NET CORE getting no 'Access-Control-Allow-Origin' when sending large JSON

Question

I created a Net core API and I'm receiving some files as byte array in the request. The problem is when the files are big, if not it works ok. I read the problem is related to json lenght and I did these following things:

I've added to the web.config

<system.webServer>
    <security>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="2147483647"></requestLimits>
      </requestFiltering>
    </security>
</system.webServer>

and

<system.web>
    <httpRuntime maxRequestLength="2147483647" />
</system.web>

Apart of that, I've added to Startup.cs

  services.Configure<FormOptions>(x =>
            {
                x.ValueLengthLimit = int.MaxValue;
                x.MultipartBodyLengthLimit = int.MaxValue;
                x.MultipartHeadersLengthLimit = int.MaxValue;
            });

Any sugestion to solve this issue?

Answer 1

By default browsers block json requests from other domains other than the page unless the json request has the Access-Control-Allow-Origin header, so you'll need to add that header to your json requests on that service or use the same domain for both.

More info here: https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS