WordPress "Expect" header fix

expect-header-fix.php

<?php

/**
 * By default, cURL sends the "Expect" header all the time which severely impacts
 * performance. Instead, we'll send it if the body is larger than 1 mb like
 * Guzzle does.
 */
function add_expect_header(array $arguments)
{
    $arguments['headers']['expect'] = '';
    
    if (is_array($arguments['body'])) {
        $bytesize = 0;
        $iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($arguments['body']));

        foreach ($iterator as $datum) {
            $bytesize += strlen((string) $datum);

            if ($bytesize >= 1048576) {
                $arguments['headers']['expect'] = '100-Continue';
                break;
            }
        }
    } elseif (!empty($arguments['body']) && strlen((string) $arguments['body']) > 1048576) {
        $arguments['headers']['expect'] = '100-Continue';
    }

    return $arguments;
}
add_filter('http_request_args', 'add_expect_header');

It works great, but i still get "Array to string conversion", on this line:

$body = $arguments['body'];

    if ( is_array( $body ) )
	{
        $body = implode('', $body);  // not always, but sometimes i get "Array to string conversion" notice
    }

I'm not yet ready for WP 5.8, since big changes in widgets and my woocommerce plugins, etc

@Lolosan do you still get it with the updated code?

@Lolosan do you still get it with the updated code?

Thank you for the updated code, I'm testing in a woocommerce site with heavy use of APIs and everything seems great

This fix already comes with WP5.8, right? No need to use it after?

@Lolosan That's correct 😄