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How does the execption handling work with jquery and asp.net mvc?

Answer 1

+1 A:

It sounds like you are seeing an exception which comes with a stracktrace (set debug to true in web.config) it should tell you the type of exception (perhaps you are catching the wrong type like David Andres suggests) and it will also contain the line numbers from the stack indicating where it's being thrown.

p.s. there is no question or even question mark in your "question" so I assume this is what you are looking for.

olle 2009-09-12 21:25:54

It tells me the type of exception that is being thrown but no line numbers or none that look line numbers some of the lines have like +81 and stuff like that.

chobo2 2009-09-12 21:36:57

About Stack traces: read the exception text from the bottom up. The very last method listed is actually the first method called. This is a trace of the execution path that lead to the failure, so somewhere within the initial call to ExecuteStep a call to Execute() was made, and in that method ProcessRequest was called, and so on and so forth.

David Andres 2009-09-12 21:51:32

Answer 2

+1 A:

I believe your try/catch block is in the action method, but that the failure occurs before the action executes. Specifically, I think the failure is in the AuthorizeCore method where you make the GetRolesForUser call.

This code may be provided by MVC, and it wouldn't suprise me if adequate safety measures weren't put in place for data access. Worst case scenario: you may need to create a custom Authorize attribute and override its AuthorizeCore method or override the OnAuthorization method of the Controller you're extending.

To create your own Authorize attribute:

public class MyAuthorizeAttribute: AuthorizeAttribute
{
  protected override bool AuthorizeCore(HttContextBase httpContext)
  {
    var isAuthorized = //your code here;
    return isAuthorized;
  }
}

You can now use this attribute in place of Authorize, as in:

[MyAuthorize(Roles = "Admin")]
public ViewResult MyAction()
{
  ...
}

To override the Controller's OnAuthorization method:

protected void OnAuthorization(AuthorizationContext filterContext)
{
  var isAuthorized = //your code here;

  if(!isAuthorized) 
  {
    filterContext.Result = new HttpUnauthorizedResult();
  }
}

EDIT: This gets around the issue of a messy exception being sent back to the client. What it doesn't help with is your ability to catch this exception and return something meaningful back (e.g., the database is down). The problem is that we can capture the fact that the database is down in the Authorize method, which is where we should indicate that the user is not authorized. However, because the user is not authorized the action method will not fire, and so your ability to throw something back to the client is limited.

For lack of a better way of handling this, you may want to allow the user in via the OnAuthorizationMethod, but as you're doing this you can set a class property to a known value. When you enter the action method, you can inspect this value and act at that point. It's a hack, and your mileage will vary...

Alternatively, you can add a [HandleError(View="...")] attribute to your action method. I don't know if this while fire as a result of an error in the Authorize step and this will not return a JSONResult and you intended.

David Andres 2009-09-12 21:44:31

Hmm I guess I will leave it for now. Ya I know the handleError but I heard it does not with elmah out of the box. I saw a post on this site about how to get them to both to work together but I did not fully get it.

chobo2 2009-09-12 22:56:50

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How does the execption handling work with jquery and asp.net mvc?

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