ASP.NET MVC. Check if user is authorized from JavaScript

问题

I'm using ASP.NET MVC Framework 3 and Forms Authentication. I know, how to check on servers side, if the user is authorized for some action (with [Authorize]) and I know, how to check this within an action or a view (with User.Identity.IsAuthenticated or other members of 'User').

What I'm trying to do - is to define some JavaScript code, that will be executed differently, depending if the user is authorized.

Consider such script on the page:

<script>
 function Foo(){
  if(userAuthorized)
   alert("You\'re in the system");
  } else {
   alert("You\'re not authorized");
  }
<script>

Function Foo() is triggered by some event, say click. And I'd like to have an ability to check, if user is authorized, on clients side.

The best solution I've came up with is to actually render global variables initialization in view. Like this:

@if(User.Identity.IsAuthenticated)
{
 <script>
  var userAuthorized = true;
 </script> 
}
else
{
 <script>
  var userAuthorized = false;
 </script> 
}

But it doesn't seems to me as a good approach. Are there any other ways? Thanks in advance.

PS: This is a usability issue, of course I'm doing necessary checks on server.

回答1:

I like the idea in @Gaby's comment, though I am not sure whether that's doable since I don't have the whole picture on your project.

At the very least you can simplify your code by doing...

<script>
  var userAuthorized = @User.Identity.IsAuthenticated.ToString().ToLower();
</script>

回答2:

Another couple of options would be to use a custom HTML data- attribute or create a simple ajax request that asks the server if the user is authenticated.

来源：https://stackoverflow.com/questions/5666270/asp-net-mvc-check-if-user-is-authorized-from-javascript