IVR and Facebook Introduction

We have two technologies to introduce here:

• IVR
• Facebook.NET

About the IVR, I have wrote one article to introduce it, you can explore it in this URL:IVR applications based on Voicent Gateway. Or you can learn the IVR in the Website:Voicent.

Now, we will mainly pay our attention to the Facebook.NET.

Facebook.NET

Using the code

About the code that connects to the Voicent Gateway, you can visit this article:IVR applications based on Voicent Gateway.Here I'll only post the code about Facebook.NET.

First, you need to add the Facebook controls into your applications.To use this toolkit, you will most likely want to add the FacebookWebControl component to your toolbox in Visual Studio.To do this, right-click in the area of the toolbox where you want the controls to go, and select “Choose Items” from the pop-up menu.

In the window that appears, click the “Browse…” button, locate Facebook.WebControls.dll, and open it. Click “OK”, and the controls should appear in your toolbox. If you want to add the Facebook controls for your application as well, repeat the above instructions for the appropriate Controls dll file (Facebook.Controls.dll for desktop applications).

After that, trag a FriendList control to your page:

    <div>
        <cc1:FriendList ID="FriendList1" runat="server" />
    </div>

Then, you can add some normal control in your .aspx page, like what you do in the ASP.NET web based applications:

    <div>
        <asp:Label ID="lblPhoneNumber" runat="server">PhoneNumber :</asp:Label>    
        <asp:TextBox ID="txtPhoneNumber" runat="server"></asp:TextBox>
    </div>
    <div>
        <asp:TextBox ID="txtMessage" runat="server" TextMode="MultiLine" Rows="5" 
            Columns="10" Width="240px"></asp:TextBox>
    </div>
    <div>
        <asp:Button ID="btnSendMessage" runat="server" Text="SendMessage" 
            onclick="btnSendMessage_Click" />
    </div>
        

Now, you have all the controls needed, and you should add some necessary namespaces:

using Facebook;
using Facebook.Entity;
using Facebook.Components;
using Facebook.WebControls;
using System.Collections.ObjectModel;

Let your class inherits from the baseclass CanvasIFrameBasePage:

public partial class FacebookPage : CanvasIFrameBasePage 

Put these codes in the Page_Load method:

            //Assign the API key and secret key to sign up in the Facebook.
            //These keys are got from the application you created in the Facebook.
            fbService.ApplicationKey = "2e91b1e10fde83d84f013dc5892db535";
            fbService.Secret = "73da07234bf005f7412df2ee77ff05a1";

            //Set the IsDesktopApplication property of the FacebookService to false.
            fbService.IsDesktopApplication = false;

            /* Check if we have already stored the Facebook session information or if the auth_token is in the query params.  
             * We will store what we know about the current user's Facebook Session in a server side variable.
             * We will then check that variable to see if we already have established a Facebook session on behalf of the current user.*/

            string sessionKey = Session["Facebook_session_key"] as String;
            string userId = Session["Facebook_userId"] as String;

            //When the user logins in the Facebook, the redirect back here will have the auth_token in the query params.
            string authToken = Request.QueryString["auth_token"];

            //If we have already established an session, set it to the FacebookService reference.
            if (!String.IsNullOrEmpty(sessionKey))
            {
                fbService.SessionKey = sessionKey;
                fbService.UserId = userId;
            }
            //If not, check if we have the auth_token in the query params. If we do, that means we just got called from the Facebook login page.
            else if (!String.IsNullOrEmpty(authToken))
            {
                fbService.CreateSession(authToken);

                Session["Facebook_session_key"] = fbService.SessionKey;
                Session["Facebook_userId"] = fbService.UserId;
                Session["Facebook_session_expires"] = fbService.SessionExpires;
            }
            //if neither, we need to redirect the user to the Facebook hosted login page.
            else
            {
                Response.Redirect(@"http://www.facebook.com/login.php?api_key=" + fbService.ApplicationKey + @"&v=1.0");
            }

            if (!IsPostBack)
            {
                //Use the FacebookService method to get the current user's friends.
                this.FriendList1.Friends = fbService.GetFriends();
            } 
 

You should replace the two keys using your application keys that are generated by the Facebook when you create new applications there.

fbService.ApplicationKey = "2e91b1e10fde83d84f013dc5892db535";
fbService.Secret = "73da07234bf005f7412df2ee77ff05a1"; 
 

In IE, if a parent frame has a different domain than the child page, the session data (stored in the Session object) is not preserved as a security precaution.http://wiki.developers.facebook.com/index.php/ASP.NET.

protected override void OnPreRender(EventArgs e)
{
     Response.AppendHeader("P3P", "CP=\"CAO PSA OUR\"");
     base.OnPreRender(e);
}  

In the click event of button, you can post the code that will be used to send your message.These message I've posted before, so you can visit my another article IVR applications based on Voicent Gateway or download the RAR backage that contains the whole application.

Point of Interesting

IFrames vs. FBML

When I first started looking at Facebook applications, I was quite sure FBML was the way to go for implementing the application's Canvas pages. Now I am not so sure.

FBML allows you to use a bunch of interesting Facebook user interface elements, and naturally pick up the Facebook theme. It does come at some cost: your application is constrained in terms of usage of script for example, which limits interactivity, as well as advertising. It also potentially increases latency issues as your server needs to serve up FBML, which has to be converted to HTML on Facebook's servers, before it gets rendered into the browser. To further the problem, Facebook seems to have a low threshold for timeouts, and this latency could result in an unfriendly error message, should processing on either your server or Facebook's servers take more than the allocated time.

The compelling reason for using iframes is that it allows you to do as you please within your frame, which includes the ability to run script, use your familiar Ajax framework, as well as display advertising. The downside of course is you either need to work extra hard to mimic the Facebook theme, or possibly risk a lesser than ideal level of user interface integration.

In closing, check out Facebook.NET, let me know what you think, and stay tuned for a future posts related to this. Hope to get a couple of real apps out there one of these days.

SourceCode Download