Facebook - when does the SDK refresh the auth token?

Question

According to the Facebook docs, mobile SDKs generate long lived tokens which are refreshed once per day when the person using your app makes a request to the Facebook servers. For the javascript SDK, short-lived tokens are generated and are refreshed periodically.

I'm curious as to what is meant by "the person using your app makes a request to the Facebook servers". Which calls specifically will cause the token to be refreshed? Or more importantly, which calls won't? Is it enough to check the login status or is something more active required? What I'm really interested in is keeping the token alive (or getting a new one) without sending the user back through the login flow, or doing anything that's particularly active with Facebooks APIs.

Thanks!

Answer 1

According to Facebook SDK Docu

Once a token expires ("auto" extend of Facebook SDK Token)

At any point, you can generate a new long-lived token by sending the person back to the login flow used by your web app - note that the person will not actually need to login again, they have already authorized your app, so they will immediately redirect back to your app from the login flow with a refreshed token

THERE IS no keep alive functionality in Facebook SDK.

User access tokens come in two forms: short-lived tokens and long-lived tokens. Short-lived tokens usually have a lifetime of about an hour or two, while long-lived tokens usually have a lifetime of about 60 days. You should not depend on these lifetimes remaining the same - the lifetime may change without warning or expire early. See more under handling errors.

long-lived = 60 days

Short-lived = 2 hour

Also according to Facebook SDK Docu

Mobile apps that use Facebook's mobile SDKs get long-lived tokens.

Once you force a user for a new oAuth/login, he will receive a new token. The old one will not expire. You are able to check the loginStatusby FB.getLoginStatus. No need for a keep alive.