facebook permissions - public pages

Question

My question is about permissions. Do I need permissions from the user for public pages?

Here is my set up

1. I created an app on Facebook, and through that I got the clientId and clientSecret
2. Using these credentials. I got a access token, which doesn't expire at all. I would love to hear explanation on that!
3. I have a server that's running and downloading data for those public pages through FQL
4. My server provides REST apis to be consumed by my app
5. In my iOS app, I am calling the apis from my server to get the data it has downloaded.

Question:
In my iOS app, do I need the user to login to Facebook? Because I have all the data with me, so there is no need for the user to login. Unless I ask for the user to start posting things, for which I would need permissions. But when just reading data which my server downloaded through its own credentials, is it ok to show that data without asking the user to login or ask for permissions. Again, these are public pages.

Answer 1

Using these credentials. I got a access token, which doesn't expire at all. I would love to hear explanation on that!

You must be talking of the App Access Token, yes, it never expires. It's the user/page access token that expires. App access token has limited powers. You can read more about access token here: Access Tokens

do I need the user to login to Facebook?

If you app is just showing the data of the public pages, nothing to do specific to the user, you don't need to implement login etc. At later, if you require to perform some user-specific actions, you might have to use loginand get the user access token (that expires!) to perform those actions.