Phoenix：无论参数如何，API 控制器都会出错

Question

我有一个如下所示的控制器：

defmodule PrefectWeb.DocumentController do
  use PrefectWeb, :controller

  alias Prefect.Queue

  def create(conn, params) do
    case Prefect.add(Queue, struct(Prefect.Document, params[:id])) do
      nil -> conn 
        |> put_status(404) 
        |> render("error.json")
      status -> {:ok, status}
    end
  end
end

create 方法应该将params[:id] 添加到Queue 进程中。我的单元测试如下所示：

defmodule PrefectWeb.DocumentControllerTest do
  use ExUnit.Case, async: true
  use PrefectWeb.ConnCase

  setup do
    params = [
      env: "test",
      id: 1,
    ]

    [params: params]
  end

  test "creation", %{conn: conn, params: params} do
    conn
    |> post(document_path(conn, :create, params))

    assert json_response(conn, 422)
  end
end

此规范返回此错误：

1) test creation (PrefectWeb.DocumentControllerTest)
   test/prefect_web/controllers/document_controller_test.exs:27
   ** (Protocol.UndefinedError) protocol Enumerable not implemented for nil. This protocol is implemented for: Date.Range, File.Stream, Function, GenEvent.Stream, HashDict, HashSet, IO.Stream, List, Map, MapSet, Range, Stream

如果我将控制器功能更改为他的：

def create(conn, %{"params" => params}) do
  ...
end

我收到此错误：

1) test creation (PrefectWeb.DocumentControllerTest)
     test/prefect_web/controllers/document_controller_test.exs:27
     ** (Phoenix.ActionClauseError) could not find a matching PrefectWeb.DocumentController.create clause
     to process request. This typically happens when there is a
     parameter mismatch but may also happen when any of the other
     action arguments do not match. The request parameters are:

       %{"env" => "test", "id" => "1"}

为什么我不能正确地将params[:id] 传递给create 方法？

更新

添加请求标头也无济于事：

|> put_req_header("content-type", "application/json")

Answer 1

参数映射是字符串而不是基于原子的。尝试将您的控制器更改为

defmodule PrefectWeb.DocumentController do
  use PrefectWeb, :controller

  alias Prefect.Queue

  def create(conn, params) do
    case Prefect.add(Queue, struct(Prefect.Document, params["id"])) do
      nil -> conn 
        |> put_status(404) 
        |> render("error.json")
      status -> {:ok, status}
    end
  end
end

和你的测试

defmodule PrefectWeb.DocumentControllerTest do
  use ExUnit.Case, async: true
  use PrefectWeb.ConnCase

  setup do
    params = %{
      "env" => "test",
      "id" => 1
    }

    [params: params]
  end

  test "creation", %{conn: conn, params: params} do
    conn
    |> post(document_path(conn, :create, params))

    assert json_response(conn, 422)
  end
end

Answer 2

您正在断言在setup 中创建的连接，而不是从post 返回的连接。尝试在断言之前重新绑定conn。

  test "creation", %{conn: conn, params: params} do
    conn = 
      conn
      |> post(document_path(conn, :create), params)

    assert json_response(conn, 422)
  end