Programming Working Journal

Facebook (2h)

Here is the exact page for the log in system.
https://developers.facebook.com/docs/reference/javascript/FB.login/

and this
https://developers.facebook.com/docs/reference/api/permissions/


And then, spend more time on the Java SDK
https://developers.facebook.com/docs/reference/javascript/


Get stuck here:
What is A_CODE_GENERATED_BY_SERVER ?

https://developers.facebook.com/docs/authentication/#authenticating-users-in-a-web-application

f the user presses Allow, your app is authorized. The OAuth Dialog will redirect (via HTTP 302) the user's browser to the URL you passed in the redirect_uri parameter with an authorization code:

http://YOUR_URL?code=A_CODE_GENERATED_BY_SERVER

With this code in hand, you can proceed to the next step, app authentication, to gain the access token you need to make API calls.

In order to authenticate your app, you must pass the authorization code and your app secret to the Graph API token endpoint - along with the exact same redirect_uri used above - athttps://graph.facebook.com/oauth/access_token. The app secret is available from the Developer App and should not be shared with anyone or embedded in any code that you will distribute (you should use the client-side flow for these scenarios).

https://graph.facebook.com/oauth/access_token?
     client_id=YOUR_APP_ID&redirect_uri=YOUR_URL&
     client_secret=YOUR_APP_SECRET&code=THE_CODE_FROM_ABOVE

If your app is successfully authenticated and the authorization code from the user is valid, the authorization server will return the access token:

In addition to the access token (the access_token parameter), the response contains the number of seconds until the token expires (the expires parameter). Once the token expires, you will need to re-run the steps above to generate a new code and access_token, although if the user has already authorized your app, they will not be prompted to do so again. If your app needs an access token with an infinite expiry time (perhaps to take actions on the user's behalf after they are not using your app), you can request the offline_access permission.