Are you using purely MySQL? I have made a signup and login page before as part of a web app and used Php to do this. I believe you can use Php for apks so I will write in Php, but you should be able to translate to your language with ease.
<?php
if (isset($_POST['signup-submit'])) { //this is so that the following can only be done on
the button press (name of it is signup-submit)
require 'dbh.inc.php';
$username = $_POST['Username'];
$email = $_POST['mail'];
$password = $_POST['pwd'];
$confirmpassword = $_POST['cpwd']; //this is all off the details of the user passed
through to be run through this script into the
database
if (empty($username) || empty($email) || empty($password) || empty($confirmpassword)) {
header("Location: ../index.php?error=emptyfields&uid=". $username. "&mail=". $email);
exit();
} //checking for empty fields
else if (!filter_var($email, FILTER_VALIDATE_EMAIL) && !preg_match("/^[a-zA-Z0-9 ]*$/", $username)) {
header("Location: ../index.php?error=invalidemail&uid");
exit();
}
else if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
header("Location: ../index.php?error=invalidemailuid");
exit();
}
else if (!preg_match("/^[a-zA-Z0-9 ]*$/", $username)) {
header("Location: ../index.php?error=invaliduid&email=". $email);
exit();
}
else if ($password !== $confirmpassword) {
header("Location: ../index.php?error=checkpasswords&mail=".$email. "&uid=".$username);
exit();
} //checking all characters used are only that which you allow
else {
$sql = "SELECT uidusers FROM users WHERE uidusers=?";
$sqly = "SELECT emailusers FROM users WHERE emailusers=?";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)) {
header("Location: ../index.php?error=sqlerror");
exit();
} //using prepared statements to insert user info
else {
mysqli_stmt_bind_param($stmt, "s", $username);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
$resultCheck = mysqli_stmt_num_rows($stmt);
if ($resultCheck > 0) {
header("Location: ../index.php?error=usertaken&mail=". $email);
exit();
} //checking for existing details
if (!mysqli_stmt_prepare($stmt, $sqlx)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
if (!mysqli_stmt_prepare($stmt, $sqly)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
else {
mysqli_stmt_bind_param($stmt, "s", $email);
mysqli_stmt_execute($stmt);
mysqli_stmt_store_result($stmt);
$resultCheck3 = mysqli_stmt_num_rows($stmt);
if ($resultCheck3 > 0) {
header("Location: ../index.php?error=emailtaken");
exit();
} //storing details
else {
$sql = "INSERT INTO users (uidusers, emailusers,
pwdusers, invcode) VALUES (?, ?, ?, ?) ";
$stmt = mysqli_stmt_init($conn);
if (!mysqli_stmt_prepare($stmt, $sql)) {
header("Location: ../index.php?error=sqlerror");
exit();
}
else {
$hashedpwd = password_hash($password, PASSWORD_DEFAULT); //hashing passwords
mysqli_stmt_bind_param($stmt, "sss", $username, $email, $hashedpwd);
mysqli_stmt_execute($stmt);
header("Location: ../index.php?signup=success"); //all details stored successfully
As for your access token, I would suggest adding a function to run a uniqid() function along with another function to check for existing tokens so that duplicates aren't made ( I did this for another similar reason to yours) and then using similar code as above to write that in.
I'm not sure what your shop ID is for but I have options for 2 eventualities:
If it's just a sort of ID, auto increment it in the database
If it's to show which shop the person entered, use foreign keys to link the column to a parent table with all the shops listed and set the relationship to cascade. Then make a button to switch shops that will
A) send an update to the database, overwriting the child column and row of the user
B) redirect the user to the new shop
(I have no idea why the second half of the code is green, but if you remove my comments you should be good, though I'd advise you to write your own code so that you can see how it works and adapt it to your own project)
