Improve OpenAPI errors

lib/pleroma/web/api_spec/render_error.ex

@@ -5,23 +5,227 @@
 defmodule Pleroma.Web.ApiSpec.RenderError do
   @behaviour Plug
 
-  alias OpenApiSpex.Plug.JsonRenderError
-  alias Plug.Conn
+  import Plug.Conn, only: [put_status: 2]
+  import Phoenix.Controller, only: [json: 2]
+  import Pleroma.Web.Gettext
 
   @impl Plug
   def init(opts), do: opts
 
   @impl Plug
 
-  def call(%{private: %{open_api_spex: %{operation_id: "AccountController.create"}}} = conn, _) do
+  def call(conn, errors) do
+    errors =
+      Enum.map(errors, fn
+        %{name: nil} = err ->
+          %OpenApiSpex.Cast.Error{err | name: List.last(err.path)}
+
+        err ->
+          err
+      end)
+
     conn
-    |> Conn.put_status(:bad_request)
-    |> Phoenix.Controller.json(%{"error" => "Missing parameters"})
+    |> put_status(:bad_request)
+    |> json(%{
+      error: errors |> Enum.map(&message/1) |> Enum.join(" "),
+      errors: errors |> Enum.map(&render_error/1)
+    })
   end
 
-  def call(conn, reason) do
-    opts = JsonRenderError.init(reason)
+  defp render_error(error) do
+    pointer = OpenApiSpex.path_to_string(error)
 
