Why http post on android fails over 3g?

Question

i have an android application that makes an HTTP post request to a server containing some NameValuePairs, and It works just fine over any wifi network, but when i use the same http post over 3g, the server gets a http request with an empty body. Here is the code for the request

            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
                    3);
            nameValuePairs.add(new BasicNameValuePair("Name", params[0]));
            nameValuePairs.add(new BasicNameValuePair("DNI", params[1]));
            nameValuePairs.add(new BasicNameValuePair("Token", params[2]));

            URL url = new URL(URL_SERVER);
            HttpURLConnection conn = (HttpURLConnection) url
                    .openConnection();
            conn.setReadTimeout(30000);
            conn.setConnectTimeout(50000);
            conn.setRequestMethod("POST");
            conn.setDoInput(true);
            conn.setDoOutput(true);

            OutputStream os = conn.getOutputStream();
            BufferedWriter writer = new BufferedWriter(
                    new OutputStreamWriter(os, "UTF-8"));
            writer.write(getQuery(nameValuePairs));
            writer.flush();
            writer.close();
            os.close();

            conn.connect();
            int responseCode = conn.getResponseCode();
            BufferedReader in;
            if (responseCode == 404)
                in = new BufferedReader(new InputStreamReader(
                        conn.getErrorStream()));
            else
                in = new BufferedReader(new InputStreamReader(
                        conn.getInputStream()));
            String inputLine;
            StringBuffer response = new StringBuffer();

            while ((inputLine = in.readLine()) != null) {
                response.append(inputLine);
            }
            in.close();

Here is the code for the getQuery method

private String getQuery(List<NameValuePair> params)
        throws UnsupportedEncodingException {
    StringBuilder result = new StringBuilder();
    boolean first = true;

    for (NameValuePair pair : params) {
        if (first)
            first = false;
        else
            result.append("&");

        result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
        result.append("=");
        result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
    }

    return result.toString();
}

Any idea why this happens?

I have new info. I made a form to send the http post over the web browser. that form works great and sends perfectly the body over 3g on Windows phone and over wifi. But when I try to use the chrome of the android phone over 3g to send the http post, it arrives empty, and also if I try to send the http post from one computer connected to a hotspot of my android phone it fails. When i try with the same computer connected to a wifi network, no problem at all. This is so weird. Ideas?

Answer 1

Solved, the problem was that the server didn't read properly the requests that had multiple tcp datagrams, and looks like android split the tcp datagrams over 3g