To implement a login / registration system using MySql you need a server-side API, for example in PHP to manipulate the database.
You need something like that on the server side:
// check for tag type
if ($tag == 'login') {
// Request type is check Login
$email = $_POST['email'];
$password = $_POST['password'];
// check for user
$user = $db->getUserByEmailAndPassword($email, $password);
if ($user != false) {
// user found
$response["error"] = FALSE;
$response["uid"] = $user["unique_id"];
$response["user"]["name"] = $user["name"];
$response["user"]["email"] = $user["email"];
$response["user"]["created_at"] = $user["created_at"];
$response["user"]["updated_at"] = $user["updated_at"];
echo json_encode($response);
} else {
// user not found
// echo json with error = 1
$response["error"] = TRUE;
$response["error_msg"] = "Incorrect email or password!";
echo json_encode($response);
}
And the function that queries the database:
public function getUserByEmailAndPassword($username, $password) {
$query = $this->dbh->prepare("SELECT * FROM users2 WHERE username = :username");
$query->bindParam(':username', $username);
$result = $query->execute();
// check for results
if ($query->rowCount() > 0) {
$result = $query->fetch(PDO::FETCH_ASSOC);
$salt = $result['salt'];
$encrypted_password = $result['encrypted_password'];
$hash = $this->checkhashSSHA($salt, $password);
// check for password equality
if ($encrypted_password == $hash) {
// user authentication details are correct
return $result;
}
} else {
// user not found
return false;
}
}
The android 'calls' the php scripts:
private static String login_tag = "login";
public void loginUser(String username, String password) throws ExecutionException, InterruptedException {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("tag", login_tag));
params.add(new BasicNameValuePair("username", username));
params.add(new BasicNameValuePair("password", password));
jsonParser = new DbHandler(activity, this, params).execute();
}
And here is the DbHandler:
public DbHandler1(Activity activity, MyCallback dbIntf, List<NameValuePair> params) {
this.activity = activity;
intf = dbIntf;
this.params = params;
}
public JSONObject makeHttpRequest() {
// Making HTTP request
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(MainActivity.baseUrl);
//If database contains greek characters instantiate with UTF-8 Encoding
httpPost.setEntity(new UrlEncodedFormEntity(params, "UTF-8"));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (HttpHostConnectException e) {
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
Toast.makeText(activity, R.string.connection_error, Toast.LENGTH_LONG).show();
}
});
} catch (IOException e) {
e.printStackTrace();
}
try {
//If database contains greek characters instantiate with UTF-8 Encoding
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "UTF-8"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
@Override
protected JSONObject doInBackground(Void... params) {
jObj = makeHttpRequest();
return jObj;
}
@Override
protected void onPostExecute(JSONObject jsonObject) {
super.onPostExecute(jsonObject);
try {
intf.onRemoteCallComplete(jsonObject);
} catch (JSONException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
So the php scripts 'catches' the tag and if the user exists it returns a JSON response to the device. For example:
{
"tag": "login",
"success": 1,
"error": 0,
}
The data transfered from the MySql server must be JSON encoded.
On the android device you must read the JSON Response and act accordingly.
Take a look here for more details.
