/**
* The Signature Base String is a consistent reproducible concatenation of the
* request elements into a single string. The string is used as an input in hashing or signing algorithms.
*
* The base string => $httpMethod&urlencode($url without query params)&urlencode(normalized_request_parameters)
* (Basically HTTP method(GET/POST etc), the URL(scheme://host/path, doesnt include the query string), and the norlalized request parameters
* each urlencoded and then concated with &.)
*/
private function getSignatureBaseString($httpMethod, $url, $oAuthOptions, &$debugInfo)
{
// Get the Query String parameters. Example if the request is http://photos.example.net/photos.aspx?file=vacation.jpg&size=original
// then get the query string and create an array from it in form of key value pairs
// $qsArray Key Value
// file vacation.jpg
// size original
$parts = parse_url($url);
$qs = $parts['query'];
parse_str($qs, $qsArray);
$signable_options = array_merge($oAuthOptions, $qsArray);
$signable_parameters = RequestSigner::getNormalizedRequestParameters($signable_options);
$normalized_url = Util::getNormalizedHttpUrl($url);
$debug = array();
$debug['HTTP Method'] = $httpMethod;
$debug['Normalized Url'] = $normalized_url;
$debug['Signable Parameters'] = $signable_parameters;
$debug['Query parameters'] = $qs;
$debugInfo['signature_base_string_parts'] = $debug;
$parts = array($httpMethod, $normalized_url, $signable_parameters);
// Url encode each of http method, Url(without query string), and the normalized parameters (oauth parameters, along with query string parameters)
$parts = Util::urlencode_rfc3986($parts);
// After url encoding, concatenate them with an &
return implode('&', $parts);
}
