Access Schemas

Install Deps

Mix.install([:data_schema])

We can leverage access paths when creating our structs by defining a data_accessor that uses get_in

defmodule AccessDataAccessor do
  @behaviour DataSchema.DataAccessBehaviour

  @impl true
  def field(data, path) do
    get_in(data, path)
  end

  @impl true
  def list_of(data, path) do
    get_in(data, path)
  end

  @impl true
  def has_one(data, path) do
    get_in(data, path)
  end

  @impl true
  def has_many(data, path) do
    get_in(data, path)
  end
end

Now we can define our schema:

defmodule Blog do
  import DataSchema, only: [data_schema: 1]

  @data_accessor AccessDataAccessor
  data_schema(list_of: {:comments, ["comments", Access.all(), "text"], &{:ok, to_string(&1)}})
end

And create a struct from this:

input = %{
  "content" => "This is a blog post",
  "comments" => [%{"text" => "This is a comment"}, %{"text" => "This is another comment"}],
  "draft" => %{"content" => "This is a draft blog post"},
  "date" => "2021-11-11",
  "time" => "14:00:00",
  "metadata" => %{"rating" => 0}
}

DataSchema.to_struct(input, Blog)