我可以使用javascript呼叫delphi xe8 REST服务帖子吗？

Question

Getting No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access. on browser (Crome).

Server Delphi XE8 REST service exe program:

function TServerMethods.updateInsertData4(val1: string): string;
begin
  result := val1;
end;

Javascript:

xmlhttp.open("POST", "http://..hods/InsertData4", true);
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.json = false;
xmlhttp.timeout = 1000 * 10;
xmlhttp.ontimeout = function () { alert("Timed out!!!"); }
xmlhttp.onerror = function () { alert("error"); }
xmlhttp.send('data');

Answer 1

From CORS on DataSnap REST Server :

All you need to do is add a custom header in the Response before dispatching the result on the DataSnap server

procedure TWebModule1.WebModuleBeforeDispatch(Sender: TObject;
Request: TWebRequest; Response: TWebResponse; var Handled: Boolean);
begin
  //allows cross domain calls
  Response.SetCustomHeader('Access-Control-Allow-Origin','yourdomain.com');
  if FServerFunctionInvokerAction <> nil then
    FServerFunctionInvokerAction.Enabled := AllowServerFunctionInvoker;
end;

Note that the original example used '*' instead of a domain name (yourdomain.com), which would allow any third party to access your REST server.