Facebook authentication for both mobile & web app in Cakephp -

can me overcome hurdle..

my situation:

i have webapp (facebook app) in cakephp, b accessed after facebook authentication(its working cool).

& have mobile app & work on restapi, want same above webapp code served restapi.

now i'm able authentication mobile app facebook, need authenticate webapp server rest api(unless cannot use code inside app)..

requirement:

i have access_token & user_id me sent facebook mobile after successful login, & how can authenticate web app these two..??

can & me comeout..!!?

if want access facebook data inside cakephp have send access_token & user_id cakephp. should narrow down problem specific error or method fails, here it's not clear problem lies.