I'm developing my app now,and use REST api mode, but i can't find which api can get current userid (current viewer).
what shall i do?

best regard.
Jackie.

Use makeRequest in gadget.xml to call a page of yours, you'll have the current userid in the request params:

var params = {};
params[gadgets.io.RequestParameters.AUTHORIZATION] = gadgets.io.AuthorizationType.SIGNED;
params["OAUTH_SERVICE_NAME"] = "HMAC"; //This is the critical part which forces the use of HMAC
params[gadgets.io.RequestParameters.CONTENT_TYPE] = gadgets.io.ContentType.JSON;
params[gadgets.io.RequestParameters.METHOD] = gadgets.io.MethodType.GET;

var url = document.getElementById('url').value + "?container_view=" + gadgets.views.getCurrentView().getName();
gadgets.io.makeRequest(url, showResponse, params);