How to use Geo library to create valid Ecto Model changeset?

问题

I'm trying to use Geo library to store Geo.Point via Phoenix model changeset. My params are: {coordinates: [49.44, 17.87]} or more prefer would be {coordinates: {latitude: 49.44, longitude: 17.87}}

In iex console I tried:

iex(5)> changeset = Place.changeset(%Place{}, %{coordinates: [49.44, 17.87]})
%Ecto.Changeset{action: nil, changes: %{}, constraints: [],
 errors: [coordinates: "is invalid"], filters: %{}
 model: %Myapp.Place{__meta__: #Ecto.Schema.Metadata<:built>,
  coordinates: nil, id: nil, inserted_at: nil, updated_at: nil}, optional: [],
 opts: [], params: %{"coordinates" => [49.445614899999995, 17.875574099999998]},
 repo: nil, required: [:coordinates],

All other attempts ended by Poison.Parser errors.

How should looks params from client side to create valid changeset?

Model:

defmodule MyApp.Place do
  use MyApp.Web, :model

  schema "place" do
    field :coordinates, Geo.Point

    timestamps
  end

  @required_fields ~w(coordinates)
  @optional_fields ~w()

  def changeset(model, params \\ :empty) do
    model
    |> cast(params, @required_fields, @optional_fields)
  end
end

回答1:

According to the tests for the library:

https://github.com/bryanjos/geo/blob/351ee6c4f8ed24541c9c2908f615e7b0a238f010/test/geo/ecto_test.exs#L100

You need to pass a Geo.Point to your changeset function:

changeset = Place.changeset(%Place{}, %{coordinates: %Geo.Point{coordinates: {49.44, 17.87}})

You can read more about custom ecto types in [the docs].(https://hexdocs.pm/ecto/Ecto.Type.html#content)

回答2:

For future reader, there is also geo_postgis, by the same author and based on geo, which is a postgrex extension and works with ecto.

来源：https://stackoverflow.com/questions/33870732/how-to-use-geo-library-to-create-valid-ecto-model-changeset

标签

PostGIS

elixir

phoenix-framework

ecto