Check if username already exists?

doomdude · September 25, 2011

I'm working with a registration/login system from a tutorial. It's got email validation to make sure it does not exist but I'm struggling to add the same to the username field:

Working code:

<?php

include ('database_connection.php');
if (isset($_POST['formsubmitted'])) {
    $error = array();//Declare An Array to store any error message  
    if (empty($_POST['name'])) {//if no name has been supplied 
        $error[] = 'Please Enter a name ';//add to array "error"
    } else {
        $name = $_POST['name'];//else assign it a variable
    }

    if (empty($_POST['e-mail'])) {
        $error[] = 'Please Enter your Email ';
    } else {


        if (preg_match("/^([a-zA-Z0-9])+([a-zA-Z0-9\._-])*@([a-zA-Z0-9_-])+([a-zA-Z0-9\._-]+)+$/", $_POST['e-mail'])) {
           //regular expression for email validation
            $Email = $_POST['e-mail'];
        } else {
             $error[] = 'Your EMail Address is invalid  ';
        }


    }


    if (empty($_POST['Password'])) {
        $error[] = 'Please Enter Your Password ';
    } else {
        $Password = $_POST['Password'];
    }


    if (empty($error)) //send to Database if there's no error '

    { // If everything's OK...

        // Make sure the email address is available:
        $query_verify_email = "SELECT * FROM members  WHERE Email ='$Email'";
        $result_verify_email = mysqli_query($dbc, $query_verify_email);
        if (!$result_verify_email) {//if the Query Failed ,similar to if($result_verify_email==false)
            echo ' Database Error Occured ';
        }
    if (mysqli_num_rows($result_verify_email) == 0) { // IF no previous user is using this email .


            // Create a unique  activation code:
            $activation = md5(uniqid(rand(), true));


            $query_insert_user = "INSERT INTO `members` ( `Username`, `Email`, `Password`, `Activation`) VALUES ( '$name', '$Email', '$Password', '$activation')";


            $result_insert_user = mysqli_query($dbc, $query_insert_user);
            if (!$result_insert_user) {
                echo 'Query Failed ';
            }

            if (mysqli_affected_rows($dbc) == 1) { //If the Insert Query was successfull.


                // Send the email:
                $message = " To activate your account, please click on this link:\n\n";
                $message .= WEBSITE_URL . '/activate.php?email=' . urlencode($Email) . "&key=$activation";
                mail($Email, 'Registration Confirmation', $message, 'From: [email protected]');

                // Flush the buffered output.


                // Finish the page:
                echo '<div class="success">Thank you for
registering! A confirmation email
has been sent to '.$Email.' Please click on the Activation Link to Activate your account </div>';


            } else { // If it did not run OK.
                echo '<div class="errormsgbox">You could not be registered due to a system
error. We apologize for any
inconvenience.</div>';
            }

        } else { // The email address is not available.
            echo '<div class="errormsgbox" >That email
address has already been registered.
</div>';
        }

    } else {//If the "error" array contains error msg , display them
        
        

echo '<div class="errormsgbox"> <ol>';
        foreach ($error as $key => $values) {
            
            echo '	<li>'.$values.'</li>';


       
        }
        echo '</ol></div>';

    }
  
    mysqli_close($dbc);//Close the DB Connection

} // End of the main Submit conditional.



?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Game Name - Home</title>
<link rel="stylesheet" type="text/css" href="style.css" />
</head>
<body>

<div id="container">
<div id="header">
<?php include("includes/header.php"); ?>
</div>
<div id="nav">
<?php include("includes/nav.php"); ?>

</div>
<div id="content">
<form action="index.php" method="post" class="registration_form">
  <fieldset>
    <legend>Registration Form</legend>

    <p>Create A new Account<br />Already a member? <a href="login.php">Log in</a></p>
    
    <div class="elements">
      <label for="name">Username:</label>
      <input type="text" id="name" name="name" size="25" />
    </div>
    <div class="elements">
      <label for="e-mail">E-mail:</label>
      <input type="text" id="e-mail" name="e-mail" size="25" />
    </div>
    <div class="elements">
      <label for="Password">Password:</label>
      <input type="password" id="Password" name="Password" size="25" />
    </div>
    <div class="submit">
     <input type="hidden" name="formsubmitted" value="TRUE" />
      <input type="submit" value="Register" />
    </div>
  </fieldset>
</form>
</div>
<div id="footer">
<?php include("includes/footer.php"); ?>
</div>
</div>
</body>
</html>

I've tried adding this after the email verification:

// Make sure the user is available:
        $query_verify_user = "SELECT * FROM members  WHERE Username ='$name'";
        $result_verify_user = mysqli_query($dbc, $query_verify_user);
        if (!$result_verify_user) {
            echo ' Database Error Occured ';
        }
}
    if (mysqli_num_rows($result_verify_user) == 0) { // IF no previous user is using this user .

But that just returns me with:

It works to stop username/email duplication but now returns:

Query Failed You could not be registered due to a system error. We apologize for any inconvenience.

Not sure where I'm going wrong tbh.

Nethox · September 25, 2011

Can you post the new code? I'm not sure where exactly you've inserted your user verification script.

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Check if username already exists?

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