exvalidate is a dependency that validates data in the form of maps from a data scheme. It is intended to make two types of validations. The first one is plug validation, in which there is created a middleware that we insert in our router and simply adding the private keyword with a scheme in each route we will be able to validate the data before they enter the controller. What makes that our controller only gets data correctly validated. The second part is to be able to validate the data in any part of a module, for this part there is the macro "validate".

Installation

The package can be installed by adding exvalidate to your list of dependencies  in mix.exs:

def deps do
  [
    {:exvalidate, "~> 0.0.2"}
  ]
end

Use as a Plug

If you want use exvalidate as a plug, add the next lines to your plug router  file:

  alias Exvalidate.Plug, as: PlugValidate
  alias Exvalidate.PlugError

  plug(:match)
  plug(PlugValidate, on_error: &PlugError.json_error/2)
  plug(:dispatch)

You can change the on_error handler function according your requirements: - return a json: &PlugError.json_error/2 - return plain text: &PlugError.plain_error/2 - custom: you can use a custom function. This function has to return a  Plug.Conn object.

Finally, for the changes to take effect, you have add the next line in the  router api:

- To validate a query string request

  get "/test", private: %{validate_query: @schema}

- To validate a body request

  get "/test", private: %{validate_body: @schema}

Validate data

If you only want to validate data you can do so by:

- adding the alias to the file: 

- calling the validate function, where data is a map with the data to validate and the schema is the validate schema to use for data validation:

Validation rules (SCHEMA)

You can use the following rules to validate data:

- required: Setting :required to true will cause a validation error when a field is not present or the value is nil or "". 

• between: The field under validation must have a size between the given min and max. (you can validate strings, numbers, lists and tuples).

[
    name: [between: {2, 5}]
]

- default: if this rule has a value, use it, if not assign it the default value.

[
    name: [default: "Vegeta"]
]

• email: return ok if email is valid, an error if is invalid.

- in: Validate that the value or list of values belongs to the given list. (you can validate strings, numbers and lists).

[
    name: [in: ["Vegeta", "Picolo", "Krilin"]]
]

- length: Validate that the param has the given length. (Can be used with lists or strings)

- max_length: Validates the parameter is <= to the given value. (Can be used with lists, strings or tuples).

[
    name: [max_length: 5]
]

- min_length: Validates the parameter is >= to the given value. (Can be used with lists, strings or tuples).

[
    name: [min_length: 5]
]

• accepted: The field under validation must be "yes", "on", 1, or true.

[
    accept_conditions: [:accepted]
]

• type: This validation check the type of variable. (Can be used to validate string, list, map, tuple, number, integer, float, atom, boolean).

[
    name: [type: :string]
]

• nullable: Validate a field is nil or empty string.

• password: Validate a field is a valid password.

[
    password: [:password]
]

or

[
    password: [password: :CUSTOM_REGEX]
]

• IpV4: Validate a field is a ip v4 valid.

Error messages

we return an string of an error, however you want to receive the atom code, you can add to your config file the next line:

config :exvalidate, show_messages: true

Complete example

schema = [
    id: [:required, :number],
    name: [:required, type: :string, max_length: 12, min_length: 2]
]

data = %{
    "id" => 35,
    "name" => "Vegeta"
}

validate(data, schema)