upload image in ckeditor4 and netcore

inside ckeditor4 folder add this inside config.js

CKEDITOR.editorConfig = function(config) {
  // other config
  config.removeDialogTabs =
    "image:advanced;image:Link;link:advanced;link:upload"
  config.filebrowserImageUploadUrl = "<Address-to-controller>"
}

you can add static address for uploading pic like: /Admin/Upload or dynamic depend on when it happen like ?handler=UploadImage in razor page framework.

for prevent 400 error, Forgery problem we must do two things. in Startup.cs file add this line:

public void ConfigureServices(IServiceCollection services)
{
  // other things
  services.AddAntiforgery(o => o.HeaderName = "XSRF-TOKEN");
}

every time we use ckeditor4 in cshtml file add this things.

// in form or other place
@Html.AntiForgeryToken()

// when we called ckeditor4
<script>
  CKEDITOR.replace('City_Description', {
    language: 'fa',
    fileTools_requestHeaders: {
      "XSRF-TOKEN":$('input:hidden[name="__RequestVerificationToken"]').val()
    }
  });
</script>