public FacebookInstance GetInstance(FacebookConfigElement elem, NameValueCollection paramCollection)
{
string signed_request = paramCollection["signed_request"].Default().DecodeUrl();
FacebookInstance instance = null;
string json = null;
if (!signed_request.isEmpty())
{
#region check the signature of the signed request
string hash = signed_request.Part('.', 0).Decode64();
json = signed_request.Part('.', 1).Decode64();
string evidence = signed_request.Part('.', 1).HashForKey(elem.appSecret);
if (hash.NotEquals(evidence))
throw new FormatException("Invalid Signature");
#endregion
}
instance = new FacebookInstance(elem, json);
instance.HttpParameters = paramCollection.ToDictionary();
return instance;
}
internal FacebookInstance(FacebookConfigElement elem, string json=null)
{
Connected = false;
page = new Page(null);
user = new User(null);
HttpParameters = new Dictionary<string,string>();
AppId = elem.appId;
AppName = elem.key;
AdminId = elem.adminId;
PageId = elem.pageId;
PageName = elem.pageName;
PageUrl = elem.pageUrl;
if (json != null)
{
JavaScriptSerializer jss = new JavaScriptSerializer();
jss.RegisterConverters(new JavaScriptConverter[] { new DynamicJsonConverter() });
var fb = jss.Deserialize(json, typeof(object)) as dynamic;
string code = fb.algorithm;
if (code.NotEquals("HMAC-SHA256"))
throw new ArgumentException("Expected HMAC-SHA256");
Connected = true;
try { app_data = fb.app_data; }
catch { }
algorithm = fb.algorithm;
try { expires = fb.expires.ToString(); }
catch { }
issued_at = fb.issued_at.ToString();
try { oauth_token = fb.oauth_token; }
catch { }
page = new Page(fb.page);
user = new User(fb);
}
}
protected override object GetElementKey(ConfigurationElement element)
{
FacebookConfigElement obj = (FacebookConfigElement)element;
return(obj.key);
}
