Test performance of three determine content type methods

test_performance_determine_content_type.php

<?php

class A
{
    protected $knownTypes = [
        'application/json' => true,
        'application/xml'  => true,
        'text/xml'         => true,
        'text/html'        => true,
    ];
    protected $keys;
    protected $accept;

    public function __construct($acceptHeader = '')
    {
        $this->accept = $acceptHeader;
        $this->keys   = array_keys($this->knownTypes);
    }

    public function methodOne()
    {
        $selectedContentTypes = array_intersect(explode(',', $this->accept), $this->keys);

        if (count($selectedContentTypes)) {
            return $selectedContentTypes[0];
        }

        return 'text/html';
    }

    public function methodTwo()
    {
        foreach (explode(',', $this->accept) as $accept) {
            if (in_array($accept, $this->keys)) {
                return $accept;
            }
        }

        return 'text/html';
    }

    public function methodThree()
    {
        foreach (explode(',', $this->accept) as $accept) {
            if (isset($this->knownTypes[$accept])) {
                return $accept;
            }
        }

        return 'text/html';
    }
}

$a = new A('text/json,text/html,*/*');

$start = microtime(true);
echo $a->methodOne() . PHP_EOL;
$one = microtime(true);
echo $a->methodTwo() . PHP_EOL;
$two = microtime(true);
echo $a->methodThree() . PHP_EOL;
$three = microtime(true);

printf("one: %f\ntwo: %f\nthree: %f", $one - $start, $two - $one, $three - $two);