WebApi 2 Maximum request length exceeded

Question

Does anyone know if there is a way of catching this error?

Essentially I'm trying to implement some functionality to allow a user to upload a file from a webpage to a webapi controller.

This works fine, but if the file size exceeds the maximum size specified in the web.config the server returns a 404 error.

I want to be able to intercept this and return a 500 error along with message which can be consumed by the client.

I can't work out where to do this in WebApi as the Application_Error method I've implemented in Global.asax is never hit and it seems like IIS is not passing this through to the WebApi application.

You need to increase the maximum request size allowed. See this answer: http://stackoverflow.com/questions/288612/how-to-increase-the-max-upload-file-size-in-asp-net — Rosdi Kasim, Jul 15 '15 at 17:07
I have done already done this, but I want to be able to catch the error in instances when this has been exceeded. — llihp, Jul 15 '15 at 18:00

score 14 · Answer 1 · answered Jan 06 '18 at 23:24

Try to set IIS to accept 2GB requests(in Bytes).

<system.webServer>
  <security>
    <requestFiltering>
      <requestLimits maxAllowedContentLength="2147483648" /> // 2GB
    </requestFiltering>
  </security>
</system.webServer>

And set reasonable request size for ASP.NET app(in kiloBytes).

<system.web>
  <httpRuntime maxRequestLength="4096" /> // 4MB (default)
</system.web>

Now IIS should let requests less than 2GB pass to your app, but app will jump into Application_Error reaching 4MB request size. There you can manage what you want to return.

Anyway, requests greater than 2GB will always return 404.13 by IIS.

WebApi 2 Maximum request length exceeded

2 Answers2

Linked