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@smpallen99
Created May 15, 2017 05:26
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Example ExAdminRedux Ecto Schema Adapter
defmodule ExAdmin.Schema.Adapters.Ecto do
@moduledoc """
Implements the ExAdmin.Scheam.Adapters behaviour.
Add support for Ecto in ExAdin.
"""
@behaviour ExAdmin.Schema.Adapters
@doc """
Retrieve the primay key of a query, schema module, or a schema struct.
## Examples
iex> primary_key from b in Blog
:id
iex> primary_key Blog
:id
iex> primary_key %Blog{}
:id
"""
def primary_key(%Ecto.Query{from: {_, mod}}) do
primary_key mod
end
def primary_key(module) when is_atom(module) do
case module.__schema__(:primary_key) do
[] -> nil
[key | _] -> key
end
end
def primary_key(resource) do
cond do
Map.get(resource, :__struct__, false) ->
primary_key resource.__struct__
true -> :id
end
end
@doc """
Retrieve the id value of a schema struct.
iex> get_id %Tag{name: "elixir"}
"elixir"
"""
def get_id(resource) do
Map.get(resource, primary_key(resource))
end
@doc """
Retrive type of a schem field.
## Examples
iex> type((from u in User), :email)
:string
iex> type(User, :id)
:binary_id
iex> type(%User{}, :login_count)
:integer
"""
def type(%Ecto.Query{from: {_, mod}}, key), do: type(mod, key)
def type(module, key) when is_atom(module) do
module.__schema__(:type, key)
end
def type(resource, key), do: type(resource.__struct__, key)
@doc """
TBD
"""
def get_intersection_keys(resource, assoc_name) do
resource_model = resource.__struct__
%{through: [link1, link2]} = resource_model.__schema__(:association, assoc_name)
intersection_model = resource |> Ecto.build_assoc(link1) |> Map.get(:__struct__)
[
resource_key: resource_model.__schema__(:association, link1).related_key,
assoc_key: intersection_model.__schema__(:association, link2).owner_key
]
end
end
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