I have created a class 'validate' to validate two fields i.e 'firstname' and 'lastname'. It is not working fine, it is showing error when field is empty but when I submit the form with non-empty fields the error is still there. How to execute this on form submission?
<?php
class validation {
public $firstName, $lastName, $errorFirstName = '', $errorLastName = '';
function __constructor($fName, $lName){
$this->firstName = $fName;
$this->lastName = $lName;
}
function check(){
if($_SERVER["REQUEST_METHOD"] == "POST"){
if(empty($this->firstName)){
$this->errorFirstName = 'First name is required';
} else {
$this->errorFirstName = 'Input is okay';
}
if(empty($this->lastName)){
$this->errorLastName = 'Last name is required';
} else {
$this->errorLastName = 'Input is okay';
}
}
}
}
$obj = new validation($_POST['firstname'], $_POST['lastname']);
$obj->check();
$errorF = $obj->errorFirstName;
$errorL = $obj->errorLastName;
?>
<!DOCTYPE html>
<html lang = "en-US" dir = "ltr">
<head>
<title>Home</title>
<meta charset = "UTF-8"/>
</head>
<body>
<form method = "POST" action="<?php echo $_SERVER["PHP_SELF"]?>">
<label>First Name: </label>
<input type = "text" name = "firstname" placeholder = "John"/>
<p class = "error"><?php echo $errorF;?></p>
<label>Last Name: </label>
<input type = "text" name = "lastname" placeholder = "Doe"/>
<p class = "error"><?php echo $errorL;?></p>
<input type="submit">
</form>
</body>
</html>
Everyone always makes "database class" and "validation class". Ehh .... whaaaaay?
Don't make a validation class. It never works. The most .. emm ... sustainable options for validating user input are:
With using entities for validation, it is quite simple. In your case you would have class Profile where you have method setFirstName(string $name). Then within this method you do the validation and on error throw a custom made exception, like InvalidFirstName .. or something like that.
Using value objects is a bit trickier, but it prevents the code duplication. For example, you need to validate email address. So, the way you would want to use it would look something like:
try {
$profile = new Profile;
$profile->setEmail(new EmailAddress($_POST['email']));
} catch (InvalidArgumentException $e){
// validation failed
}
Therefore, to get this behavior, you would have the class defined kinda like this:
class EmailAddress
{
private $email;
public function __construct(int $emailId = null, string $email = null)
{
if (!$this->isValid($email)) {
throw new InvalidArgumentException('Not valid email address');
}
$this->email = $email;
}
private function isValid($email)
{
return filter_var($email, FILTER_VALIDATE_EMAIL) !== false;
}
public function __toString()
{
return $this->email;
}
}
This approach is a lot more expressive, but it tends to become a big gnarly, when interacting with persistence layer.
In practice, the best option is to use combination of these both solutions: