Domo.Changeset (Domo v1.5.3) View Source
Validation functions for Ecto.Changeset.
The Ecto
schema changes can be validated to conform to types in t()
and to fulfill appropriate preconditions.
defmodule User do
use Ecto.Schema
use Domo, skip_defaults: true
import Ecto.Changeset
import Domo.Changeset
schema "users" do
field :first_name, :string
field :last_name, :string
field :age, :integer
end
@type t :: %__MODULE__{
first_name :: String.t() | nil,
last_name :: String.t(),
age :: age()
}
@type age :: pos_integer()
precond age: &validate_age/1
@max_age 150
defp validate_age(age) when age < @max_age, do: :ok
defp validate_age(_age), do: {:error, "age should be in 1..#{@max_age}"}
def changeset(user, attrs) do
user
|> cast(attrs, typed_fields())
|> validate_required(required_fields())
|> validate_type(maybe_filter_precond_errors: true)
end
end
The skip_defaults: true
option disables the validation of defaults
to match to t()
type at compile time. That is useful because any Ecto schema
has all fields set to nil
by default.
typed_fields/1
and required_fields/1
are added automatically to
the current module by using Domo.
The first_name
field is not required to have a value in the changeset
because it has nil
as one of the possible types defined.
validate_type/2
function automatically adds type ensurance errors to the
changeset. The maybe_filter_precond_errors: true
option enables
the filtering of the precondition error message for :age
field.
That error is ready to be communicated to the user.
Link to this section Summary
Functions
Validates schemaless changeset changes to conform to the schema's t()
type
and fulfill preconditions.
Validates changeset changes to conform to the schema's t()
type and fulfill
preconditions.
Link to this section Functions
Validates schemaless changeset changes to conform to the schema's t()
type
and fulfill preconditions.
Similar to validate_type/2
.
struct
is a module name providing t()
type and preconditions for changes
validation.
Examples
{%{}, %{first_name: :string, last_name: :string, age: :integer}}
|> cast(%{last_name: "Doe", age: 21}, [:last_name, :age])
|> validate_schemaless_type(User)
Validates changeset changes to conform to the schema's t()
type and fulfill
preconditions.
The function performs validations within the call to Ecto's
validate_change/3
. In case there's at least one error, the list of errors
will be appended to the :errors
field of the changeset
and the :valid?
flag will be set to false
.
The function raises a RuntimeError
if some of the changed fields are not defined
in the t()
type.
Options
:fields
- the list of changed fields that should be validated:maybe_filter_precond_errors
- when set totrue
the function returns first error received from the precondition function for each field. In case if no precondition function is defined for the field type, then autogenerated error will be returned.:take_error_fun
- function returning most relevant error from the list of errors for a field. Works whenmaybe_filter_precond_errors: true
is given. It can be useful in cases when several precondition errors are returned for the given field. By default it'sfn list -> List.first(list) end
.
Examples
%User{}
|> cast(%{last_name: "Doe", age: 21}, [:last_name, :age])
|> validate_type()