FIWARE-Lab KeyRock Access Token Request error - fiware

Question

I'm testing the Authorization Code Grant protocol on the instance of KeyRock GE at FIWARE-Lab using DHC web client.
So far I have succeeded on implementing the Authorization Request, and I obtain the code to be used on the Access Token Request. The URL for the Authorization Request is the following (although not executed on DHC, but on a regular browser so I can introduce my user and password):
https://account.lab.fiware.org/oauth2/authorize/?response_type=code&client_id=2122&redirect_uri=http%3A%2F%2Flocalhost%2FCallback
I have checked that the client_id and the redirect_uri are both correct against the values related with my application at my account at FIWARE-Lab.
Executing the following request (can't post images, so I'll describe)
POST
https:// account.lab.fiware.org/oauth2/token?grant_type=authorization_code&code=<code>&redirect_uri=http%3A%2F%2Flocalhost%2FCallback -- <code> is the code obtained on the Auth. Request
Authorization: Basic <XXXX> --- <XXXX> is the result of base64(client_id+":"+client_secret)
Content-Type: application/x-www-form-urlencoded
...I get the following error message:
{
"error":{
"message": "create_access_token() takes exactly 3 arguments (2 given)",
"code": 400,
"title": "Bad Request"
}
}
I've checked the authorization is correct (Basic using the OAuth credentials from my application), and I'm using the same redirect_uri used at the previous Authorization Request, and the code obtained from it.
¿What is wrong?
P.S.: If I remove any or all of the query parameters, I still get the same error

Answer 1

Don't pass the parameters in the url. Instead, add them to request's body as query string:
POST /oauth2/token HTTP/1.1
Host: account.lab.fiware.org
Content-Type: application/x-www-form-urlencoded
Authorization: Basic <XXXX> --- <XXXX>
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded
grant_type=authorization_code&code=1234&redirect_uri=http%3A%2F%2Flocalhost%3A9000%2Fcodecallback.html

Answer 2

I suggest to follow the steps in the presentation:
Adding Identity Management and Access Control to your Application
It gives you details about what are the different requests that you have to follow and also what are the expected response of them.