use fbsdk swift to get fb user email

fbsdk.swift

        let login = FBSDKLoginManager()
        login.logInWithReadPermissions([ "email" ], fromViewController: self) { (result: FBSDKLoginManagerLoginResult!,error: NSError!) -> Void in
            if (error != nil){
                SVProgressHUD.showErrorWithStatus(error.localizedDescription)
            } else  if (result.isCancelled) {
                SVProgressHUD.showWithStatus("Canceled")
            } else {
                self.logger.info("fb token: \(result.token.tokenString)")
                let params = ["fields" : "email,name"]
                FBSDKGraphRequest(graphPath: "me", parameters: params).startWithCompletionHandler({ (connection: FBSDKGraphRequestConnection!, result: AnyObject!, error: NSError!) -> Void in
                    
                    if error != nil {
                        self.logger.error("error:  \(error)")
                    } else {
                        self.logger.info("fb email:  \(result)")
                    }
                })
                
            }
        }