Finding out if a Facebook page is liked by a user. Using the Facebook C# SDK
I'm trying to build a Facebook 'fangate' tab or 'reveal' tab for a Facebook page.
You know how it goes - when a user visits the page, they are shown one bit of content if they haven't yet clicked 'Like' and another once they have.
I'm not a PHP guy so I'm attempting to do this with the Facebook C# SDK (http://facebooksdk.codeplex.com) in Visual Studio 2010. I'm fairly new to .NET too so I'm not doing so well with this!
I have to admit I've been cutting and pasting code from all over the place to get this to work and I think I'm almost there but I'm not getting this error:
Invalid signed request.
Line 82: var DecodedSignedRequest = FacebookSignedRequest.Parse(current, FacebookWebContext.Current.SignedRequest.Data.ToString());
Here's my code:
var settings = ConfigurationManager.GetSection("facebookSettings");
var current = settings as IFacebookApplication;
var DecodedSignedRequest = Facebo开发者_JAVA技巧okSignedRequest.Parse(current, FacebookWebContext.Current.SignedRequest.Data.ToString());
dynamic SignedRequestData = DecodedSignedRequest.Data;
var RawRequestData = (IDictionary<string, object>)SignedRequestData;
string currentFacebookPageID = current.AppId;
bool currentFacebookPageLiked = false;
if (RawRequestData.ContainsKey("page") == true)
{
Facebook.JsonObject RawPageData = (Facebook.JsonObject)RawRequestData["page"];
if (RawPageData.ContainsKey("id") == true)
currentFacebookPageID = (string)RawPageData["id"];
if (RawPageData.ContainsKey("liked") == true)
currentFacebookPageLiked = (bool)RawPageData["liked"];
}
if (currentFacebookPageLiked)
{
//Do some stuff for fans
}
else
{
//Do some stuff for non-fans
}
All the Facebook settings are in my web.config file and I have checked that the AppID and AppSecret are correct.
Can anyone offer me any insight into this issue please? Is there a better way of doing this that I've not yet found?
Many thanks in advance for any help.
OK, I've sorted it out - but I'm not sure why. I have a feeling that the Facebook C# SDK screws around with the signed request in some way. If I get the signed request using Request.Forms["signed_request"] it all seems to work.
I'll share my working code in the hope that it will help others with the same problem.
//Pull in the facebook app settings from the web.config file
var settings = ConfigurationManager.GetSection("facebookSettings");
var current = settings as IFacebookApplication;
//Set up some stuff for later
string currentFacebookPageID = current.AppId;
bool currentFacebookPageLiked = false;
//Get the signed request
FacebookSignedRequest SignedRequest = FacebookSignedRequest.Parse(current, Request.Form["signed_request"]);
dynamic SignedRequestData = SignedRequest.Data;
//extract what we need from the request
var RawRequestData = (IDictionary<string, object>)SignedRequestData;
//Check to see if we've got the data we need
if (RawRequestData.ContainsKey("page") == true)
{
//We do, lets examine it and set the boolean as appropriate
Facebook.JsonObject RawPageData = (Facebook.JsonObject)RawRequestData["page"];
if (RawPageData.ContainsKey("id") == true)
currentFacebookPageID = (string)RawPageData["id"];
if (RawPageData.ContainsKey("liked") == true)
currentFacebookPageLiked = (bool)RawPageData["liked"];
}
if (currentFacebookPageLiked)
{
//Do some stuff for fans
lblName.Text = "Hi " + result.first_name + " - You are a fan";
}
else
{
//Do some stuff for non-fans
lblName.Text = "Hi " + result.first_name + " - please click the like button";
}
This is the code i used and it worked great for me.
protected bool IsPageLiked()
{
var current = ConfigurationManager.GetSection("facebookSettings")
as IFacebookApplication;
dynamic signedRequest = FacebookSignedRequest.Parse(current, Request);
try
{
return signedRequest.Data.page.liked;
}
catch (Exception)
{
return false;
}
}
精彩评论