Add failing test for multipart array parameters

test/plug/cast_test.exs

@@ -51,6 +51,34 @@
       assert OpenApiSpex.params(conn) == %{validParam: true}
     end
 
+    test "handles multipart/form-data array parameters" do
+      boundary = "----testboundary"
+
+      body = """
+      --#{boundary}\r
+      Content-Disposition: form-data; name="files[]"; filename="file1.txt"\r
+      Content-Type: text/plain\r
+      \r
+      HI\r
+      --#{boundary}\r
+      Content-Disposition: form-data; name="files[]"; filename="file2.txt"\r
+      Content-Type: text/plain\r
+      \r
+      HI2\r
+      --#{boundary}--\r
+      """
+
+      conn =
+        Plug.Test.conn(:post, "/api/upload_multipart", body)
+        |> Plug.Conn.put_req_header("content-type", "multipart/form-data; boundary=#{boundary}")
+        |> Plug.Conn.put_req_header("accept", "application/json")
+        |> OpenApiSpexTest.Router.call([])
+
+      body = Jason.decode!(conn.resp_body)
+
+      assert %{"data" => ["file1.txt", "file2.txt"]} = body
+    end
+
     @tag :capture_log
     test "invalid value" do
       conn =

test/support/router.ex

@@ -6,7 +6,7 @@ defmodule OpenApiSpexTest.Router do
   pipeline :api do
     plug :accepts, ["json"]
     plug PutApiSpec, module: OpenApiSpexTest.ApiSpec
-    plug Parsers, parsers: [:json], pass: ["text/*"], json_decoder: Jason
+    plug Parsers, parsers: [:json, :multipart], pass: ["text/*"], json_decoder: Jason
   end
 
   scope "/api" do
@@ -25,6 +25,7 @@ defmodule OpenApiSpexTest.Router do
     get "/users/:id/payment_details", OpenApiSpexTest.UserController, :payment_details
     post "/users/:id/contact_info", OpenApiSpexTest.UserController, :contact_info
     post "/users/create_entity", OpenApiSpexTest.UserController, :create_entity
+    post "/upload_multipart", OpenApiSpexTest.UploadMultipartController, :create
     get "/openapi", OpenApiSpex.Plug.RenderSpec, []
 
     resources "/pets", OpenApiSpexTest.PetController, only: [:create, :index, :show, :update]

test/support/schemas.ex

@@ -278,6 +278,29 @@ defmodule OpenApiSpexTest.Schemas do
     })
   end
 
+  defmodule UploadRequest do
+    OpenApiSpex.schema(%{
+      title: "UploadRequest",
+      description: "POST body for uploading files",
+      type: :object,
+      properties: %{
+        "files[]": %Schema{type: :array, items: %Schema{type: :string, format: :binary}}
+      },
+      required: [:"files[]"]
+    })
+  end
+
+  defmodule UploadResponse do
+    OpenApiSpex.schema(%{
+      title: "UploadResponse",
+      description: "",
+      type: :object,
+      properties: %{
+        data: %Schema{description: "Filenames", type: :array, items: %Schema{type: :string}}
+      }
+    })
+  end
+
   defmodule UserRequest do
     OpenApiSpex.schema(%{
       title: "UserRequest",

test/support/upload_multipart_controller.ex

@@ -0,0 +1,20 @@
+defmodule OpenApiSpexTest.UploadMultipartController do
+  @moduledoc tags: ["uploads"]
+
+  use Phoenix.Controller
+  use OpenApiSpex.Controller
+
+  alias OpenApiSpexTest.Schemas
+
+  plug OpenApiSpex.Plug.CastAndValidate, json_render_error_v2: true, replace_params: false
+
+  @doc request_body: {"Files", "multipart/form-data", Schemas.UploadRequest},
+       responses: [
+         created: {"Files", "application/json", Schemas.UploadResponse}
+       ]
+  def create(conn, %{"files" => files}) do
+    json(conn, %Schemas.UploadResponse{
+      data: Enum.map(files, & &1.filename)
+    })
+  end
+end