Creating database-driven user homepage based on register in php

Question

I've got a predicament that I'd love your help with if you have any insight. In Short, I'm currently doing a study portal type project and I'm looking to have it fully database driven so that when I register for a module, that particular module appears on the user's profile because as of right now, it doesn't matter if tom, dick or harry logs in, they all see the same three modules for a particular course.

So upon registering, a user would choose a course, a list of relevant modules would appear and then a user would choose their modules. From that, their homepage would be populated by the html & CSS code attached to that module.

There's 3 tables that interact with this section. UserDemo, course and module.

Here is the code I have to do with registering as a user currently (the course & modules must be added):

accounts\signup.php

<?php 
    include '../inc/db.php';
    include '../inc/functions.php';


    if (isset($_POST['signup'])) {
        $fName = p_s($_POST['fName']);
        $lName = p_s($_POST['lName']);
        $email = p_s($_POST['email']);
        $password = p_s($_POST['password']);
        $rpassword = p_s($_POST['rpassword']);
        $contentID = p_s($_POST['contentID']);
        if (!empty($fName) && !empty($lName) && !empty($email) && !empty($password) && !empty($contentID)) {
            if (strlen($password) === strlen($rpassword)) {

          $options = [
              'cost' => 12,
          ];
          $password = password_hash($password, PASSWORD_BCRYPT, $options);
          $created_at = date('Y-m-d G:i:s');

                $sql = "INSERT INTO usersDemo (fName, lName, email, password, contentID, status, created_at) VALUES ('$fName','$lName', '$email', '$password', '$contentID', 'approved', '$created_at')";
                if (mysqli_query($conn, $sql)) {
                    header('Location: ../signup.php?suc');exit();
                }
            }else{
                header('Location: ../signup.php?fidpass');exit();
            }
        }else{
            header('Location: ../signup.php?fempt');exit();
        }


    }

inc\signup.php

    <form action="accounts/signup.php" method="POST">

       <div id="fade-box">
         <h2>Register</h2>
      <div class="form-group">
        <input name="fName" type="text" class="form-control" id="fName" placeholder="Enter your first name" required>
      </div>
      <div class="form-group">
        <input name="lName" type="text" class="form-control" id="lName" placeholder="Enter your last name" required>
      </div>
      <div class="form-group">
        <input name="email" type="email" class="form-control" id="email" placeholder="Email" required>
      </div>
      <div class="form-group">
        <input name="password" type="password" class="form-control" id="password" placeholder="Password" required>
      </div>
      <div class="form-group">
        <input name="rpassword" type="password" class="form-control" id="rpassword" placeholder="Repeat Password" required>
      </div>
      <div class="form-group">
        <input name="contentID" type="text" class="form-control" id="contentID" placeholder="Enter your contentID" required>
      </div>
      <button name="signup" type="submit" class="btn btn-success">Register</button>
      </div>
    </form>

This is my current plan of attack:

Plan of attack:

1. Select module name, module description from db

2. Display on screen

3. Iterate through values and display

4. Copy code for UI into for loop

What would your opinions be on this plan of attack or does anyone know of an alternative (and maybe easier) way of accomplishing this.

Thanks in advance for your time and help :)

Answer 1

Use prepared statements, you are vulnerable to sql injections and prepared statement will prevent that.

<?php 
    include '../inc/db.php';
    include '../inc/functions.php';


    if (isset($_POST['signup'])) {
        $fName = p_s($_POST['fName']);
        $lName = p_s($_POST['lName']);
        $email = p_s($_POST['email']);
        $password = p_s($_POST['password']);
        $rpassword = p_s($_POST['rpassword']);
        $contentID = p_s($_POST['contentID']);
        if (!empty($fName) && !empty($lName) && !empty($email) && !empty($password) && !empty($contentID)) {
            if (strlen($password) === strlen($rpassword)) {

          $options = [
              'cost' => 12,
          ];
          $password = password_hash($password, PASSWORD_BCRYPT, $options);
          $created_at = date('Y-m-d G:i:s');

        $sql = "INSERT INTO usersDemo (fName, lName, email, password, contentID, status, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)"; 

    if($stmt = $conn->prepare($sql)){

       $stmt->bind_param('ssssiis',$fName,$lName,$email,$password,$contentID,'approved',$created_at); //s = string i = int

       /* execute query */
       $stmt->execute();
    }
       /* free results */
       $stmt->free_result();

    $stmt->close();
    
                if (mysqli_query($conn, $sql)) {
                    header('Location: ../signup.php?suc');exit();
                }
            }else{
                header('Location: ../signup.php?fidpass');exit();
            }
        }else{
            header('Location: ../signup.php?fempt');exit();
        }


    }