[FEATURE-REQUEST] Allow to {:ok, conn} on `action` in any `resource_actions` to support redirect somewhere else

[ryvasquez]

Describe the problem you're proposing to solve

So I have a action in resource_actions that requires redirect to some internal page after performing the action

def resource_actions(_conn) do
    [
      approve_move_to_next: %{
        name: "Approve product and redirect somewhere",
        action: fn conn, product ->
          Product.approve(product)
          redirect(conn, to: somewhere_internal_url)
        end,
      },
    ]
  end

However action only accepts {:ok, record} | {:error, changeset} | {:error, record, custom_error} as a return value, and if you modify with the conn it will successfully redirect but raise an error something like

09:06:30.980 [error] Ranch listener SkyeWeb.Endpoint.HTTPS had connection process started with :cowboy_tls:start_link/4 at #PID<0.1179.0> exit with reason: {{:badmatch, :undefined}, [{:cow_http2_machine, :prepare_headers, 5, [file: '/Users/ryvasquez/Documents/apps/sample_app/deps/cowlib/src/cow_http2_machine.erl', line: 1119]}, {:cowboy_http2, :send_response, 5, [file: '/Users/ryvasquez/Documents/apps/sample_app/deps/cowboy/src/cowboy_http2.erl', line: 790]}, {:cowboy_http2, :commands, 3, [file: '/Users/ryvasquez/Documents/apps/sample_app/deps/cowboy/src/cowboy_http2.erl', line: 664]}, {:cowboy_http2, :loop, 2, [file: '/Users/ryvasquez/Documents/apps/sample_app/deps/cowboy/src/cowboy_http2.erl', line: 277]}, {:proc_lib, :init_p_do_apply, 3, [file: 'proc_lib.erl', line: 240]}]}

Describe the solution you'd like

Maybe we can pattern match a Plug.Conn in this part https://github.com/aesmail/kaffy/blob/c0b16cafe085638e198c7a4ad3e3afe0c31a2076/lib/kaffy_web/controllers/resource_controller.ex#L326-L337

and return as is since it was a conn.

Let me know if this is a valid solution, Im happy to work on it 👍

Describe alternatives you've considered

Additional context Add any other context or screenshots about the feature request here.

[KalleJoP]

This could also be helpful for download actions. In my case I want to generate a qr code and sent it as an download to the user.

  def resource_actions(_conn) do
    [
      generate_qr_code: %{name: "Generate QR Code", action: fn c, p -> generate_qr_code(c, p) end}
    ]
  end

  defp generate_qr_code(conn, product) do
    filename = "qr-product_id-#{product.id}.png"
    filepath = "/tmp/#{filename}"

    unverified_url(conn, "/admin/inventory/physical_product_variant/#{product.id}")
    |> QRCode.create(:high)
    |> QRCode.render(:png)
    |> QRCode.save(filepath)

    conn
    |> put_resp_header(
      "content-disposition",
      ~s(attachment; filename="#{filename}")
    )
    |> send_download({:file, filepath})
  end

[ryvasquez]

@aesmail any feedback on the request? 🙂 apologies for constantly pinging 🙇‍♂️