Base URL for a GWT App

Question

I'm developing a GWT App which generates reports for download. When I launch in Eclipse it has an URL like this:

http://127.0.0.1:8888/MyApp.html

But when I package my app for deployment in a web server (i.e. Tomcat) my URL is like this:

http://localhost:8080/MyApp/MyApp.html

Is there any way to get the app's base URL? Like http://localhost:8080/MyApp/ in the second case?

Answer 1

Client side:

GWT.getHostPageBaseURL();

or

GWT.getModuleBaseURL();

Server side you can get the URL of any servlet from the HttpServletRequest by using this simple method:

public static String getBaseUrl( HttpServletRequest request ) {
    if ( ( request.getServerPort() == 80 ) ||
         ( request.getServerPort() == 443 ) ) {
      return request.getScheme() + "://" +
             request.getServerName() +
             request.getContextPath();
    } else {
      return request.getScheme() + "://" +
             request.getServerName() + ":" + request.getServerPort() +
             request.getContextPath();
    }
}

Answer 2

For client side you can use Window.Location

For example:

public static String getUrlString(String path) {
    UrlBuilder urlBuilder = new UrlBuilder();
    urlBuilder.setHost(Window.Location.getHost());
    urlBuilder.setPath(path);

    String port = Window.Location.getPort();
    if (!port.isEmpty())
        urlBuilder.setPort(Integer.parseInt(port));

    return urlBuilder.buildString();
}

Another approach is to use GWT Dictonary. Here you include a snippet of JavaScript in your host HTML page to set the value:

<script type="text/javascript" language="javascript">
  var location = { baseUrl: "http://localhost:8080/myapp" };
</script>

Then load the value into the client side with GWT Dictionary:

   Dictionary theme = Dictionary.getDictionary("location");
   String baseUrl = theme.get("baseUrl");

To use this you would have to change the HTML host page for your local and production instances.