private function prepareRequestHeader($uri, $http_method, $media_type, $metadata = null)
{
$headers = array();
// 1. Format date
$date = $this->getCurrentGMTTime();
$headers[Common::DATE] = $date;
// 2. Set content type
if ($media_type != NULL && !empty($media_type)) {
$headers[Common::CONTENT_TYPE] = $media_type;
}
if ($metadata != null) {
foreach ($metadata->getRawMetadata() as $key => $value) {
$headers[$key] = $value;
}
}
// 3. Set authorization information
$sign_uri = substr($uri, strpos($uri, "/", strpos($uri, ":") + 3));
$signature = Signer::signToBase64($http_method, $sign_uri, $headers, $this->credential->getGalaxyAccessSecret(), self::SIGN_ALGORITHM);
$auth_string = "Galaxy-V2 " . $this->credential->getGalaxyAccessId() . ":" . $signature;
$headers[Common::AUTHORIZATION] = $auth_string;
return $headers;
}
