Laravel 5.x Custom Validation Rule: startswith

startswith.php

// validate that mobile number starts with '07'
$rules = [
  'mobile'  => 'required|numeric|startswith:07',
];
		
// custom validator called startswith
Validator::extend('startswith', function( $attribute, $value, $parameters ) {
  return substr( $value, 0, strlen( $parameters[0] ) ) == $parameters[0];
});

// custom replacer, so we can replace :value in the message
Validator::replacer('startswith', function( $message, $attribute, $rule, $parameters ) {
  return str_replace( [':value'], $parameters, $message );
});

// Error message for startswith failure
$messages = [ 'startswith' => ':attribute needs to starts with :value' ];

// validate input
$validation = Validator::make( Input::all(), $rules, $messages );