Login/Register Script

brdnwi

I'm trying to develope a script to let people register usernames. Right now, I have one user in my database and I'm trying to test this script with it. Basically, I want to enter that username into the form and when it's submitted, I want it to check the database, and then I want it to return a "username already in use" error. I'd appreciate a code check. Here is all the code. Feel free to cut and paste and test it. Right now the form submits and reloads itself.

<?
session_start();

$connect = mysql_connect("localhost", "root", "pass")
	or die(mysql_error());

mysql_select_db("world");

function UserTaken($username) {
  $query = "SELECT username FROM users WHERE username = '$username'";
  $send = mysql_query($query)
  				or die(mysql_error());

  $results = mysql_fetch_array($send);
}

 if(UserTaken($_POST['user'])){
      $username = $_POST['user'];
      die("Sorry, the username: <strong>$username</strong> is already taken, please pick another one.");
   }

?>

<html>

<head>
<title>PHP Login</title>
</head>

<body>



<form action="<? echo $_SESSION['PHP_SELF']; ?>" method="post">
<table>

<tr>
<td>Username: </td>
<td><input type="text" name="user" maxlength="20" length="20" value=""></td>
</tr>
<tr>
<td>Password: </td>
<td><input type="password" name="pass" maxlength="20" length="20" value=""></td>
</tr>
<tr>
<td><input type="submit" value="Join" name="submit">
</tr>
</table>
</form>

</body>
</html>

niroshan

Hi brdnwi,

I went through your code and i found some mistakes so thought of sharing them with you 🙂

You are not checking whether user clicked the submit button. This is a mistake because according to your code the checking of the user name will happen without pressing the submit button even.
Your IF condition is never goner execute because your "UserTaken" function not returning anything.

TIP:
Dont use "mysql_error()" to display the error messages because its much easier for hackers to hack your system so instead use your own error message.

I have did some changes to your code, here is the code. Hope this helps you.

<?php
if(isset($_POST['submit']))
{
	session_start();
	$connect = mysql_connect("localhost", "root", "triadpass") or die("Error connecting to the database");	
	mysql_select_db("test") or die ("error selecting db");

function UserTaken($username)
{
  $query = "SELECT username FROM users WHERE username = '$username'";
  $send = mysql_query($query) or die("Error in the query");

  if(mysql_num_rows($send)==0)
  {
	  return false;
  }
  else
  {
	  return true;
  }						  
}


if(UserTaken($_POST['user']))
{
  $username = $_POST['user'];
  die("Sorry, the username: <strong>$username</strong> is already taken, please pick another one.");
}
}
?>

<html>

<head>
<title>PHP Login</title>
</head>

<body>



<form action="<? echo $_SESSION['PHP_SELF']; ?>" method="post">
<table>

<tr>
<td>Username: </td>
<td><input type="text" name="user" maxlength="20" length="20" value=""></td>
</tr>
<tr>
<td>Password: </td>
<td><input type="password" name="pass" maxlength="20" length="20" value=""></td>
</tr>
<tr>
<td><input type="submit" value="Join" name="submit">
</tr>
</table>
</form>

</body>
</html>

Regards,
Niroshan

brdnwi

thank you. PHP is my first application language. I've been in it for two weeks. I like it, and I'll take what you said and use it as I learn.

I see it now works. However, what exactly is happening with the 'return' line? What is return false doing and return true? So if there are no rows in the table, it returns false? I'm just confused about how that sends the information.

-Brandon

brdnwi

I think I got it. If the number of rows is 1, then the answer is true, which means the username is already taken. This 'true' is sent to the next if statement which calls the function. Since the answer is true, it executes the statements.

Wow, this stuff makes my brain tired, but I enjoy it. Thanks again.

niroshan

Yeah exactly 😃

Well first of all good luck for you.If you need any help please feel free to ask but remember do it your self first before asking ok 🙂

well return is nothing fancy.. It uses to pass values. In this case it return true and false. But if you want you can pass a variable as well for example:

function test()
{
$a=1;
$b=2;
$c=$a+$b;

 return  $c;

}

so when you call the function you can assign it to a variable and use that variable for what ever you want. ex:

$return_value=test();

so now $return_value will have the value of $c.

So in your case you are calling the "UserTaken" function in a IF condition. so as you know if we have true in a If condition that means it goes in side the If condition. So its easy, if there are records in the database I return true so it goes in to the IF condition and print the error. 😃

Hope this is clear enough for you.

Good luck,

Regards,
Niroshan

brdnwi

niroshan wrote:
Yeah exactly 😃

Well first of all good luck for you.If you need any help please feel free to ask but remember do it your self first before asking ok 🙂

Definetly. This forum was my last resort. I had been working on the application for two hours trying different things with no luck.I'm a web designer by nature, but now I've decided I want to get into this 'back end' stuff. I know it's going to take a lot of learning on my part and reading through php.net like crazy, but I'll get it.

-Brandon