LuaValidation

Validation library for Lua with fluent API and error message handling inspired by Respect\Validation.

Instalation

You can install it by using LuaRocks.

luarocks install validation

Usage

The fluent API of library follows the same principles of Respect\Validation.

Module import

After installing LuaValidation you can simple import it:

local v = require("validation")

Chained validation

It is possible to use validators in a chain.

v.numeric().positive().between(1, 256)

Validation functions

There are more than only one way to perform validation against you data with LuaValidation:

• assert()
• check()
• validate()

assert()

This function validates the entire chain and produces its message.

v.numeric().positive().between(1, 256):assert(0)

The code above should produce this message:

Some rules must pass for "0"
 - "0" must be positive
 - "0" must be between "1" and "256"

check()

Works like assert() but is produces only the message of the first rule of the rule which did not pass the validation.

v.numeric().positive():check(nil)

The code above should produce this message:

"nil" must be numeric

validate()

This function returns a boolean value which says if the input is valid or not.

if v.equals("foo"):validate(input) then
  -- Do something
end

Reusable chain

Once created, you can reuse your chain anywhere:

local my_chain = v.numeric().positive().between(1, 256)

my_chain:check(first)
my_chain:check(second)
my_chain:check(third)

Custom message handler

By default you it uses error() as default message handler, but you change this behavior by defining a new messager with v.set_messager() which accepts a callback as an argument.

v.set_messager(
    function (message)
        print(">>>", message)
    end
)

Custom messages

When you use assert() and check(), you can define a custom message for you message:

v.numeric():check(nil, {message = "Something is not right"})

The above code produces this message:

Something is not right

Custom names

When you use assert() and check(), sometimes you just want to name it:

v.numeric():check(nil, {name = "Name"})

The above code produces this message:

"Name" must be numeric

Available rules

• absent(): Checks if the input is nil
• all(...): Performs validation of all rules defined on its constructor against the input
• between(minimum, maximum): Checks if the input is between minimum and maximum
• dummy(result): Performs validation exactly according to what was defined as result on its constructor
• equals(expected): Checks if the input is equal to the expected value
• key(key, rule, mandatory): Performs validation of rule against the value of key of the input. If mandatory is true (which is the default value), also checks if the key exists in the input.
• never(rule): Performs the reverse validation of the rule in the given input
• number(): Checks if the input is a number
• numeric(): Checks if the input is a numeric value
• positive(): Checks if the input is a positive value
• string(): Checks if the input is a string

There's just a few rules, but soon there will be as much as on Respect\Validation, if you want to contribute it will be a pleasure for me.