.NET Core 3 & IIS Express maxAllowedContentLength not working - file-upload

Question

I have a JavaScript application which is posting files to .NET Core 3 Web API.
Web API project works locally on IIS Express.
Files below 30 MB are working fine, but large files does not get through.
Here I tried;
1- Update %userprofile%\my documents\iisexpress\config\applicationhost.config file with new maxAllowedContentLength value.
2- Add RequestSizeLimit attribute to Controller Action.
Is there anything else I am missing here?

Answer 1

I had the same problem (since .NET Core 3), and found a workaround first, then a proper solution.
Workaround: in your web.config file, use "AspNetCoreModule" instead of "AspNetCoreModuleV2", but you no longer benefit from the advantages of the new module.
A solution: add this to your startup.cs file
services.Configure<IISServerOptions>(options =>
{
options.MaxRequestBodySize = int.MaxValue; // or your desired value
});
I found this info here: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/iis/?view=aspnetcore-3.1#application-configuration. IIS options > In-process hosting model, then attribute "MaxRequestBodySize". For this to work, you still need to have your web.config configured with something like this:
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="2147483647" /> //or your desired value
</requestFiltering>
</security>
Hope it helps!

Answer 2

For NetCore 3.1
1° you can add the attributes :
[RequestSizeLimit(300000000)] // for 300Mb files
[RequestFormLimits(MultipartBodyLengthLimit = 300000000)]
2° in web config add the follow line:
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="300000000"
</requestFiltering>
</security>