app.get('/', function(req, res){ //response to http server GET request at home url
// when using this form to upload, no problems are experienced
    console.log('GET request at /');
    res.writeHead(200, {'Content-Type': 'text/html'});
        res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
        res.write('<input type="file" name="filetoupload"><br>');
        res.write('<input type="submit">');
        res.write('</form>');
        return res.end();
});

app.post('/fileupload', function(req, res){ //response to http server POST request at home url
    console.log("POST request received at /fileupload");
    res.writeHead(200, {'Content-Type' : 'text/html'});
    var form = formidable.IncomingForm();
    form.uploadDir = __dirname + "/temp"
    form.keepExtensions = true;

    form.parse(req, function(err, fields, files){
        console.log("Parsing...");
        if (err) {throw err};
    });

    form.on('file', function(name, file){ // the 'file' event is never emitted when receiving an upload from android...
        console.log("Uploaded: " + file.name);
    });

    form.on('end' , function(){
        console.log("Ending...");
        res.json();
        res.end();
    });

    form.on('progress', function(bytesReceived, bytesExpected){
        console.log((bytesReceived/bytesExpected) * 100 + " %");
    })

    form.on('error', function(err){
        console.log("There has been an error.");
        console.log(err);
    })

});

protected Boolean doInBackground(String... strings){
    //this asynchronously uploads a file that the user has selected
    // it returns true or false based on whether or not the upload was successful

    for (String string: strings) { // strings is an array of strings that represents the paths of the files the user selected
        try{
            URL url = new URL(urlString); //urlString is a string that hold's the URL of the server I am hosting at 'fileupload'
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();

            connection.setConnectTimeout(4000);


            //POST request header
            connection.setRequestMethod("POST");
            connection.setRequestProperty("USER-AGENT", "Mozilla/5.0");
            connection.setRequestProperty("Accept-Language", "en-US, en;q=0.5");

            connection.setDoOutput(true);
            DataOutputStream os = new DataOutputStream(connection.getOutputStream());
            BufferedReader outputReader = new BufferedReader(new FileReader(string));

            String outputLine;

            while ((outputLine = outputReader.readLine()) != null) {
                os.write(outputLine.getBytes());
            }

            os.flush();
            os.close();

            int responseCode = connection.getResponseCode();
            Log.i(TAG, "Response code: " + responseCode);

            if (responseCode != HttpURLConnection.HTTP_OK) {
                return false;
            }

            BufferedReader in = new BufferedReader(new InputStreamReader
                    (connection.getInputStream()));

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

            Log.i(TAG, response.toString());

            connection.disconnect();

        } catch (IOException e) {
            Log.e(TAG, e.toString());
            return false;
        }
    }
    return true;
}