Step 1 - Get a request token

<?php
define
('OAUTH_CONSUMER_KEY','f670ca415f673fb613cfcf6bc0bc20');
define('OAUTH_CONSUMER_SECRET','09f28ded59');
$req_url 'http://sandbox.wepayapi.com/v1/oauth/request_token';
try {
  
$o = new OAuth(OAUTH_CONSUMER_KEY,OAUTH_CONSUMER_SECRET,
                 
OAUTH_SIG_METHOD_HMACSHA1,OAUTH_AUTH_TYPE_FORM);
  
$o->enableDebug();
  
$resp $o->getRequestToken($req_url);
} catch(
OAuthException $E) {
  echo 
"Response: "$E->lastResponse "\n";
}
file_put_contents("/tmp/last_request",$resp['oauth_token']."\n".
                  
$resp['oauth_token_secret']."\n");
echo 
'<a target="_blank" href="'.$resp['login_url'].'">'.
     
$resp['login_url'].'</a>';
?>
Output