This snippet is useful if you need to validate a telephone number using an editable list with specific formats.

<?php
/*
string validate_telephone_number (string $number, array $formats)
*/

function validate_telephone_number($number, $formats)
{
$format = trim(ereg_replace("[0-9]", "#", $number));

return (in_array($format, $formats)) ? true : false;
}

/* Usage Examples */

// List of possible formats: You can add new formats or modify the existing ones

$formats = array('###-###-####', '####-###-###',
				 '(###) ###-###', '####-####-####',
				 '##-###-####-####', '####-####', '###-###-###',
				 '#####-###-###', '##########');

$number = '08008-555-555';

if(validate_telephone_number($number, $formats))
{
echo $number.' is a valid phone number.';
}

echo "<br />";

$number = '123-555-555';

if(validate_telephone_number($number, $formats))
{
echo $number.' is a valid phone number.';
}

echo "<br />";

$number = '1800-1234-5678';

if(validate_telephone_number($number, $formats))
{
echo $number.' is a valid phone number.';
}

echo "<br />";

$number = '(800) 555-123';

if(validate_telephone_number($number, $formats))
{
echo $number.' is a valid phone number.';
}

echo "<br />";

$number = '1234567890';

if(validate_telephone_number($number, $formats))
{
echo $number.' is a valid phone number.';
}
?>

In this tutorial I will show you how to create an image validator script. You can choose between 2 methods of validation: one that will verify if the file is actually an image, by checking the file’s mime-type, and the other one which checks the extension of the uploaded file.

Let’s start creating the configuration file:

config.php

<?php
/* 
1 = Check if the file uploaded is actually an image no matter what extension it has
2 = The uploaded files must have a specific image extension
*/

$validation_type = 1;

if($validation_type == 1)
{
	$mime = array('image/gif' => 'gif',
                  'image/jpeg' => 'jpeg',
                  'image/png' => 'png',
                  'application/x-shockwave-flash' => 'swf',
                  'image/psd' => 'psd',
                  'image/bmp' => 'bmp',
                  'image/tiff' => 'tiff',
                  'image/tiff' => 'tiff',
                  'image/jp2' => 'jp2',
                  'image/iff' => 'iff',
                  'image/vnd.wap.wbmp' => 'bmp',
                  'image/xbm' => 'xbm',
                  'image/vnd.microsoft.icon' => 'ico');
}
else if($validation_type == 2) // Second choice? Set the extensions
{
	$image_extensions_allowed = array('jpg', 'jpeg', 'png', 'gif','bmp');
}

$upload_image_to_folder = 'images/';
?>

Now let’s create the form that will help us to upload the file:

<form enctype="multipart/form-data" action="validate_image_upload.php" method="POST">
    
<!-- MAX_FILE_SIZE must be set before the input element -->
<input type="hidden" name="MAX_FILE_SIZE" value="2048000" />

<!-- The name from the $_FILES array is determined by the input name -->
Select an Image: <input name="image_file" type="file" /> 
<input type="submit" value="Upload" />

</form>

Our form will send the data to validate_image_upload.php. Here, the script will check the type of validation. If the file is validated the user will see a successful submission message and the file will be moved in the specified image folder. The uploaded file failed to pass the validation process? In this case, it will be deleted and the script will output an error message.

Read more from this entry…

This is a useful function if you need to validate a password (input). If you have a form and you need to check if the username, which is registering, entered a valid password (without illegal characters) then this would help you to do it. Only letters, numbers and underscores are accepted.

<?php
/*
Credits: http://www.bitrepository.com/
*/

// default chars values are defined
function validate_password($password, $min_char = 4, $max_char = 20)
{
// Remove whitespaces from the beginning and end of a string
$password = trim($password); 

// Accept only letters, numbers and underscore
$eregi = eregi_replace('([a-zA-Z0-9_]{'.$min_char.','.$max_char.'})', 
'', $password);

if(empty($eregi))
	{
	return true;
	}
	else
	{
	return false;
	}
}

$password = 'my_password_123';

/*
First parameter: Password
Second parameter: Minimum chars 
Third parameter: Maximum chars
*/

$validator = validate_password($password, 4, 20);

if($validator) 
{
// Our current example will return true
echo 'The password is valid.';
}
else 
{
/* if our password value is for instance: my_@#%_password 
our function will return false */
echo 'The password appears to be invalid. 
It should contain only letters, numbers and underscore.';
}
?>