kingofrostov / talos

Elixir parameter validation library. Simple and extensible

Talos

Talos is simple parameters validation library

Documentation can be found at ExDoc

Why another one validation library?

I needed more checks than just whether the value belonged to a particular data type.

This library allows you to define your own checks and use typical checks with a simple setup.

Usage

  defmodule CheckUserJSON do
    import Talos

    @interests_type enum(members: ["sports", "games", "food"])
    @user map(fields: [
      field(key: "email", type: string(min_length: 5, max_length: 255, regexp: ~r/.*@.*/)),
      field(key: "age", type: integer(gteq: 18, allow_nil: true)),
      field(key: "interests", type: list(type: @interests_type), optional: true)
    ])

    def validate(%{} = map_data) do
      errors = Talos.errors(@user, map_data)

      case errors == %{} do
        true -> :ok
        false -> {:error, errors}
      end
    end
  end

Somewhere in UserController

  ...

  def new_user(conn, params)
    case CheckUserJSON.valid?(params) do
       :ok -> 
          result = MyApp.register_user!(params)
          render_json(%{"ok" => true)
       {:error, errors} -> 
          render_json_errors(errors)
    end
  end
  
  ...

Own Type definition

If you want define own Type, just create module with Talos.Types behavior

defmodule ZipCodeType do
  @behaviour Talos.Types
  defstruct [length: 6]

  def valid?(%__MODULE__{length: len}, value) do
    String.valid?(value) && String.match?(value, ~r/\d{len}/)
  end

  def errors(__MODULE__, value) do
    case valid?(__MODULE__,value) do
      true -> []
      false -> ["#{value} is not zipcode"]
    end
  end
end

# And use it

Talos.valid?(%ZipCodeType{}, "123456") # => true
Talos.valid?(%ZipCodeType{}, "1234") # => false
Talos.valid?(%ZipCodeType{}, 123456) # => false

Installation

def deps do
  [
    {:talos, "~> 1.7"}
  ]
end

Contribution

Feel free to make a pull request. All contributions are appreciated!