6. Validation - caligrafy/caligrafy-quill Wiki

Data validation is key to the success of any application. This framework provides a tight integration with GUMP - a third party library that makes data validation easy and painless.

Learn more about GUMP here

GUMP provides two powerful features that are the cornerstones for keeping the data clean and secure: validation and filtering. Both mechanisms use built-in rules that are easy to use and apply based on the type of data.

Data Validation

Validation is about checking that the input follows the rules that the application is expecting. It is intended to avoid undesired data that could ultimately cause errors or introduce security vulnerabilities.

Validator Methods

There are 3 controller methods that could help validate inputs that we suggest using.

   
   public function validate($inputArray, $ruleArray); 
   // This methods validates the input array based on a set of rules and returns true or errors
   
   public function $this->validator->is_value($inputArrray, $ruleArray, $customMessageArray); 
   // This method validates the input array and uses custom error messages

   public function check(Array $inputArray, Array validation_rules, Array filtering_rules); 
   // This method combines both validation and filtering (more on this later)

Validators

GUMP relies on a set of rules - the Validators - to do this validation. Below is a curated list of the available Validators.

  • required Ensures the specified key value exists and is not empty
  • required_file Ensures that a file is specified
  • valid_email Checks for a valid email address
  • max_len,n Checks key value length, makes sure it's not longer than the specified length. n = length parameter.
  • min_len,n Checks key value length, makes sure it's not shorter than the specified length. n = length parameter.
  • exact_len,n Ensures that the key value length precisely matches the specified length. n = length parameter.
  • alpha Ensure only alpha characters are present in the key value (a-z, A-Z)
  • alpha_numeric Ensure only alpha-numeric characters are present in the key value (a-z, A-Z, 0-9)
  • alpha_dash Ensure only alpha-numeric characters + dashes and underscores are present in the key value (a-z, A-Z, 0-9, _-)
  • alpha_space Ensure only alpha-numeric characters + spaces are present in the key value (a-z, A-Z, 0-9, \s)
  • numeric Ensure only numeric key values
  • integer Ensure only integer key values
  • boolean Checks for PHP accepted boolean values, returns TRUE for "1", "true", "on" and "yes"
  • float Checks for float values
  • valid_url Check for valid URL or subdomain
  • url_exists Check to see if the url exists and is accessible
  • valid_cc Check for a valid credit card number (Uses the MOD10 Checksum Algorithm)
  • valid_name Check for a valid format human name
  • contains,n Verify that a value is contained within the pre-defined value set
  • min_numeric Determine if the provided numeric value is higher or equal to a specific value
  • max_numeric Determine if the provided numeric value is lower or equal to a specific value
  • date Determine if the provided input is a valid date (ISO 8601)
  • starts Ensures the value starts with a certain character / set of character
  • phone_number Validate phone numbers that match the following examples: 555-555-5555 , 5555425555, 555 555 5555, 1(519) 555-4444, 1 (519) 555-4422, 1-555-555-5555
  • regex You can pass a custom regex using the following format: 'regex,/your-regex/'
  • valid_json_string validate string to check if it's a valid json format

See the full list of GUMP Validators here

Usage

Validation can be used within the context of a Controller or any class in the /application folder. This framework integrated the main methods of GUMP into one common method.

Let's take the example of a User model that has a username and a password. Both the username and the password are required. The username must be alphanumeric and the password should be between 6 and 100 characters.

use Caligrafy\Controller;

class UserController extends Controller {
    public function read()
    {
 
       /* Validate the inputs using the check the inputs according to the described rules 
        * @param array inputArray is the array of inputs
        * @param array field => rule
        * @return true if validation is successful. Otherwise an array of error messages is returned for each erroneous field
        */
       $result = $this->check($inputArray, array(
                    'username' => 'required|alpha_numeric',
	            'password' => 'required|max_len,100|min_len,6')
       );

       // Alternatively, you can use the validate method
      $result = $this->validate($inputArray, array(
                    'username' => 'required|alpha_numeric',
	            'password' => 'required|max_len,100|min_len,6')
       );

       // With Custom Error messages
      $result = $this->validator->is_valid($inputArray, 
                array(
                    'username' => 'required|alpha_numeric',
	            'password' => 'required|max_len,100|min_len,6')
                ),
                array(
                    'username' => ['required' => 'Username is required']
                )
              );

       // Checking if valid
       if ($result !== true) {
           return $result;
       } else {//...}
    }
}

Data Filtering

Filtering is used to make sure that the data is clean, sanitized and that it does not cause any undesired errors or security vulnerabilities. Unlike validation that is meant to either accept or reject the data, filtering is meant to modify the data and clean it from undesirable formats.

