auth.php

<?php

//use pdo or mysqli
	ob_start();
	session_start();
	if( isset($_SESSION['user'])){
		header("Location: home.php");
	}
	include_once 'connect.php';
	include_once 'functions.php';


	$error = false;

	if ( isset($_POST['btn-login']) ) {
		
		// clean user inputs to prevent sql injections
		$name = trim($_POST['name']);
		$name = strip_tags($name);
		$name = htmlspecialchars($name);
		
		$email = trim($_POST['email']);
		$email = strip_tags($email);
		$email = htmlspecialchars($email);
		
		$pass = trim($_POST['pass']);
		$pass = strip_tags($pass);
		$pass = htmlspecialchars($pass);
		
		// basic name validation
		if (empty($name)) {
			$error = true;
			$nameError = "Please enter your full name.";
		} else if (strlen($name) < 3) {
			$error = true;
			$nameError = "Name must have atleat 3 characters.";
		} else if (!preg_match("/^[a-zA-Z ]+$/",$name)) {
			$error = true;
			$nameError = "Name must contain alphabets and space.";
		}
		
		//basic email validation
		if ( !filter_var($email,FILTER_VALIDATE_EMAIL) ) {
			$error = true;
			$emailError = "Please enter valid email address.";
		} else {
			// check email exist or not
			$query = "SELECT userEmail FROM users WHERE userEmail='$email'";
			$result = mysql_query($query);
			$count = mysql_num_rows($result);
			if($count!=0){
				$error = true;
				$emailError = "Provided Email is already in use.";
			}
		}
		// password validation
		if (empty($pass)){
			$error = true;
			$passError = "Please enter password.";
		} else if(strlen($pass) < 6) {
			$error = true;
			$passError = "Password must have atleast 6 characters.";
		}
		
		// password encrypt using SHA256();
		$password = hash('sha256', $pass);
		
		// if there's no error, continue to signup
		if( !$error ) {
			
			$query = "INSERT INTO users(userName,userEmail,userPass) VALUES('$name','$email','$password')";
			$res = mysql_query($query);
				
			if ($res) {
				$errMSG = "Successfully registered, you may login now";

				sender('sgnUpIns',$errMSG);
				Location('login');
				unset($name);
				unset($email);
				unset($pass);
			} else {
				$errMSG = "Something went wrong, try again later...";
				sender('sgnUpIns',$errMSG,"error");
				Location('signup');
			}	
				
		}
	}
?>