问如何在PHP中选择HTTP Accept头中的内容类型

EN

function getBestSupportedMimeType($mimeTypes = null) {
    // Values will be stored in this array
    $AcceptTypes = Array ();

    // Accept header is case insensitive, and whitespace isn’t important
    $accept = strtolower(str_replace(' ', '', $_SERVER['HTTP_ACCEPT']));
    // divide it into parts in the place of a ","
    $accept = explode(',', $accept);
    foreach ($accept as $a) {
        // the default quality is 1.
        $q = 1;
        // check if there is a different quality
        if (strpos($a, ';q=')) {
            // divide "mime/type;q=X" into two parts: "mime/type" i "X"
            list($a, $q) = explode(';q=', $a);
        }
        // mime-type $a is accepted with the quality $q
        // WARNING: $q == 0 means, that mime-type isn’t supported!
        $AcceptTypes[$a] = $q;
    }
    arsort($AcceptTypes);

    // if no parameter was passed, just return parsed data
    if (!$mimeTypes) return $AcceptTypes;

    $mimeTypes = array_map('strtolower', (array)$mimeTypes);

    // let’s check our supported types:
    foreach ($AcceptTypes as $mime => $q) {
       if ($q && in_array($mime, $mimeTypes)) return $mime;
    }
    // no mime-type found
    return null;
}

$mime = getBestSupportedMimeType(Array ('application/xhtml+xml', 'text/html'));

/**
 * Parse, sort and select best Content-type, supported by a user browser.
 *
 * @param string|string[] $desiredTypes The filter of desired types. If &null then the all supported types will returned.
 * @param string $acceptRules Supported types in the HTTP Accept header format. $_SERVER['HTTP_ACCEPT'] by default.
 * @return string|string[]|null Matched by $desiredTypes type or all accepted types.
 * @link Inspired by http://stackoverflow.com/a/1087498/3155344
 */
function resolveContentNegotiation($desiredTypes = null, $acceptRules = null)
{
    if (!$acceptRules) {
        $acceptRules = @$_SERVER['HTTP_ACCEPT'];
    }
    // Accept header is case insensitive, and whitespace isn't important.
    $acceptRules = strtolower(str_replace(' ', '', $acceptRules));

    $sortedAcceptTypes = array();
    foreach (explode(',', $acceptRules) as $acceptRule) {
        $q = 1; // the default accept quality (rating).
        // Check if there is a different quality.
        if (strpos($acceptRule, ';q=') !== false) {
            // Divide "type;q=X" into two parts: "type" and "X"
            list($acceptRule, $q) = explode(';q=', $acceptRule, 2);
        }
        $sortedAcceptTypes[$acceptRule] = $q;
    }
    // WARNING: zero quality is means, that type isn't supported! Thus remove them.
    $sortedAcceptTypes = array_filter($sortedAcceptTypes);
    arsort($sortedAcceptTypes, SORT_NUMERIC);

    // If no parameter was passed, just return parsed data.
    if (!$desiredTypes) {
        return $sortedAcceptTypes;
    }

    $desiredTypes = array_map('strtolower', (array) $desiredTypes);

    // Let's check our supported types.
    foreach (array_keys($sortedAcceptTypes) as $type) {
        foreach ($desiredTypes as $desired) {
            if (fnmatch($desired, $type)) {
                return $type;
            }
        }
    }

    // No matched type.
    return null;
}