Chao Lam

YouTube wins case against Viacom.

I recently implemented Facebook’s  real-time updates api. Since I couldn’t find a decent tutorial and ran into a few small roadblocks, I thought I’d share what I learnt.

This tutorial basically gets real-time updates of any name changes for users of your FB app. I’m going to use examples with Curl – since that’s like the swiss knife of http programming.

Step 1 – get access token

curl https://graph.facebook.com/oauth/access_token?client_id=<app-id>&client_secret=<app-secret>&type=client_cred

Note you can also use your api key (which I accidentally did!)

This should return a 40 over character long access token, the initial part looks suspiciously like your app id e.g.

access_token=222868257269|34567890123456789012345678901

Step 2 – Check if access token is working (optional)

With access token in hand, you can now query what real-time updates your app is already subscribed to. Real-time updates API is RESTful; so a HTTP Get returns your current subscriptions. e.g.

curl "https://graph.facebook.com/<appid>/subscriptions?access_token=<access token from  step (1)>"

This result is JSON-encoded. If you’re just starting out, you would have no subscriptions:

{"data":[]}

If you somehow goofed up, a JSON-encoded error is returned:

{"error":{"type":"Exception","message":"xxx"}}

Note: api key can’t be used instead of app id here!

Step 3 – Submit your update

This is the meat of the call. You are to submit a HTTP POST with Form-like arguments (don’t POST with JSON-encoded arguments as I had wrongly assumed)

curl -F 'object=user' \
-F 'callback_url=<callback url you have to implement>' \
-F 'fields=name' \
-F 'verify_token=<secret token>' \
"https://graph.facebook.com/<appid>/subscriptions?access_token=<access token from (1)"

curl should return “null”. Go back to Step (2) to check if all you entered was recorded by Facebook.

Hope this helps!