Module: Koala::Facebook::RealtimeUpdateMethods

Included in:
RealtimeUpdates
Defined in:
lib/koala/realtime_updates.rb

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

note: to subscribe to real-time updates, you must have an application access token



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# File 'lib/koala/realtime_updates.rb', line 8

def self.included(base)
  # make the attributes readable
  base.class_eval do
    attr_reader :app_id, :app_access_token, :secret
    
    # parses the challenge params and makes sure the call is legitimate
    # returns the challenge string to be sent back to facebook if true
    # returns false otherwise
    # this is a class method, since you don't need to know anything about the app
    # saves a potential trip fetching the app access token
    def self.meet_challenge(params, verify_token = nil, &verification_block)
      if params["hub.mode"] == "subscribe" &&
          # you can make sure this is legitimate through two ways
          # if your store the token across the calls, you can pass in the token value
          # and we'll make sure it matches
          (verify_token && params["hub.verify_token"] == verify_token) ||        
          # alternately, if you sent a specially-constructed value (such as a hash of various secret values)
          # you can pass in a block, which we'll call with the verify_token sent by Facebook
          # if it's legit, return anything that evaluates to true; otherwise, return nil or false
          (verification_block && yield(params["hub.verify_token"]))
        params["hub.challenge"]
      else
        false
      end
    end
  end
end

Instance Method Details

#api(*args) ⇒ Object

same as GraphAPI



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# File 'lib/koala/realtime_updates.rb', line 77

def api(*args) # same as GraphAPI
  response = super(*args) do |response|
    # check for subscription errors
    if response.is_a?(Hash) && error_details = response["error"]
      raise APIError.new(error_details)
    end
  end

  response
end

#initialize(options = {}) ⇒ Object 



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# File 'lib/koala/realtime_updates.rb', line 36

def initialize(options = {})
  @app_id = options[:app_id]
  @app_access_token = options[:app_access_token]
  @secret = options[:secret]
  unless @app_id && (@app_access_token || @secret) # make sure we have what we need
    raise ArgumentError, "Initialize must receive a hash with :app_id and either :app_access_token or :secret! (received #{options.inspect})"
  end
  
  # fetch the access token if we're provided a secret
  if @secret && !@app_access_token
    oauth = Koala::Facebook::OAuth.new(@app_id, @secret)
    @app_access_token = oauth.get_app_access_token
  end
end

#list_subscriptions ⇒ Object 



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# File 'lib/koala/realtime_updates.rb', line 73

def list_subscriptions
  api(subscription_path)["data"]
end

#subscribe(object, fields, callback_url, verify_token) ⇒ Object

subscribes for realtime updates your callback_url must be set up to handle the verification request or the subscription will not be set up developers.facebook.com/docs/api/realtime



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# File 'lib/koala/realtime_updates.rb', line 54

def subscribe(object, fields, callback_url, verify_token)
  args = {
    :object => object, 
    :fields => fields,
    :callback_url => callback_url,
    :verify_token => verify_token
  }
  # a subscription is a success if Facebook returns a 200 (after hitting your server for verification)
  api(subscription_path, args, 'post', :http_component => :status) == 200
end

#unsubscribe(object = nil) ⇒ Object

removes subscription for object if object is nil, it will remove all subscriptions



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# File 'lib/koala/realtime_updates.rb', line 67

def unsubscribe(object = nil)
  args = {}
  args[:object] = object if object
  api(subscription_path, args, 'delete', :http_component => :status) == 200
end