Every second HttpsUrlConnection request of my static method fails on Android

Question

I'm having a big issue with a static HTTPS connection method. Every second request fails and HttpsUrlConnection.getResponseCode() returns -1. So every second call works well, returning data as expected.

It's the method of a static class I'm using in different corners of my application. I would guess there is anything I don't clean up correctly when the method returns the first time and that whatever causes a problem might get destroyed through a second call of the method. But I'm having a hard time finding any clues.

I'm currently using this class to talk to hosts with invalid SSL certificates. Not going to use this in the final version of the app, but right now I need to save money. ;)

public static String makeInvalidHTTPSRequest(String url, String[] postVars, String userName, String userPass, Context ctx) throws MalformedURLException, IOException, NoSuchAlgorithmException, KeyManagementException {
    StringBuffer sb = new StringBuffer();
    String serverAuth = null;
    String serverAuthBase64 = null;
    StringBuffer urlParameters = new StringBuffer();
    InputStream rcvdInputStream = null;

    if (checkNetworkAvailability(ctx) == false) {
        GeneralMethods.writeLog("Network unavailable", 1, GeneralMethods.class);
        return null;
    }

    SSLContext sc = null;
    sc = SSLContext.getInstance("TLS");
    sc.init(null, new TrustManager[] { new KTPTrustManager() }, new SecureRandom());

    GeneralMethods.writeLog("makeInvalidHTTPSRequest-> " + url + ", " + userName + ", " + userPass, 0, GeneralMethods.class);

    HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
    HttpsURLConnection.setDefaultHostnameVerifier(new KTPHostnameVerifier());
    HttpsURLConnection con = null;
    con = (HttpsURLConnection) new URL(url).openConnection();

    if (userName != null) {
        serverAuth = userName + ":" + userPass;
        serverAuthBase64 = KTPBase64.encode(serverAuth.getBytes());
    }

    try {
        String[] tmpPair = null;
        con.setRequestMethod("POST");

        if (serverAuthBase64 != null)
            con.setRequestProperty("Authorization", "Basic " + serverAuthBase64);

        con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        if (postVars != null) {
            for (int i = 0; i < postVars.length; i++) {
                tmpPair = postVars[i].toString().split("=");

                if (i > 0)
                    urlParameters.append("&" + tmpPair[0] + "=" + URLEncoder.encode(tmpPair[1], "UTF-8"));
                else
                    urlParameters.append(tmpPair[0] + "=" + URLEncoder.encode(tmpPair[1], "UTF-8"));
            }
            con.setRequestProperty("Content-Length", "" + Integer.toString(urlParameters.toString().getBytes().length));
        }

        con.setUseCaches(false);
        con.setDoOutput(true);
        con.setDoInput(true);

        DataOutputStream wr = new DataOutputStream (con.getOutputStream());

        if (postVars != null)
            wr.writeBytes (urlParameters.toString());

        wr.flush();
        wr.close();

        if (con.getResponseCode() == 200) {
            globalRetries = 0;
            rcvdInputStream = con.getInputStream();
        }
        else if (con.getResponseCode() == 401) {
            con.disconnect();
            GeneralMethods.writeLog("error 401", 2, GeneralMethods.class);
            con = null;
            // SEND CONNECTION PROBLEM-INTENT
            return null;
        }
        else {
            GeneralMethods.writeLog("error - connection response code " + con.getResponseCode() + ": " + con.getResponseMessage() + " (length: "+ con.getContentLength() +")\n\n", 1, GeneralMethods.class);
            con.disconnect(); 
            con = null;
            // SEND CONNECTION PROBLEM-INTENT
            return null;
        }

        BufferedReader br = new BufferedReader(new InputStreamReader(rcvdInputStream), 8192 );
        String line;
        while ( ( line = br.readLine() ) != null ) {
                sb.append(line);
        }
        con.disconnect();
        con = null;
    }
    catch(Exception e) {
        handleException(e, 2, GeneralMethods.class);
    }

    GeneralMethods.writeLog("makeInvalidHTTPSRequest: Response is \"" + sb.toString() + "\"\n\n", 0, GeneralMethods.class);

    if(con != null) {
        con.disconnect();
        con = null;
    }
    if (sb.toString().trim() == "")
        return null;
    else
        return sb.toString();
}

Thanks a lot for your help!

Best regards
S.

Answer 1

This might be of help: HttpsURLConnection and intermittent connections