Question

I send POST request to create some data resource on server. I get Response Code 201 – all is OK. But I also need to get 2 headers from the response. Those headers contain attributes of the created resource. I did not find the way how to do it using ConnectionRequest’s API.

The class has readHeaders(connection) and getHeader(connection) protected methods. But I could not use them when I got the response – got an exception.

My code example is shown below:

ConnectionRequest reqresp = new ConnectionRequest () {
    protected  void buildRequestBody (java.io.OutputStream os) {
    Logger.inst ().write ("buildRequestBody");
        final String body = "Dummy Request Body"; // necessary for my request
        try {
            os.write (body.getBytes () );
        }
        catch (Exception ex) {
            final String errMsg = ex.toString ();
            Logger.inst ().write (errMsg);
            throw new RuntimeException (errMsg);
        }
    }

    protected void readResponse (InputStream input) throws IOException  {
        // Actually this method will not be called.
        Logger.inst ().write ("readResponse");
        String respText;
        try {
            respText = Util.readToString (input);
        }
        catch (Exception ex) {
            final String errMsg = ex.toString ();
            Logger.inst ().write (errMsg);
            throw new RuntimeException (errMsg);
        }
        Logger.inst ().write (respText);
    }
};
reqresp.setUrl ("MY SERVER URL");
reqresp.setPriority (ConnectionRequest.PRIORITY_HIGH);
reqresp.setPost (true);
reqresp.addRequestHeader ("header1", "val1");
reqresp.addRequestHeader ("Content-type", "application/json");
reqresp.addResponseCodeListener (new ActionListener () {
        public void actionPerformed (ActionEvent ae) {
            Logger.inst ().write ("ResponseCodeListener:");
            Logger.inst ().write (ae.toString () );
            if (ae instanceof NetworkEvent) {
                NetworkEvent evt = (NetworkEvent)ae;
                Logger.inst ().write ("message: " + evt.getMessage () );
                Logger.inst ().write ("response code: " + evt.getResponseCode () );
            }
        }
    });
reqresp.addResponseListener (
    new ActionListener () {
        public void actionPerformed (ActionEvent ae) {
            Logger.inst ().write ("ResponseCodeListener:");
            Logger.inst ().write (ae.toString () );
            if (ae instanceof NetworkEvent) {
                NetworkEvent evt = (NetworkEvent)ae;
                Logger.inst ().write ("message: " + evt.getMessage () );
                Logger.inst ().write ("response code: " + evt.getResponseCode () );
            }
        }
    }
);

NetworkManager.getInstance ().addToQueue (reqresp);

Answer 1

I could not perform the task using the LWUIT’s IO. But I did it easily using the MIDP’s HTTPConnection and met no problems.

One small comment about the MIDP’s HTTPConnection API. It’s synchronous. So, I did not want to use it in the main GUI thread. Moreover, the API is low-level. So, I had to implement some kind of wrapper to hide the details and to execute HTTP request asynchronously in a separate thread.

Now one comment about the LWUIT’s IO ConnectionRequest class. I found it programmer-unfriendly. It represents both a request and response. So, it’s not clear what the methods are related to the request and what to the response.