I am writing a simple procedure that automatically makes a facebook post. From what I understand, I need to have a "user access token" to do this. I am using Koala (but the philosophy is similar for other libraries). Anyway, I create a new OAuth account:
@oauth = Koala::Facebook::OAuth.new(app_id, app_secret, callback_url)
The koala instructions then become somewhat unclear. The next two lines are:
@oauth.url_for_oauth_code # generate authenticating URL
@oauth.get_access_token(code) # fetch the access token once you have the code
Where does the "code" variable come from? It doesn't say in the documentation. Also, does the "get_access_token" method get an "app access token" or a "user_access_token"? The method name is not clear. I tried going to the url that the [url_for_oauth_code] method gave me, but it gives me no code! Where does the "code" variable come from?
On the front page of Koala it states you need to go through the OAuth process described at http://developers.facebook.com/docs/authentication/ (this is an old link but the content within is valid)
Specifically
@oauth.url_for_oauth_code
https://github.com/arsduo/koala/blob/master/lib/koala/oauth.rb#L85 Generates a URL that you need to direct the user to based on the repo it's something like
https://www.facebook.com/dialog/oauth?
client_id={app-id}&
redirect_uri={redirect-uri}&
scope=email
Based on the documentation https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow/v2.2#login, when the response_type is omitted the default response type is code. So the above is equivalent to
https://www.facebook.com/dialog/oauth?
client_id={app-id}&
response_type=code&
redirect_uri={redirect-uri}&
scope=email
So on redirect to redirect-uri, this URL will be appended with the code param which you must handle then supply to
@oauth.get_access_token(code)
The access token is a user access token.