Getting Facebook Page's Ratings - ruby-on-rails

Question

I am looking to pull a public Facebook page's ratings into a Ruby on Rails app.
Essentially what I'm looking to do is run a rake task as a cron job that looks for new reviews on one particular Facebook page (the page I need will not change) and pulls them into the app. I've explored Facebook's API and the Koala gem and can't get to the page data. I'm just not sure how I can get an access token outside a browser. In addition, if I were to get the access token, it doesn't seem I can get to the ratings data without being the owner of the page.
One route I took was to send a simple GET request to the page. Something like https://graph.facebook.com/{page-id} works fine, but https://graph.facebook.com/{page-id}/ratings throws the following:
{
"error": {
"message": "(#210) Subject must be a page.",
"type": "OAuthException",
"code": 210
}
}
What is the simplest way to get to this data?

Answer 1

As mentioned in the question's comments, I needed to be authenticated as a Facebook user with admin access to the Facebook Page of interest because I need to get a token from that.
After getting access to the page, I accomplished the API call via the Koala gem. I initialized Koala with the app:
config/initializers/facebook.rb
$facebook = Koala::Facebook::OAuth.new(
"my_facebook_app_id",
"my_facebook_secret",
"my_facebook_redirect_url"
)
Since I only needed to get the token for one user in one scenario, I did so via the admin side of my app, in my facebook_controller.
In this controller action, I look for the code parameter in the route. If we don't find it, we send to the authorization url, otherwise we process and store the Facebook user token in the User model in a pre-determined and predictable record.
app/controllers/admin/facebook_controller.rb
def auth
if params[:code].present?
code = params[:code]
token = $facebook.get_access_token_info(code)
User.find_by_email('admin#example.com').update(
:fb_access_token => token['access_token'],
:fb_token_expires => token['expires'].to_i.seconds.from_now
)
redirect_to admin_dashboard_path
else
redirect_to $facebook.url_for_oauth_code(:permissions => "manage_pages")
end
end
Once I have an active token, I can acquire the page token like so:
user = User.find_by_email('admin#example.com')
user_graph = Koala::Facebook::GraphAPI.new(user.fb_access_token)
accounts = user_graph.get_connections('me', 'accounts')
page_token = accounts[0]['access_token']
page_graph = Koala::Facebook::API.new(page_token)
ratings = page_graph.get_connection('me', 'ratings')
At this point, I have the collection of ratings objects stored in the ratings variable. I can do whatever I need with these ratings at this point.
Note: In this particular case, I new the Facebook Page was the first account in the array of user accounts. This took some trial and error, but can be accomplished by iterating over the user accounts array (in this case, stored in accounts) if you can't predict the index of the desired account.

Answer 2

It seems to be a bug of Facebook Graph API. I have exactly the same problem.
I can get lists of all other objects but I do get an error when requesting /{page-id}/ratings. The JSON payload returned by Facebook Graph API is the following:
{
"error": {
"message": "(#210) Subject must be a page.",
"type": "OAuthException",
"code": 210
}
}