how to get a valid response from a php web service on GWT - gwt

Question

I'm trying to get data from a php web service (that I've put in my localhost - tested and works fine) in the client side of my GWT application.
I've tried to use the following package com.google.gwt.http.client.* it looks like the code works fine but the response is always 0, it's highly likely to be a corss problem but I still can't figure how to solve it even though I've tried to use requestBuilder.setHeader(..);
here's the code I'm working on:
String url = "http://localhost/geoTrackerTest.php?id=15";
RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, URL.encode(url));
requestBuilder.setHeader("Access-Control-Allow-Origin", "http://localhost");
requestBuilder.setHeader("Access-Control-Allow-Methods", "POST, GET, UPDATE, OPTIONS");
requestBuilder.setHeader("Access-Control-Allow-Headers", "x-http-method-override");
try {
Request request = requestBuilder.sendRequest(null, new RequestCallback() {
public void onError(Request request, Throwable exception) {
GWT.log("Error: "+exception.getMessage());
}
public void onResponseReceived(Request request, Response response) {
if (200 == response.getStatusCode()) {
GWT.log("response: "+response.getText());
} else {
GWT.log("response code: "+response.getStatusCode());
}
}
});
} catch (RequestException e) {
GWT.log("Request Exception: "+e.getMessage());
}
I'm still getting 0 as a response.

Answer 1

You will need to set the header in response from server side (not from the GWT client side), then you can make Cross Site Requests from GWT RequestBuilder. Something like this on server side:
Response.setHeader("Access-Control-Allow-Origin","http://localhost");
If you only need to send GET requests, you can use JSONP (http://www.gwtproject.org/javadoc/latest/com/google/gwt/jsonp/client/JsonpRequestBuilder.html) instead to send cross domain requests, without headers setting on server side.