Dredd

Dredd judges structs; it's a validator.

Dredd was forked from Justify

Inspired heavily by Ecto.Changeset, Dredd allows you to pipe a plain map into a series of validation functions using a simple and familiar API. No schemas or casting required.

Example

dataset =
  %{email: "this_is_not_an_email"}
  |> Dredd.validate_required(:email)
  |> Dredd.validate_format(:email, ~r/\S+@\S+/)

dataset.errors #=> [email: {"has invalid format", validation: :format}]
dataset.valid? #=> false

Each validation function will return a Dredd.Dataset struct which can be passed into the next function. If a validation error is encountered the dataset will be marked as invalid and an error will be added to the struct.

Custom Validations

You can provide your own custom validations using the Dredd.add_error/4 function.

Example

defmodule MyValidator do
  def validate_color(data, field, color) do
    dataset = Dredd.Dataset.new(data)

    value = Map.get(dataset.data, :field)

    if value == color do
      dataset
    else
      Dredd.add_error(dataset, field, "wrong color", validation: :color)
    end
  end
end

Your custom validation can be used as part of a validation pipeline.

Example

dataset =
  %{color: "brown"}
  |> Dredd.validation_required(:color)
  |> MyValidator.validate_color(:color, "green")

dataset.errors #=> [color: {"wrong color", validation: :color}]
dataset.valid? #=> false

Supported Validations

• validate_acceptance/3
• validate_confirmation/3
• validate_embed/3
• validate_exclusion/4
• validate_format/4
• validate_inclusion/4
• validate_length/3
• validate_required/3
• validate_type/4

Copyright and License

Copyright (c) 2021 Anthoniy Smith

Copyright (c) 2022 Marcus Autenrieth

Dredd is licensed under the MIT License, see LICENSE.md for details.