PHP Validation Class

A simple PHP input validation class. Extend it for extra functionality.

Download the Validation Class from Github

Validation.php

/**
 * Simple Input Validation Class
 * @author Zayn Ali https://www.facebook.com/zaynali53
 * @link   https://github.com/zaynali53/Validation
 */
class Validation {

    protected $errors = array();

    /**
     * Get validation errors for custom display
     * @return array
     */
    public function get_errors() {
        return $this->errors;
    }

    /**
     * Show Ordered/Un-ordered list of Generated Errors
     * @param  array   $attributes
     * @param  boolean $ordered_list
     * @return void
     */
    public function show_errors($attributes = array(), $ordered_list = FALSE) {
        if ( ! is_array($attributes)) {
            trigger_error('show_errors expects $attributes to be an array.');
            return;
        }

        if ( ! is_bool($ordered_list)) {
            trigger_error('show_errors expects $ordered_list to be a boolean.');
            return;
        }

        $tag = ($ordered_list == TRUE) ? "ol" : "ul";
        
        $output = "<$tag";
            foreach ($attributes as $key => $value) {
                $output .= " $key=\"$value\"";
            }
        $output .= ">";

        foreach ($this->errors as $error) {
            $output .= "
" . $error . "
";
        }
        
        $output .= "";

        echo $output;
    }

    /**
     * Validates the data with the given set of rules
     * @param  array $data
     * @param  array $rules
     * @return bool
     */
    public function validate($data, $rules) {
        if ( ! is_array($data)) {
            trigger_error('validate expects $data to be an array.');
            return;
        }

        if ( ! is_array($rules)) {
            trigger_error('validate expects $rules to be an array.');
            return;
        }

        $valid = TRUE;

        foreach ($rules as $field_name => $rules_str) {
            $rules_arr = explode('|', $rules_str);

            foreach ($rules_arr as $rule) {
                $value = isset($data[$field_name]) ? $data[$field_name] : NULL;

                if (preg_match('/:/', $rule)) {
                    $sub_rule = explode(':', $rule);
                    if ($this->$sub_rule[0]($value, $field_name, $sub_rule[1]) === FALSE)
                        $valid = FALSE;
                } else {
                    if ($this->$rule($value, $field_name) === FALSE)
                        $valid = FALSE;
                }
            }
        }

        return $valid;
    }

    /**
     * Email filter rule
     * @param  string $value
     * @param  string $field_name
     * @param  string $domain
     * @return bool
     */
    protected function email($value, $field_name, $domain = NULL) {
        if ( ! is_null($domain)) {
            $specific = "@$domain";
            $verified = ($specific == substr($value, strpos($value, $specific)));
            if (filter_var($value, FILTER_VALIDATE_EMAIL) && $verified === FALSE)
                $this->errors[] = $field_name . " needs to be a valid E-Mail.";
            return $verified;
        }

        $valid = filter_var($value, FILTER_VALIDATE_EMAIL);
        if ($valid === FALSE)
            $this->errors[] = $field_name . " needs to be a valid E-Mail.";
        return $valid;
    }

    /**
     * Required field rule
     * @param  string $value
     * @param  string $field_name
     * @return bool
     */
    protected function required($value, $field_name) {
        $valid = !empty($value);
        if ($valid === FALSE)
            $this->errors[] = $field_name . " is required.";
        return $valid;
    }

    /**
     * Minimum Length of the string rule
     * @param  string $value
     * @param  string $field_name
     * @param  int    $length
     * @return bool
     */
    protected function min_length($value, $field_name, $length) {
        $valid = TRUE;
        if ( ! is_numeric($length)) {
            trigger_error('min_length Param: $length must be a number');
            return;
        }

        if (trim(strlen($value)) < (int) $length) {
            $valid = FALSE;
            $this->errors[] = $field_name . " Minimum Length must be " . $length;
        }
        return $valid;
    }

    /**
     * Maximum Length of the string rule
     * @param  string $value
     * @param  string $field_name
     * @param  int    $length
     * @return bool
     */
    protected function max_length($value, $field_name, $length) {
        $valid = TRUE;
        if ( ! is_numeric($length)) {
            trigger_error('max_length Param: $length must be a number');
            return;
        }

        if (trim(strlen($value)) > (int) $length) {
            $valid = FALSE;
            $this->errors[] = $field_name . " Maximum Length must be " . $length;
        }
        return $valid;
    }

    /**
     * White list filter rule
     * @param  string $value
     * @param  string $field_name
     * @param  string $white_list_string
     * @return bool
     */
    protected function white_list($value, $field_name, $white_list_string) {
        $white_list = explode(',', $white_list_string);
        $valid = in_array($value, $white_list);
        if ($valid === FALSE)
            $this->errors[] = $field_name . " is invalid";
        return $valid;
    }

}

Usage of class. Index.php.

Create a simple form for demonstration.

    
        
        
    
    
        

            Email:  

            Password:  

            
            
        
    

On the top of Index.php.

Check the Posted data and then require the validation class.
Add the validation rules in an array (input field names as keys) and rules as value separating with pipe | and sub-rule with colon :
Create an object of the Validation class.
Check if the method validate returns TRUE then echo out the results other wise use get_errors method to display errors.

if ($_POST) {
    require_once 'class.Validation.php';

    $rules = array(
        'email' => 'required|email:zaynali.com',
        'password' => 'required|min_length:8|max_length:30',
        'environment' => 'required|white_list:admin,user,guest'
    );

    $validation = new Validation();

    if ($validation->validate($_POST, $rules)) {
        // Validated Data
        echo "
", print_r($_POST), "
";
    } else {
        $validation->show_errors(['id' => 'errors', 'class' => 'errors'], TRUE);
    }
}