 'https://example.com/3'];

    foreach ($urls as $url) {
        $jobs->send($url);
    }
    $jobs->close();
});

// Consumer
spawn(function() use ($jobs) {
    foreach ($jobs as $url) {
        $response = httpGet($url);
        echo "Downloaded: $url ({$response->status})\n";
    }
});

See also