PHP Scripts 1- Basic Validator

Form validation is an essential part of web programming, whatever server side scripting we are using. Client side validation can be done with the help of Javascript.
But the server side validation is also required, if the client browser disabled its Javascript Features.

Here , you can find a sample code written in PHP for form validation.
Beginners can modify the code or learn the underlying principle of the validator script.

F

/*
* Class Validator()
* general Purpose validation Script for PHP Validation on Elements
* Use the validator constructor for setting values which needs the validation
* Invoke validate method for vaidation test
*/

class Validator
{
private $validateFields;
public $errorMessage;

/*
* Constructor
* Param $args - Validation elements and rules
*/

function __construct($args)
{
$this->validateFields = $args;
}

/*
* Validationn for Email
* Param $string - String
*/

function validateEmail($string)
{
$pattern = "/([a-zA-Z0-9._\&\*-]*)@([a-zA-Z0-9._-]*).([a-zA-Z0-9]{2,})/";
if(preg_match($pattern,$string)){
return true;
}else{
return false;
}
}

/*
* Validation for URL
* Param $string - String
*/

function validateUrl($string)
{
$pattern = "/(http|https):\/\/([a-zA-Z0-9_.-]*).([a-zA-z0-9]{2,})/";
if(preg_match($pattern,$string)){
return true;
}else{
return false;
}
}

/*
* Validate For Null
* Param String
*/

function validateNull($string)
{
if(is_null($string)){
return true;
}else{
return false;
}
}
/*
* Validate for numeric
*/
function validateNumeric($string)
{
if(is_numeric($string)){
return true;
}else{
return false;
}
}

/*
* Validte for Empty
* Param $string - String
*/

function validateEmpty($string)
{
$string = trim($string);
if($string =="" || is_null($string)){
return true;
}else{
return false;
}
}
/*
* Validate for special chars
*/
function validateSpecial($string)
{
$specials= array("!","@","#","$","%","^","&","*","(",")","_","-","=","+","'","\"",".",",",":",";");
$string = trim($string);
$count = 0;
for($i=0;$i if(in_array($string[$i],$specials)){
$count++;
}
}

if($count>0){
return true;
}else{
return false;
}
}

/*
* Set Error Message
* Param $string - String Mesage
*/

function setError($string)
{
$this->errorMessage = $string;
}

/*
* Get Error Message
*/

function getMessage()
{
return $this->errorMessage;
}

/*
* Validate Fields
* Validation based on field values and Rules applied
*/
function validate()
{
if(count($this->validateFields)==0 || !is_array($this->validateFields)){
return false;
}else{
$error = 0;
$fieldPos=1;
//First Validate For Empty on all fields //
foreach($this->validateFields as $key=>$val){

$checkedError = 0;
$parts = explode("/",$val);
$label = $parts[0];
$valids = explode("|",$parts[1]);
if(in_array("EMPTY",$valids) && $checkedError==0){
if($this->validateEmpty($key)){
$error++;
$this->setError("Enter Mandatory Fields ");
$checkedError = 1;
break;
}
}
$fieldPos++;

}
if($error==0){
$fieldPos=1;
foreach($this->validateFields as $key=>$val){

$checkedError = 0;
$parts = explode("/",$val);
$label = $parts[0];
$valids = explode("|",$parts[1]);
if(in_array("EMAIL",$valids)){
if(!$this->validateEmail($key) && $checkedError==0 && $error==0){
$error++;
$this->setError("Invalid email id in field -".$label."-");
$checkedError=1;
break;
}
}
if(in_array("NUMBER",$valids)){
if(!$this->validateNumeric($key) && $checkedError==0 && $error==0){
$error++;
$this->setError("Enter Numeric in field -".$label."-");
$checkedError=1;
break;
}
}
if(in_array("FILTER",$valids)){
if($this->validateSpecial($key) && $checkedError==0 && $error==0){
$error++;
$this->setError("Special chars not allowed in field -".$label."-");
$checkedError=1;
break;
}
}

if(in_array("URL",$valids)){
if(!$this->validateUrl($key) && $checkedError==0 && $error==0){
$error++;
$this->setError("Invalid website address in field -".$label."-");
$checkedError=1;
break;
}
}
$fieldPos++;
}
}

}

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


}


Using the validator class

$array = array( $name=>"LABEL1/EMPTY",
$lastname=>"LABEL2/EMPTY", $email=>"LABEL3/EMAIL|EMPTY", $url=>"LABEL4/URL",
$url1=>"LABEL5/URL|EMPTY",
);

$obj = new Validator($array);
if($obj -> validate()){
echo "Validation Success";
}else{
echo $obj->getMessage();
}
//Validator constructor takes an array input contains, the Fields and Validation criteria
ex : $name=>"Username/EMPTY|FILTER"
$name - field to be validates
Username - Caption or the bales for the $name (Just to know which field it is)
EMPTY|FILTER - validation criteria seperated by | (Multiple validation methods)