Filter by has_one association field

[akrisanov]

I have two models – User and Credential. My admin UI shows a list of users and has some filters on the sidebar. It's pretty easy to add a filter for a model field, but I didn't find any examples in the documentation explaining filtration mechanism for associations. Is it possible to filter user records by credential.email without hacking do_paginate_users/2 much?

@doc """
Paginate the list of users using filtrex
filters.

## Examples

    iex> list_users(%{})
    %{users: [%User{}], ...}
"""
@spec paginate_users(map) :: {:ok, map} | {:error, any}
def paginate_users(params \\ %{}) do
  params =
    params
    |> Map.put_new("sort_direction", "desc")
    |> Map.put_new("sort_field", "inserted_at")

  {:ok, sort_direction} = Map.fetch(params, "sort_direction")
  {:ok, sort_field} = Map.fetch(params, "sort_field")

  with {:ok, filter} <- Filtrex.parse_params(filter_config(:users), params["user"] || %{}),
       %Scrivener.Page{} = page <- do_paginate_users(filter, params) do
    {:ok,
     %{
       users: page.entries,
       page_number: page.page_number,
       page_size: page.page_size,
       total_pages: page.total_pages,
       total_entries: page.total_entries,
       distance: @pagination_distance,
       sort_field: sort_field,
       sort_direction: sort_direction
     }}
  else
    {:error, error} -> {:error, error}
    error -> {:error, error}
  end
end

defp do_paginate_users(filter, params) do
  User
  |> Filtrex.query(filter)
  |> order_by(^sort(params))
  |> preload(:credential)
  |> paginate(Repo, params, @pagination)
end

defp filter_config(:users) do
  defconfig do
    text :username
    date :inserted_at
  end
end

Maybe I need to extend filter_config/1 and/or Filtrex.parse_params(filter_config(:users), params["user"] || %{})?

I'm facing almost the same problem when trying to order records.

[zberkom]

@akrisanov Hey, thanks for the question! We have added support for this, but it hasn't made it's way to master yet. I'll work on adding it in early next week.

[chevinbrown]

@akrisanov will this help?
rcdilorenzo/filtrex#56

[zberkom]

@akrisanov @chevinbrown I have an open PR to add an example to the Readme as well. #97

[chevinbrown]

@zberkom will ecto 3 change this?

[zberkom]

@chevinbrown I have yet to investigate how ecto 3 will effect things. It's on my list to do though :). In the meantime if you have any insight or ideas on how it might change things, I'm all ears.

[darinwilson]

@chevinbrown @zberkom The code in #97 should still work with Ecto 3 🙂