android - cannot send data to database of web server

Question

When I directly go to the link of PHP by browser, it creates an empty record in the database. However, when I send data using app, it fails.

Java:

protected String doInBackground(String... params) {
    String reg_url = "http://www.minigameserver.square7.ch/register.php";
    String user_name = params[0];
    String user_ac = params[1];
    String user_pw = params[2];
    try {
        URL url = new URL(reg_url);
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setRequestMethod("POST");

        httpURLConnection.setDoOutput(true);
        OutputStream OS = httpURLConnection.getOutputStream();
        BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS,"UTF-8"));
        String data = URLEncoder.encode("user_name","UTF-8")+"="+URLEncoder.encode(user_name,"UTF-8")+"&"+
                URLEncoder.encode("user_ac","UTF-8")+"="+URLEncoder.encode(user_ac,"UTF-8")+"&"+
                URLEncoder.encode("user_pw","UTF-8")+"="+URLEncoder.encode(user_pw,"UTF-8");
        bufferedWriter.write(data);
        bufferedWriter.flush();
        bufferedWriter.close();
        OS.close();

        httpURLConnection.disconnect();

        return "done!";
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return "fail!";
}

When I run the app, the massage "done!" is shown.

So, there are no Exception happening. But, why there are no new record?

I saw someone have tired to register with username of teset. Is he mind to tell who did so that I can trace the post.

When I try the code provided by Arshak. The following error comes out. E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f7d9eaad530

register.php:

<?php
require "db_connect.php";

$user_name = $_POST["user_name"];
$user_ac = $_POST["user_ac"];
$user_pw = $_POST["user_pw"];
$user_pw_enc = md5($user_pw);

$sql = "INSERT INTO user(user_name, user_ac, user_pw) VALUES ('$user_name', '$user_ac', '$user_pw_enc')";

$sql2 = "SELECT * FROM user WHERE user_name = '$user_name'";
$result2 = $conn->query($sql2);

$sql3 = "SELECT * FROM user WHERE user_ac = '$user_ac'";
$result3 = $conn->query($sql3);

if($result2->num_rows == 0 && $result3->num_rows == 0){
if ($conn->query($sql) === TRUE)
        echo "Your account is created successfully!\nYou can login now!";
else
    echo "Error: " . $sql . "<br>" . $conn->error;
}
else {
if($result2->num_rows > 0)  
    echo "The user name is used!<br>";
if($result3->num_rows > 0)
    echo "The user account is used!<br>";
}

?>

you might be doing some mistakes on your client side try to check error_log on server side — eLemEnt
– eLemEnt, Commented Jul 28, 2016 at 11:20
What is the response string that you get? Please always provide complete information. — Sufian
– Sufian, Commented Jul 28, 2016 at 14:06
@U.Swap, you mean backgroundTask.execute(user_name_s,user_ac_s,user_pw_s);? — Keroro Chan
– Keroro Chan, Commented Jul 28, 2016 at 14:50
@KeroroChan please use @ before username if you want to notify the user about the comment. — Sufian
– Sufian, Commented Jul 28, 2016 at 14:51

Arshak · Accepted Answer · 2016-07-29 04:30:42Z

1

I have updated your code, see if data gets inserted:

protected String doInBackground(String... params) {
String reg_url = "http://www.minigameserver.square7.ch/register.php";
String user_name = params[0];
String user_ac = params[1];
String user_pw = params[2];
try {
        URL url = new URL(reg_url);
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
        httpURLConnection.setRequestMethod("POST");
        httpURLConnection.setDoOutput(true);
        httpURLConnection.setDoInput(true);
        httpURLConnection.connect();
        DataOutputStream OS = new DataOutputStream(httpURLConnection.getOutputStream());
        String data = URLEncoder.encode("user_name","UTF-8")+"="+URLEncoder.encode(user_name,"UTF-8")+"&"+
                URLEncoder.encode("user_ac","UTF-8")+"="+URLEncoder.encode(user_ac,"UTF-8")+"&"+
                URLEncoder.encode("user_pw","UTF-8")+"="+ URLEncoder.encode(user_pw,"UTF-8");
        OS .writeBytes(data);
        OS .flush();
        OS.close();

        int responseCode=httpURLConnection.getResponseCode();
        String messageFromServer;
        if (responseCode==200) {
            messageFromServer=fromInputStream(httpURLConnection.getInputStream());
            Log.v("RegistrationMessage ",messageFromServer);
            httpURLConnection.disconnect();
            return messageFromServer;
        }

        httpURLConnection.disconnect();

