| 1 | <?php |
| 2 | |
| 3 | class CRM_Utils_Http { |
| 4 | |
| 5 | /** |
| 6 | * Parse the expiration time from a series of HTTP headers. |
| 7 | * |
| 8 | * @param array $headers |
| 9 | * @return int|NULL |
| 10 | * Expiration tme as seconds since epoch, or NULL if not cacheable. |
| 11 | */ |
| 12 | public static function parseExpiration($headers) { |
| 13 | $headers = CRM_Utils_Array::rekey($headers, function ($k, $v) { |
| 14 | return strtolower($k); |
| 15 | }); |
| 16 | |
| 17 | if (!empty($headers['cache-control'])) { |
| 18 | $cc = self::parseCacheControl($headers['cache-control']); |
| 19 | if ($cc['max-age'] && is_numeric($cc['max-age'])) { |
| 20 | return CRM_Utils_Time::getTimeRaw() + $cc['max-age']; |
| 21 | } |
| 22 | } |
| 23 | |
| 24 | return NULL; |
| 25 | } |
| 26 | |
| 27 | /** |
| 28 | * @param string $value |
| 29 | * Ex: "max-age=86400, public". |
| 30 | * @return array |
| 31 | * Ex: Array("max-age"=>86400, "public"=>1). |
| 32 | */ |
| 33 | public static function parseCacheControl($value) { |
| 34 | $result = array(); |
| 35 | |
| 36 | $parts = preg_split('/, */', $value); |
| 37 | foreach ($parts as $part) { |
| 38 | if (strpos($part, '=') !== FALSE) { |
| 39 | list ($key, $value) = explode('=', $part, 2); |
| 40 | $result[$key] = $value; |
| 41 | } |
| 42 | else { |
| 43 | $result[$part] = TRUE; |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | return $result; |
| 48 | } |
| 49 | |
| 50 | } |