Response.StatusCode and Internet Explorer - Display custom message?

Question

I am implementing a HttpRequestValidationException in my Application_Error Handler, and if possible, I want to display a custom message.

Now, I'm thinking about the StatusCode. In my current example, it sends a 200, which I think should not be done. I would like to send the (IMHO) more appropriate 400 Bad Request instead. However, at the same time, I would like to use Response.Write to enter a custom message. Firefox displays it properly, but IE7 gives me the Default unhelpful Internet Explorer Error Page.

On one side, I guess that Internet Explorer just assumes that everything <> 200 is simply not having any "good" content, and the RFC is not really clear here.

So I just wonder, is sending a HTTP 200 for an Error Page caused by a HttpRequestValidationException good practice or not? Are there good alternatives?

Answer 1

No, it's certainly not a good practice. 2XX status codes mean (among other things) that the request is valid. Which is just the contrary to raising a HttpRequestValidationException.

I don't know how to make IE behave correctly, sadly. A slightly better way than to send a 200 would be to redirect it to an error page, but still far from perfect.

Answer 2

Internet Explorer shows what they call a "friendly HTTP error message" when the response is 4xx or 5xx. This option can be turned off by the user in IE's Tools.Options.Advanced[Browsing] dialog.

Sending a 200 for an error page is generally bad practice. One alternative would be to have a valid "Error" page that's supposed to show error messages (so a 200 would be okay) and then use a 3xx redirect to that page.

Answer 3

An HTTP 200 Response Code does not indicate an error. It indicates that everything was OK. You should not use a 200 response code for an error.

Internet Explorer shows its "Friendly Errors" page if the response is less than 512 bytes. Here's more on this issue: http://weblogs.asp.net/scottgu/archive/2006/04/09/442332.aspx,