    } catch (IOException e) {
        e.printStackTrace();
    }
    return "fail!";
}

//Add this method inside your AsyncTask
public String fromInputStream(InputStream stream) throws IOException {
        InputStreamReader streamReader = new
                InputStreamReader(stream);
        BufferedReader bufferedReader = new BufferedReader(streamReader);
        StringBuilder builder = new StringBuilder();
        String tempString = "";
        while ((tempString = bufferedReader.readLine()) != null) {
            builder.append(tempString);
        }
        return builder.toString();
    }

edited Jul 29, 2016 at 4:30

answered Jul 28, 2016 at 11:38

Arshak

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27 Comments

Keroro Chan Over a year ago

You input the name of teset to test it?

Sufian Over a year ago

@KeroroChan I think this should be the correct answer as you aren't calling httpURLConnection.connect() anywhere. It means that the server is not even called!!!

Sufian Over a year ago

@KeroroChan please see this question - stackoverflow.com/questions/33719149/… I think you should switch to non-Marshmallow device and test again. But calling httpURLConnection.connect() is a must, otherwise you're only trying to fool yourself.

Arshak Over a year ago

@KeroroChan I forgot to add fromInputStream() method in the above code. I have updated it, check again. Now it will also display message shown in your php file, such as Your account is created successfully!\nYou can login now! , etc. I guess the data got send because, it might be some build issue that you were facing earlier. I'm happy my code helped you, now you can upvote & mark my answer as correct answer.

Arshak Over a year ago

@KeroroChan Correct & For now you are receiving less amount of data, so it is fine to use string for now. But when you are receiving a lot of data then i'd recommend using StringBuilder instead of String.

|

Miguel González · Accepted Answer · 2016-07-28 11:36:05Z

@Override
protected String doInBackground(String... params) {
    // Create a new HttpClient and Post Header
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://www.minigameserver.square7.ch/register.php");

    try {
       //add data
       List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(1);
       nameValuePairs.add(new BasicNameValuePair("user_name", params[0]));
       nameValuePairs.add(new BasicNameValuePair("user_ac", params[1]));
       nameValuePairs.add(new BasicNameValuePair("user_pw", params[2]));
       httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
       //execute http post
       HttpResponse response = httpclient.execute(httppost);

    } catch (ClientProtocolException e) {

    } catch (IOException e) {

    }
}

You can use Volley Android Networking Library to post your data. Official document is https://developer.android.com/training/volley/simple.html.

Sufian · Accepted Answer · 2016-07-28 14:35:00Z

0

I tried to test the URL and yes, it was working. Since there are already posts that show some fixes on your codes, I'm just gonna give you a tip.

First is, since you're not sure of what could be the possible exception you'll get. Try to make it general. remove one catch() statement and instead, use:

catch(Exception e){
    e.printStackTrace();
}

In that way, all exceptions will be caught and you'll easily find what's causing issues on your code.

Next is, since you are communicating with a server, so it's gonna be a request-respond procedure. Actually, you're doing the right thing since after sending some requests, I'm able to receive a respond. But to make it efficient, your server should also respond something like a boolean indicator. Let's say it will respond 1 if it has successfully registered and 0 if not. Then your mobile application will handle the result.

Also, most likely you won't be able to get that fail message since it's outside the try-catch.

edited Jul 28, 2016 at 14:35

Sufian

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answered Jul 28, 2016 at 11:52

fmpsagara

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2 Comments

Keroro Chan Over a year ago

I have the message for success and failure of registration. And, when I use inputstream, error comes out.

Keroro Chan Over a year ago

The error E/Surface: getSlotFromBufferLocked: unknown buffer: 0x7f55ab21fff0 comes out.

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