Categories: PHP

Filter Variable In PHP

Share your learning

How to filter variable in PHP?

Today, I am here with an interesting filter variable function in PHP.

This function can help us to validate and sanitize our form inputs or simple variables.

Syntax

filter_var($variable, FILTER_TYPE, FILTER_OPTIONS)

Parameters:

The first parameter for the variable
Second for the type of filter.
The third parameter for options (optional)

This PHP function will return filtered data on the success or false on failure.

To filter the variable in PHP, we can use filter function with following filter types,

Filter Type

FILTER_SANITIZE_STRING
FILTER_FLAG_STRIP_HIGH
FILTER_FLAG_STRIP_LOW
FILTER_VALIDATE_INT
FILTER_SANITIZE_EMAIL
FILTER_VALIDATE_EMAIL
FILTER_SANITIZE_URL
FILTER_VALIDATE_URL
FILTER_VALIDATE_IP

Let’s understand this function with the help of a demo project.

How’s it sound?

You will get the source code of this project from my Github repository, link given at the end of the post.

Best age calculator with PHP OOPs

Let’s get started,

Layouts

We will create two files in layout.

Header.php

The header file is just to add CSS and required js. This is good practice to create separate layout files, it will help while working on a big project or multiple pages with the same header and footer.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    
    <!-- Add page icon -->
    <link rel="icon" href="assets/icon/sb.png" type="image/png" sizes="16x16" /> 
    <title>Filter variable with php</title>
    
    <!-- Latest compiled and minified CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" />
    
    
    <!-- Latest compiled and minified JavaScript -->
    <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
    <script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    
    <!-- Add external css  -->
    <link rel="stylesheet" href="assets/css/theme.css" />
</head>
<body>

Footer.php

Usually, we can trigger any js plugin here but for now, we don’t have any.

</body>
</html>

Index file

<?php

    include_once('layout/header.php');
    include_once('validator.php');

    $validator = new Validator();

    if($_POST) {
        $validator->SetForm($_POST);
        $validator->Validate();
    }

    $status_icon['success'] = '<span class="glyphicon glyphicon-ok form-control-feedback" aria-hidden="true"></span>';
    $status_icon['error'] = '<span class="glyphicon glyphicon-remove form-control-feedback" aria-hidden="true"></span>';
    $status_icon[''] = '';
?>

<ol class="breadcrumb">
  <li><a href="https://sbsharma.com">Home</a></li>
  <li><a href="https://sbsharma.com/php">PHP</a></li>
  <li class="active">Filter var with php</li>
</ol>

    <div class="container">
        <div class="page-header">
            <h1>Filter variable with php</h1>
        </div>
        <div class="row">
            <div class="col-md-4 col-md-offset-4">
            
                <div class="panel panel-default theme-color mt-1">
                    <!-- Default panel contents -->
                    <div class="panel-heading theme-color text-center">
                        filter_var($variable, $filter_type, $options?)
                    </div>
                    <div class="panel-body">
                        <div class="alert alert-info alert-dismissible" role="alert">
                            <button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">×</span></button>
                            <strong>Info!</strong> Sanitize string only remove html tags e.g. &ltp&gt example &lt/p&gt = example
                        </div>
                        <form method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>">
                            <div class="form-group has-<?= $validator->var['string']['status'] ?> has-feedback">
                                <label class="control-label" for="str_input">String</label>
                                <input <?= $validator->var['string']['focus'] ?> name="string" value="<?= $validator->var['string']['value'] ?>" type="text" class="form-control" id="str_input" placeholder="abcd">
                                <?= $status_icon[$validator->var['string']['status']] ?>
                            </div>
                            <div class="form-group has-<?= $validator->var['integer']['status'] ?> has-feedback">
                                <label class="control-label" for="int_input">Integer</label>
                                <input <?= $validator->var['integer']['focus'] ?> name="integer" value="<?= $validator->var['integer']['value'] ?>" type="text" class="form-control" id="int_input" placeholder="123456789">
                                <?= $status_icon[$validator->var['integer']['status']] ?>
                            </div>
                            <div class="form-group has-<?= $validator->var['email']['status'] ?> has-feedback">
                                <label class="control-label" for="email_input">Email address</label>
                                <input <?= $validator->var['email']['focus'] ?> name="email" value="<?= $validator->var['email']['value'] ?>" type="email" class="form-control" id="email_input" placeholder="example@xyz.com">
                                <?= $status_icon[$validator->var['email']['status']] ?>
                            </div>
                            <div class="form-group has-<?= $validator->var['url']['status'] ?> has-feedback">
                                <label class="control-label" for="url_input">URL</label>
                                <input <?= $validator->var['url']['focus'] ?> name="url" value="<?= $validator->var['url']['value'] ?>" type="text" class="form-control" id="url_input" placeholder="https://example.com">
                                <?= $status_icon[$validator->var['url']['status']] ?>
                            </div>
                            <div class="form-group has-<?= $validator->var['ip']['status'] ?> has-feedback">
                                <label class="control-label" for="ip_input">IP Address</label>
                                <input <?= $validator->var['ip']['focus'] ?> name="ip" value="<?= $validator->var['ip']['value'] ?>" type="text" class="form-control" id="ip_input" placeholder="127.0.0.1">
                                <?= $status_icon[$validator->var['ip']['status']] ?>
                            </div>

                            <button type="submit" class="btn btn-dark">Submit</button>
                        </form>
                    </div>
                    <div class="panel-footer theme-color text-center">Powered by <a class="link-color" href="https://sbsharma.com" target="_blank">www.sbsharma.com</a>
                    </div>
                </div>    
            </div>
        </div>
    </div>

Validator class

Validator class give us a nice validated or sanitized result.

<?php


class Validator {

    public $form_data;
    public $var;
    public $form_controls;

    public function __construct() {
        $this->form_controls = ['string', 'integer', 'email', 'url', 'ip'];
    }

    public function Validate() {
        
        foreach($this->form_controls as $control) {
            $res = $this->rules($control);
            $this->var[$control] = [
                'status' => $res ? 'success' : 'error',
                'value' => $res ? $res : null, 
                'focus' => $res ? '' : 'autofocus'
            ];
        }    
    }

    public function rules($input) {
        $result = false;
        if($this->form_data) {
            $result = filter_var($this->form_data[$input], $this->filter_type($input));
        }
        return $result;
    }

    public function SetForm($data) {
        $this->form_data = $data;
    }

    protected function filter_type($input) {
        switch($input) {
            case 'string':
                return FILTER_SANITIZE_STRING;
                break;
            case 'integer':
                return FILTER_VALIDATE_INT;
                break;
            case 'email':
                return FILTER_VALIDATE_EMAIL;
                break;
            case 'url':
                return FILTER_VALIDATE_URL;
                break;
            case 'ip':
                return FILTER_VALIDATE_IP;
                break;
            default:
                return false;
                break;
        }
    }

    
}