Facebook login with redirect URL_问答_开发者_运维开发者技术经验分享

开发者 https://www.devze.com 2023-03-30 19:53 出处：网络

I am developing a Facebook canvas appliaction, and I am trying to do the following, which is standard in many applications.

User arrives on my application page.
If he has not granted the necessary permissions, he is redirected to a page where he can (optionally authenticate) and accept the permissions, and
finally redirected back t开发者_Python百科o my facebook application page.

As far as I understand, this is achieved by redirecting the user to the OAuth dialog, on

http://www.facebook.com/dialog/oauth/?
  scope=PERMISSIONS&
  client_id=CLIENT_ID&
  redirect_uri=MY_CANVAS_URL&
  response_type=token

The problem is that Facebook will not allow a redirect from inside an iframe, for security reasons. It only allows redirects to what I declare as site URL on the application settings page. In my case I have set that to the URL of the application on Facebook, since that is what I put as redirect_uri (and it works).

So, instead of being able to see the authentication dialog, the user is presented only a link to it. A kind of workaround is to issue the redirect with javascript, by manually settings top.location. But this is not a real solution, since part of the site already shows before Javascript redirects, and I get an annoying flicker.

What is the correct way to obtain this flow?

You need to use:

top.location.href=myAuthUrl;

There is a tutorial on canvas auth here: https://developers.facebook.com/docs/appsonfacebook/tutorial/#auth

you can use a validation page before you redirect to your app home page . something like this :

    <html>
    <head>
    <script src="facebook_javascript_api_file_src"></script>
    </head>
    <body>
        <div id="fb-root"></div>
        <script>
        function verify(){
        FB.init({
                appId:"app_id",
                status:true,
                cookie:true,
                xfbml:true
                }

        );

        FB.getLoginStatus(function(response){
                    if(response.session){
                         top.location.href="url to your app home page";
                    }
                    else{
                         top.location.href="https://www.facebook.com/dialog/  
         oauth?client_id=APP_ID&redirect_uri=redirect_url&scope=email,read_stream";
                     }
        })
    }
        verify();
        </script>
    </body>
    </html>