/**
* Decode an HTTP Response.
* @static
* @throws apiServiceException
* @param apiHttpRequest $response The http response to be decoded.
* @return mixed|null
*/
static function decodeHttpResponse($response)
{
$code = $response->getResponseHttpCode();
$body = $response->getResponseBody();
$decoded = null;
if ($code != '200' && $code != '201' && $code != '204') {
$decoded = json_decode($body, true);
$err = 'Error calling ' . $response->getMethod() . ' ' . $response->getUrl();
if ($decoded != null && isset($decoded['error']['message']) && isset($decoded['error']['code'])) {
// if we're getting a json encoded error definition, use that instead of the raw response
// body for improved readability
$err .= ": ({$decoded['error']['code']}) " . $decoded['error']['message'];
} else {
$err .= ": ({$code}) {$body}";
}
throw new apiServiceException($err);
}
// Only attempt to decode the response, if the response code wasn't (204) 'no content'
if ($code != '204') {
$decoded = json_decode($body, true);
if ($decoded == null) {
throw new apiServiceException("Invalid json in service response: {$body}");
}
}
return $decoded;
}
/**
* Check if an HTTP response can be cached by a private local cache.
*
* @static
* @param apiHttpRequest $resp
* @return bool True if the response is cacheable.
* False if the response is un-cacheable.
*/
public static function isResponseCacheable(apiHttpRequest $resp)
{
$method = $resp->getRequestMethod();
if (!in_array($method, self::$CACHEABLE_HTTP_METHODS)) {
return false;
}
$code = $resp->getResponseHttpCode();
if (!in_array($code, self::$CACHEABLE_STATUS_CODES)) {
return false;
}
// The resource is uncacheable if the resource is already expired and
// the resource doesn't have an ETag for revalidation.
$etag = $resp->getResponseHeader("etag");
if (self::isExpired($resp) && $etag == false) {
return false;
}
// [rfc2616-14.9.2] If [no-store is] sent in a response, a cache MUST NOT
// store any part of either this response or the request that elicited it.
$cacheControl = $resp->getParsedCacheControl();
if (in_array('no-store', $cacheControl)) {
return false;
}
// Pragma: no-cache is an http request directive, but is occasionally
// used as a response header incorrectly.
$pragma = $resp->getResponseHeader('pragma');
if ($pragma == 'no-cache' || strpos($pragma, 'no-cache') !== false) {
return false;
}
// [rfc2616-14.44] Vary: * is extremely difficult to cache. "It implies that
// a cache cannot determine from the request headers of a subsequent request
// whether this response is the appropriate representation."
// Given this, we deem responses with the Vary header as uncacheable.
$vary = $resp->getResponseHeader('vary');
if ($vary) {
return false;
}
return true;
}
