functions.php

<?php // <--- do NOT put anything before this PHP tag

// in PHP we can create our own functions to do whatever we need.
// the benefit of using a function is that we can reduce duplicate code.

// here is a function that will connect the Database
// wherever we need to connect to the database we just call this function.
function connectToDatabase()
{
	// connect to our SQLITE database 
	//$dbh = new PDO("sqlite:./database/OnlineShop.db");
	
	// if you had a MYSQL server you could use this instead:
	$dbh = new PDO("mysql:host=localhost;dbname=onlineshop.db", "root", "admin");
	
	// enable errors
	$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
	
	//Turn OFF emulated prepared statements.
	$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
	
	// return the database handle.
	return $dbh;
}

function showErrorMessage($cookieMessage)
{
	echo "<h4 class = 'errormsg'>Error: $cookieMessage </h4>";
}

// run this function on untrusted data before we echo it on the page.
function makeOutputSafe($unsafeString)
{
	$safeOutput = htmlspecialchars($unsafeString, ENT_QUOTES,"UTF-8");
	return $safeOutput;
}	

// this function lets you redirect the user to a different web page.
function redirect($newURL)
{
	// the header location function will send a user to the specified URL.
	// please note that this function MUST be called before any HTML is displayed on the page or it wont work.
	header("Location: $newURL");
	
	// we just redirected the user, that means there is no one around to view this page.
	// so we can just stop processing this page.
	die();
}

// please note that this function MUST be called before any HTML is displayed on the page or it wont work.
function setCookieMessage($cookieMessage)
{
	setcookie("CookieMessage", $cookieMessage);
}

// please note that this function MUST be called before any HTML is displayed on the page or it wont work.
function getCookieMessage()
{
	if(isset($_COOKIE['CookieMessage']))
	{
		$message = $_COOKIE['CookieMessage'];
		deleteCookie("CookieMessage");
		return makeOutputSafe($message);
	}
	else return "";	
}	

// please note that this function MUST be called before any HTML is displayed on the page or it wont work.
function deleteCookie($cookieName)
{
	// to delete a cookie, you set the expiry date to a date in the past.
	// in this case set the expiry date to 1 second past midnight 1st of Jan 1970
	setcookie($cookieName,"",1);
}

// this function will return true if $needle is found inside $haystack.
function stringContains($haystack, $needle)
{
	return strpos($haystack, $needle) !== false;
}



// I strongly suggest you do not close the PHP tag in this file.
// it can cause issues with setcookie() and header()