Filters

GUMP relies on a set of filtering rules - the Filters. Filters can be any PHP functions that return a string. According to the GUMP documentation, you don't need to create your own if a native PHP function exists that does what you want the filter to do. Below is a curated list of the available Filters.

  • sanitize_string Remove script tags and encode HTML entities, similar to GUMP::xss_clean();
  • urlencode Encode url entities
  • htmlencode Encode HTML entities
  • sanitize_email Remove illegal characters from email addresses
  • sanitize_numbers Remove any non-numeric characters
  • sanitize_floats Remove any non-float characters
  • trim Remove spaces from the beginning and end of strings
  • base64_encode Base64 encode the input
  • base64_decode Base64 decode the input
  • sha1 Encrypt the input with the secure sha1 algorithm
  • md5 MD5 encode the input
  • noise_words Remove noise words from string
  • json_encode Create a json representation of the input
  • json_decode Decode a json string
  • rmpunctuation Remove all known punctuation characters from a string
  • basic_tags Remove all layout orientated HTML tags from text. Leaving only basic tags
  • whole_number Ensure that the provided numeric value is represented as a whole number
  • ms_word_characters Converts MS Word special characters [“”‘’–…] to web safe characters
  • lower_case Converts to lowercase
  • upper_case Converts to uppercase
  • slug Creates web safe url slug

Usage

Filtering can be used within the context of a Controller or any class in the /application folder. This framework integrated the main methods of GUMP into one common method.

Let's take the example of a User model that has a username and a password. Both the username and password need to be trimmed (remove extra spaces) and sanitized in order to make sure that no scripts are included in them. This is a great way to use filters.

use Caligrafy\Controller;

class UserController extends Controller {
    public function read()
    {

       /* Validate the inputs using the check the inputs according to the described rules 
        * @param array inputArray is the array of inputs
        * @param array validation is array() by default if no validation is needed
        * @param array field => filter_rules
        * @return array filtered results
        */
       $result = $this->check($inputArray, array(), array(
                    'username' => 'trim|sanitize_string',
	            'password' => 'trim|sanitize_string')
       );

       // Alternatively, you can use the filter method
       $result = $this->filter($inputArray, array(
                    'username' => 'trim|sanitize_string',
	            'password' => 'trim|sanitize_string')
       );       
    }
}

Notice that the 2nd argument of the check method is an empty array. This is because it is a combined routine that could execute both validation and/or filtering.

Validation & Filtering

The check method is a framework method that makes the usage of the GUMP validator more straightforward.

public function check(Array $inputArray, Array validation_rules, Array filtering_rules);

The check method accepts 3 arrays:

  1. the input array to be checked
  2. validation array
  3. filtering array.
  • When both arrays are provided, the check function filters and validates at once. If the validation succeeds, it returns an array of the filtered fields. If the validation fails, it returns an array of the erroneous fields with their respective error messages.
  • When the validation array is given but not the filtering array, the method performs a validation as described earlier.
  • When the filtering array is given but not the validation array, the method performs a filter as described earlier.

GUMP provides more elaborate features to create custom validations and filters. For more details, consult the GUMP library documentation here

File Validation

If your application requires uploading files, you might want to validate the files before accepting that. Using the same check method, you can use the built-in rules to perform this validation.

use Caligrafy\Controller;

class UserController extends Controller {
    public function read()
    {
       // Validate the $_FILES inputs
       $result = $this->check($_FILES, array(
	'image' => 'required_file|extension,png;jpg')
       );
    }
}



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