Standard Validators Overview – Using Zend Framework 3

9.2. Standard Validators Overview

Standard ZF3 validators are provided by the Zend\Validator component ²⁹. Standard validator classes inheritance is shown in figure 9.1. As you can see from the figure, most of them are derived from AbstractValidator base class.

²⁹⁾ Here, we only consider the standard validator classes belonging to the Zend\Validator namespace. But, actually there are more validators that can be considered as standard. We will cover them in further chapters.

Figure 9.1. Validator class inheritance

Standard validators together with their brief description are listed in table 9.1. As you may notice from the table, they can be roughly divided into several groups:

validators for checking value conformance to certain format (IP address, host name, E-mail address, credit card number, etc.);
validators for checking if a numerical value lies in a given range (less than, greater than, between, etc.);
validators working as "proxies" to other validators (ValidatorChain, StaticValidator and Callback).

Table 9.1. Standard validators

Class name	Description
`EmailAddress`	Returns boolean `true` if the value is a valid E-mail address; otherwise returns `false`.
`Hostname`	Checks whether the value is a valid host name.
`Barcode`	Returns boolean `true` if and only if the value contains a valid barcode.
`CreditCard`	Returns `true` if and only if the value follows the common format of credit card number (Luhn algorithm, mod-10 checksum).
`Iban`	Returns `true` if the value is a valid International Bank Account Number (IBAN); otherwise returns `false`.
`Isbn`	Returns boolean `true` if and only if value is a valid International Standard Book Number (ISBN).
`Ip`	Returns `true` if value is a valid IP address; otherwise returns `false`.
`Uri`	Returns `true` if and only if the value is an Uniform Resource Identifier (URI).
`Between`	Returns `true` if the value lies in certain range; otherwise returns `false`.
`LessThan`	Returns boolean `true` if the value is less than certain number; otherwise returns `false`.
`GreaterThan`	Returns `true` if and only if value is greater than certain number.
`Identical`	Returns boolean `true` if the value matches a given token.
`Step`	Checks whether the value is a scalar and a valid step value.
`Csrf`	This validator checks if the provided token matches the one previously generated and stored in a PHP session.
`Date`	Returns `true` if value is a valid date of the certain format.
`DateStep`	Returns boolean `true` if a date is within a valid step.
`InArray`	Returns `true` if value is contained in the given array; otherwise returns `false`.
`Digits`	Returns boolean `true` if and only if `$value` only contains digit characters.
`Hex`	Returns `true` if and only if value contains only hexadecimal digit characters.
`IsInstanceOf`	Returns `true` if value is instance of certain class; otherwise returns `false`.
`NotEmpty`	Returns `true` if value is not an empty value.
`Regex`	Returns `true` if value matches against given pattern; otherwise returns `false`.
`StringLength`	Returns `true` if the string length lies within given range.
`Explode`	Splits the given value in parts and returns `true` if all parts pass the given check.
`StaticValidator`	This validator allows to execute another validator without explicitly instantiating it.
`Callback`	This validator allows to execute a custom validation algorithm through the user-provided callback function.
`ValidatorChain`	Wrapper validator allowing to organize several validators in a chain. Attached validators are run in the order in which they were added to the chain (FIFO).