I'm trying to use LTI to integrate an LMS (Canvas) with my 3rd party learning tool. As part of the process, I'm taking the Request variables as sent to me by Canvas:
Array ( [oauth_consumer_key] => key
[oauth_nonce] => s78gkWprnVJ6qp2UaCaEZ39WoYm91yOztiCBRhDx7s
[oauth_signature] => l82UMpiOt62vTd7Eu4GzyVVxYk0=
[oauth_signature_method] => HMAC-SHA1
[oauth_timestamp] => 1367072335 [oauth_version] => 1.0 )
and sending them via a header to my "request_token.php" script (taken from google's oAuth code). The result is Invalid signature. I've tested the code locally, however, and it seems to work fine when not pulling the info from my LMS. I've var_dumped the OAuthRequest object as a further indication that it looks like the OAuthRequest is in fact using the correct variables.
OAuthRequest Object
( [parameters:protected] =>
Array ( [oauth_consumer_key] => key
[oauth_nonce] => s78gkWprnVJ6qp2UaCaEZ39WoYm91yOztiCBRhDx7s
[oauth_signature] => l82UMpiOt62vTd7Eu4GzyVVxYk0=
[oauth_signature_method] => HMAC-SHA1
[oauth_timestamp] => 1367072335 [oauth_version] => 1.0 )
[http_method:protected] => GET
[http_url:protected] => http://www.itsmorethanatextbook.com:80/oauth/example/request_token.php?oauth_consumer_key=key&oauth_nonce=s78gkWprnVJ6qp2UaCaEZ39WoYm91yOztiCBRhDx7s&oauth_signature=l82UMpiOt62vTd7Eu4GzyVVxYk0=&oauth_signature_method=HMAC-SHA1&oauth_timestamp=1367072335&oauth_version=1.0
[base_string] => GET&http%3A%2F%2Fwww.itsmorethanatextbook.com%2Foauth%2Fexample%2Frequest_token.php&oauth_consumer_key%3Dkey%26oauth_nonce%3Ds78gkWprnVJ6qp2UaCaEZ39WoYm91yOztiCBRhDx7s%26oauth_signature_method%3DHMAC-SHA1%26oauth_timestamp%3D1367072335%26oauth_version%3D1.0 )
Might there be some additional step that one needs to take with the LTI variables to make it work? (I tried encoding them but to no avail)