Error during passing more arguments to function delete in controller

Phoenix Forum Questions / Help
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1

Hello,

I have a function in my rack_detail_controller:

  def delete(conn, %{"id" => id, "rack_id" => rack_id}) do   
    rack_detail = Repo.get!(Rack_detail, id)
    Repo.delete!(rack_detail)
    conn
      |> redirect to: "/rack_details/#{rack_id}"
  end

In my show.html.eex there’s:

link "", to: rack_detail_path(@conn, :delete, rack_detail.rack_details_id, rack_detail.rack_id), method: :delete, data: [confirm: "Are you sure?"], class: "icon-trash-empty delete-button"

The show.html.eex doesn’t even want to load itself and the error displays:

[error] #PID<0.404.0> running MdbmsWeb.Endpoint (cowboy_protocol) terminated
Server: localhost:4000 (http)
Request: GET /rack_details/1
** (exit) an exception was raised:
    ** (Protocol.UndefinedError) protocol Enumerable not implemented for 1. This protocol is implemented for: DBConnection.PrepareStream, DBConnection.Stream, Date.Range, Ecto.Adapters.SQL.Stream, File.Stream, Function, GenEvent.Stream, HashDict, HashSet, IO.Stream, List, Map, MapSet, Postgrex.Stream, Range, Scrivener.Page, Stream

Is it possible to pass 2 values (rack_detail.rack_details_id and rack_detail.rack_id) to function delete in controller?

2

Please share your router. The rate_detail_path will only work as you called it if you nested the rack resource within it, but we need to see your router to say for sure.

1 Like
3

Here’s my router

  scope "/", MdbmsWeb do
    pipe_through [:browser, :browser_auth]
    resources "/connections", PageController
    resources "/rack_details", RackDetailController, only: [:show, :delete]
    get "/connections", PageController, :index
  end
4

Is RackDetail a resource? If so, it seems like you want something like:

resources "/rack_details", RackDetailController do
  resources "/racks", RackController, only: [:show, :delete]
end

If “rack detail” and “rack” are one in in the same resource, then it seems you want to call:

rack_detail_path(@conn, :delete, rack_id)
5

I didn’t mention that the whole show.html.eex looks like this:

<%= for rack_detail <- @rack_details do %>
<%= link "", to: rack_detail_path(@conn, :delete, rack_detail.rack_details_id, rack_detail.rack_id), method: :delete, data: [confirm: "Are you sure?"], class: "icon-trash-empty delete-button" %>
<% end %>

That’s why I write rack_detail.rack_details_id etc. When I remove this second value (rack_detail.rack_id) and remove it also from controller everything works fine. The problem appears only when I add the second value to the link.

6

Right, but we need to know what your resources represent. In my previous example, you either need one of those two options, but it will depend on what a @rack_detail or a @rack is. If they are different entities with a has_many relationship, you need the nested route in order to use the rack_detail_path that you provided. If they are the same entity, which is implied by your routes, then you can only pass one resource. Your _id's imply they are different resources, but your routes don’t show that. Can you clarify? Thanks!

1 Like
7

Yes, you’re right. I apologize for the lack of details.
rack.ex

  schema "racks" do
    field :avbl_u, :string
    field :details, :string
    field :max_u, :string
    field :name, :string
    has_many :rack_detail, Mdbms.Rack_detail
    timestamps()
  end

rack_detail.ex

  schema "rack_details" do
    field :order, :string
    belongs_to :rack, Mdbms.Rack, foreign_key: :rack_id
    timestamps()
  end

I hope it’ll help you.

8

We still don’t have enough info, but from what I can tell, it sounds like you simply want rack_detail_path(@conn, :delete, rack_detail.rack_details_id)

1 Like
9

When I put to my code:

rack_detail_path(@conn, :delete, rack_detail.rack_details_id)

everything works fine.

But I also want to pass rack_detail.rack_id to use it in my controller function to redirect, because the URL consists of "/rack_details/ + rack_id and thanks to that rack_id there are displayed devices in the show.html.eex which rack_id == this rack_id.

There’s my def show from rack_detail_controller.ex:

  def show(conn, %{"id" => id}) do
    rack_details = Rack
    |> Rack.rackDetailsQuery(id)
    |> Repo.all

    render(conn, "show.html", rack_details: rack_details)
  end

The function rackDetailsQuery (query) selects all the needed information basing on rack_id forwarded in URL.

To sum up, I need both rack_id and rack_details_id. The first one to redirect after deleting and the second one to just delete the rack_detail which id == rack_details_id

I hope this information will help you understand my issue.