ExkPasswd.Validator behaviour (ExkPasswd v0.2.0)

Behaviour for custom configuration validators.

Implement this behaviour to add custom validation logic to your configurations. Validators are called after schema validation passes.

Implementing a Validator

Create a module that implements the validate/1 callback:

defmodule MyApp.CorporateValidator do
  @behaviour ExkPasswd.Validator

  @impl true
  def validate(config) do
    cond do
      config.num_words < 4 ->
        {:error, "Corporate policy requires at least 4 words"}

      config.separator not in ["-", "_"] ->
        {:error, "Corporate policy allows only - or _ separators"}

      true ->
        :ok
    end
  end
end

Using Validators

Pass validators to ExkPasswd.Config.new!/1 via the :validators option:

config = ExkPasswd.Config.new!(
  num_words: 4,
  separator: "-",
  validators: [MyApp.CorporateValidator]
)

Multiple validators are applied in sequence. All must return :ok for the configuration to be valid.

Callback

The behaviour requires a single callback:

validate(config) - Returns :ok or {:error, reason}

Summary

Callbacks

validate(t)

Validate a configuration.

Functions

run_all(config, list)

Run a list of validators against a configuration.

Callbacks

validate(t)

@callback validate(ExkPasswd.Config.t()) :: :ok | {:error, String.t()}

Validate a configuration.

Implementations should inspect the config and return :ok if valid, or {:error, reason} with a descriptive error message if invalid.

Parameters

config - The %ExkPasswd.Config{} struct to validate

Returns

:ok if the configuration passes validation
{:error, reason} if invalid, where reason is a descriptive string

Functions

run_all(config, list)

@spec run_all(ExkPasswd.Config.t(), [module()]) :: :ok | {:error, String.t()}

Run a list of validators against a configuration.

Each validator module must implement the ExkPasswd.Validator behaviour. Validators are called in order; the first failure stops execution.

Parameters

config - The %ExkPasswd.Config{} struct to validate
validators - List of modules implementing ExkPasswd.Validator

Returns

:ok if all validators pass
{:error, reason} from the first validator that fails

Examples

iex> defmodule TestVal do
...>   @behaviour ExkPasswd.Validator
...>   @impl true
...>   def validate(_config), do: :ok
...> end
...>
...> ExkPasswd.Validator.run_all(%ExkPasswd.Config{}, [TestVal])
:ok