Is cast_attachments changing my params?

[MartinElvar]

When using cast_attachments/4, Phoenix seem to choke, with the following error, while rendering my form.

Request: POST /admin/companies/6
** (exit) an exception was raised:
    ** (FunctionClauseError) no function clause matching in Phoenix.HTML.Safe.Tuple.to_iodata/1
        (phoenix_html) lib/phoenix_html/safe.ex:72: Phoenix.HTML.Safe.Tuple.to_iodata({"sadfasdfasdf", %Mobil.Company{__meta__: #Ecto.Schema.Metadata<:loaded>, id: 6, inserted_at: #Ecto.DateTime<2015-09-09T15:12:24Z>, logo: %{file_name: "høstning.png", updated_at: #Ecto.DateTime<2015-09-09T15:12:24Z>}, name: nil, updated_at: #Ecto.DateTime<2015-09-09T15:12:24Z>}})
        (phoenix_html) lib/phoenix_html/tag.ex:66: anonymous fn/2 in Phoenix.HTML.Tag.tag_attrs/1
        (elixir) lib/enum.ex:1261: Enum."-reduce/3-lists^foldl/2-0-"/3
        (phoenix_html) lib/phoenix_html/tag.ex:35: Phoenix.HTML.Tag.tag/2
        (mobil) web/templates/admin/company/form.html.eex:15: anonymous fn/2 in Mobil.Admin.CompanyView.form.html/1
        (phoenix_html) lib/phoenix_html/form.ex:227: Phoenix.HTML.Form.form_for/4
        (mobil) web/templates/admin/company/form.html.eex:1: Mobil.Admin.CompanyView."form.html"/1
        (mobil) web/templates/admin/company/edit.html.eex:7: Mobil.Admin.CompanyView."edit.html"/1

As Phoenix tries to render

<%= text_input f, :name, class: "form-control" %>

Which suggest, that my name value was changed?

If i change it back to cast/4, then the problem is gone, but then i'm missing my image.

[stavro]

Can you share your cast and cast_attachments code? Currently it is designed where you need to use cast_attachments for all file attributes only. All other attributes should still be sent through cast.

[MartinElvar]

This is my model.

defmodule Mobil.Company do
  use Mobil.Web, :model
  use Arc.Ecto.Model

  schema "companies" do
    field :name, :string
    field :logo, Mobil.Logo.Type

    timestamps
  end

  @required_fields ~w(name)
  @optional_fields ~w(logo)

  @doc """
  Creates a changeset based on the `model` and `params`.

  If no params are provided, an invalid changeset is returned
  with no validation performed.
  """
  def changeset(model, params \\ :empty) do
    model
    |> cast_attachments(params, @required_fields, @optional_fields)
  end
end

So i need to split it up?

[stavro]

Yes, please split it up as such: https://github.com/stavro/arc_ecto/blob/master/test/model_test.exs#L21 and try again

[MartinElvar]

Worked wonders! Thank you @stavro

[stavro]

I will do some digging to see if there is a less confusing way to handle this... You are not the first person to make this same hiccup

[MartinElvar]

@stavro I don't know if i think that it is confusing, rather i would say the readme could be clearer.

More specific. https://github.com/stavro/arc_ecto#add-your-attachment-to-your-ecto-model

Which could explain it more like..

  schema "companies" do
    field :name, :string
    field :logo, Mobil.Logo.Type

    timestamps
  end

  @required_fields ~w(name)
  @optional_fields ~w()

  @doc """
  Creates a changeset based on the `model` and `params`.

  If no params are provided, an invalid changeset is returned
  with no validation performed.
  """
  def changeset(model, params \\ :empty) do
    model
    |> cast(params, @required_fields, @optional_fields)
    |> cast_attachments(params, ~w(), ~w(logo))
  end

[stavro]

Readme updated! Thanks.