Error 503 "No 'Access-Control-Allow-Origin' header"

Question

I am trying to make a connection in datasnap using ajax

my code:

                var url = 'http://cloud.nooven.com.br:12345/datasnap/rest/TServerMethods1/CriaSessao/'+cpfCnpj+'|'+usuario+'|'+senha;
                console.log(url);
                $.ajax({
                    type: "GET",
                    url: url,
                    dataType: "json",
                    success: function(data){
                        console.log('sucesso');
                    },
                    error: function(data){
                        console.log('erro');
                    }
                });

the page .html that I’m accessing on the server, so it’s like localhost on the variable url, the error that occurs is this:

XMLHttpRequest cannot load http://cloud.nooven.com.br:12345/datasnap/rest/TServerMethods1/CriaSessao/68243096000152%7CMOACIR%7C123456. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://cloud.nooven.com.br' is therefore not allowed access. The response had HTTP status code 503.

thank you.

Answer 1

As per this link CORS on Datasnap REST Server you should wear it like this:

procedure TWebModule1.WebModuleBeforeDispatch(Sender: TObject;
Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
  //Permite requisições de diferentes dominios
  Response.SetCustomHeader('Access-Control-Allow-Origin','*');
  if FServerFunctionInvokerAction <> nil then
    FServerFunctionInvokerAction.Enabled := AllowServerFunctionInvoker;
end;