Getting conn in a model with Phoenix Framework?

Question

I'm trying to create a many to many relationship using the current user assignment in the connection. The problem is I don't have access to conn in the model. I've tried passing it with the changeset, but that didn't seem like the right way to do it.

What's the best way to handle this? I imagine I can import conn into models. Is there any reason I wouldn't want to do that?

Here is what my changeset looks like right now

def changeset(model, user, params \\ :invalid) do
    model
    |> cast(params, @required_fields)
    |> put_assoc(:users, [user])
    |> validate_required([:name])
    |> unique_constraint(:name)
end

UPDATE

Ended up going with Steve's suggestion. Added a virtual field for the user id to the schema and this function to the changeset pipeline

  def changeset(model, params \\ :invalid) do
    model
    |> cast(params, @required_fields)
    |> associate_current_user(params)
    |> validate_required([:name])
    |> unique_constraint(:name)
  end

  def associate_current_user(model, params) do
    case params do
      %{"user_id" => id} ->
        user = Repo.get!(User, id)

        model
        |> put_assoc(:users, [user])
      _ ->
        model
    end
  end

Steve Pallen Steve Pallen · Accepted Answer · 2017-04-19T06:40:37

Why don't you just add the current user_id into the params and handle it that way. If the new/update is coming from a web form, its easy to get current_user in the template and add a hidden input.

Getting conn in a model with Phoenix Framework?

2 Answers