Question

I am working on integrating Omniauth with my new Facebook application, and I am looking through the rather sparse documentation to understand if it gives simple ways to access the graph API… I am moving from Koala which was pretty simple.

Has anyone out there used Omniauth for this yet? I want to get photos from the users’ albums, and sort and get the unique URLs for them.

Answer 1

So I wasn’t able to get fb_graph to work properly – I am still a noob having been a Ruby On Rails developer for a total of about 8-10 weeks, and therefore don’t have an instinct for what must be obvious problems to other folks.

However I found this great little blog post which outlines a simple facebook client and shows clearly how it all plugs together. I found an issue with it picking up the me/picture object as Facebook returns an http302 not http200 but that was easily worked around with the help of the author. Check it out: http://bnerd.de/misc/ruby-write-basic-client-for-facebook-graph-api/

I am now using Omniauth for the simplicity of the login/signup interaction based on this walkthrough here: blog.railsrumble.com/blog/2010/10/08/intridea-omniauth and with the token I get from that I am using this simple FBClient from the bnerd reference above to access the Graph API. Hope what I found helps others.

…here’s my version of bnerd’s code and it worked for me:

    class FBClient

      def initialize(app, access_token = nil)
        @app = app
        @access_token = access_token
      end

      # request permission(s) from user
      def request(perms)
        #create a random verifier to identify user on fb callback
        verifier = (0...10).map{65.+(rand(25)).chr}.join
        uri = "https://graph.facebook.com/oauth/authorize?client_id=#{@app.app_id}&redirect_uri=#{@app.connect_url}?verifier=#{verifier}&scope=#{perms}"

        request = { :verifier => verifier, :uri => uri }
        return request

      end

      def connect(code, verifier)

        uri = URI.parse("https://graph.facebook.com/oauth/access_token?client_id=#{@app.app_id}&redirect_uri=#{@app.connect_url}?verifier=#{verifier}&client_secret=#{@app.secret}&code=#{CGI::escape(code)}")
        http = Net::HTTP.new(uri.host, uri.port)
        http.use_ssl = true

        request = Net::HTTP::Get.new(uri.path + "?" + uri.query)
        response = http.request(request)     
        data = response.body

        return data.split("=")[1]
      end

      # get, post
      def get(path, params = nil)
        uri = URI.parse("https://graph.facebook.com/" + path)
        http = Net::HTTP.new(uri.host, uri.port)
        http.use_ssl = true

        if params.nil?
          params = Hash.new
        end

        if params["access_token"].nil? 
          params["access_token"] = @access_token unless @access_token.nil?
        end

        request = Net::HTTP::Get.new(uri.path) 
        request.set_form_data( params )
        request = Net::HTTP::Get.new(uri.path + "?" + request.body)

        return response = http.request(request)
      end

      def post(path, params = nil)
        uri = URI.parse("https://graph.facebook.com/" + path)
        http = Net::HTTP.new(uri.host, uri.port)
        http.use_ssl = true        

        if params.nil?
          params = Hash.new
        end

        if params[:access_token].nil?
          params[:access_token] = @access_token unless @access_token.nil?
        end

        request = Net::HTTP::Post.new(uri.path) 
        request.set_form_data( params )
        request = Net::HTTP::Post.new(uri.path + "?" + request.body)

        response = http.request(request)
        response.code == "200" ? feed = JSON.parse(response.body) : raise("Sorry, an error occured. #{response.body}")
        return feed
      end
    end

I am sure someone more experienced than I could improve this – I was about 10 weeks into learning Ruby (and my first programming since Fortran and Pascal at university in the early 90s!).