(PECL OAuth >=0.99.7)
oauth_get_sbs — Generate a Signature Base String
$http_method
   , string $uri
   [, array $request_parameters
  ] )Generates a Signature Base String according to pecl/oauth.
http_method
     The HTTP method.
uri
     URI to encode.
request_parameters
     Array of request parameters.
Returns a Signature Base String.