-    JsonRenderError.call(conn, opts)
+    %{
+      title: "Invalid value",
+      source: %{
+        pointer: pointer
+      },
+      message: OpenApiSpex.Cast.Error.message(error)
+    }
+  end
+
+  defp message(%{reason: :invalid_schema_type, type: type, name: name}) do
+    gettext("%{name} - Invalid schema.type. Got: %{type}.",
+      name: name,
+      type: inspect(type)
+    )
+  end
+
+  defp message(%{reason: :null_value, name: name} = error) do
+    case error.type do
+      nil ->
+        gettext("%{name} - null value.", name: name)
+
+      type ->
+        gettext("%{name} - null value where %{type} expected.",
+          name: name,
+          type: type
+        )
+    end
+  end
+
+  defp message(%{reason: :all_of, meta: %{invalid_schema: invalid_schema}}) do
+    gettext(
+      "Failed to cast value as %{invalid_schema}. Value must be castable using `allOf` schemas listed.",
+      invalid_schema: invalid_schema
+    )
+  end
+
+  defp message(%{reason: :any_of, meta: %{failed_schemas: failed_schemas}}) do
+    gettext("Failed to cast value using any of: %{failed_schemas}.",
+      failed_schemas: failed_schemas
+    )
+  end
+
+  defp message(%{reason: :one_of, meta: %{failed_schemas: failed_schemas}}) do
+    gettext("Failed to cast value to one of: %{failed_schemas}.", failed_schemas: failed_schemas)
+  end
+
+  defp message(%{reason: :min_length, length: length, name: name}) do
+    gettext("%{name} - String length is smaller than minLength: %{length}.",
+      name: name,
+      length: length
+    )
+  end
+
+  defp message(%{reason: :max_length, length: length, name: name}) do
+    gettext("%{name} - String length is larger than maxLength: %{length}.",
+      name: name,
+      length: length
+    )
+  end
+
+  defp message(%{reason: :unique_items, name: name}) do
+    gettext("%{name} - Array items must be unique.", name: name)
+  end
+
+  defp message(%{reason: :min_items, length: min, value: array, name: name}) do
+    gettext("%{name} - Array length %{length} is smaller than minItems: %{min}.",
+      name: name,
+      length: length(array),
+      min: min
+    )
+  end
+
+  defp message(%{reason: :max_items, length: max, value: array, name: name}) do
+    gettext("%{name} - Array length %{length} is larger than maxItems: %{}.",
+      name: name,
+      length: length(array),
+      max: max
+    )
+  end
+
+  defp message(%{reason: :multiple_of, length: multiple, value: count, name: name}) do
+    gettext("%{name} - %{count} is not a multiple of %{multiple}.",
+      name: name,
+      count: count,
+      multiple: multiple
+    )
+  end
+
+  defp message(%{reason: :exclusive_max, length: max, value: value, name: name})
+       when value >= max do
+    gettext("%{name} - %{value} is larger than exclusive maximum %{max}.",
+      name: name,
+      value: value,
+      max: max
+    )
+  end
+
+  defp message(%{reason: :maximum, length: max, value: value, name: name})
+       when value > max do
+    gettext("%{name} - %{value} is larger than inclusive maximum %{max}.",
+      name: name,
+      value: value,
+      max: max
+    )
+  end
+
+  defp message(%{reason: :exclusive_multiple, length: min, value: value, name: name})
+       when value <= min do
+    gettext("%{name} - %{value} is smaller than exclusive minimum %{min}.",
+      name: name,
+      value: value,
+      min: min
+    )
+  end
+
+  defp message(%{reason: :minimum, length: min, value: value, name: name})
+       when value < min do
+    gettext("%{name} - %{value} is smaller than inclusive minimum %{min}.",
+      name: name,
+      value: value,
+      min: min
+    )
+  end
+
+  defp message(%{reason: :invalid_type, type: type, value: value, name: name}) do
+    gettext("%{name} - Invalid %{type}. Got: %{value}.",
+      name: name,
+      value: OpenApiSpex.TermType.type(value),
+      type: type
+    )
+  end
+
+  defp message(%{reason: :invalid_format, format: format, name: name}) do
+    gettext("%{name} - Invalid format. Expected %{format}.", name: name, format: inspect(format))
+  end
+
+  defp message(%{reason: :invalid_enum, name: name}) do
+    gettext("%{name} - Invalid value for enum.", name: name)
+  end
+
+  defp message(%{reason: :polymorphic_failed, type: polymorphic_type}) do
+    gettext("Failed to cast to any schema in %{polymorphic_type}",
+      polymorphic_type: polymorphic_type
+    )
+  end
+
+  defp message(%{reason: :unexpected_field, name: name}) do
+    gettext("Unexpected field: %{name}.", name: safe_string(name))
+  end
+
+  defp message(%{reason: :no_value_for_discriminator, name: field}) do
+    gettext("Value used as discriminator for `%{field}` matches no schemas.", name: field)
+  end
+
+  defp message(%{reason: :invalid_discriminator_value, name: field}) do
+    gettext("No value provided for required discriminator `%{field}`.", name: field)
+  end
+
+  defp message(%{reason: :unknown_schema, name: name}) do
+    gettext("Unknown schema: %{name}.", name: name)
+  end
+
+  defp message(%{reason: :missing_field, name: name}) do
+    gettext("Missing field: %{name}.", name: name)
+  end
+
+  defp message(%{reason: :missing_header, name: name}) do
+    gettext("Missing header: %{name}.", name: name)
+  end
+
+  defp message(%{reason: :invalid_header, name: name}) do
+    gettext("Invalid value for header: %{name}.", name: name)
+  end
+
+  defp message(%{reason: :max_properties, meta: meta}) do
+    gettext(
+      "Object property count %{property_count} is greater than maxProperties: %{max_properties}.",
+      property_count: meta.property_count,
+      max_properties: meta.max_properties
+    )
+  end
+
+  defp message(%{reason: :min_properties, meta: meta}) do
+    gettext(
+      "Object property count %{property_count} is less than minProperties: %{min_properties}",
+      property_count: meta.property_count,
+      min_properties: meta.min_properties
+    )
+  end
+
+  defp safe_string(string) do
+    to_string(string) |> String.slice(0..39)
   end
 end

test/web/mastodon_api/controllers/account_controller_test.exs

@@ -952,7 +952,16 @@ test "returns bad_request if missing required params", %{
           |> post("/api/v1/accounts", Map.delete(valid_params, attr))
           |> json_response(400)
 
-        assert res == %{"error" => "Missing parameters"}
+        assert res == %{
+                 "error" => "Missing field: #{attr}.",
+                 "errors" => [
+                   %{
+                     "message" => "Missing field: #{attr}",
+                     "source" => %{"pointer" => "/#{attr}"},
+                     "title" => "Invalid value"
+                   }
+                 ]
+               }
       end)
     end