ConfigDB, RateLimiter, RateLimit: Use new type to parse and cast rate limits.

lib/pleroma/config_db.ex

@@ -10,6 +10,7 @@ defmodule Pleroma.ConfigDB do
   import Pleroma.Web.Gettext
 
   alias __MODULE__
+  alias Pleroma.EctoType.Config.RateLimit
   alias Pleroma.Repo
 
   @type t :: %__MODULE__{}
@@ -60,8 +61,59 @@ defmodule Pleroma.ConfigDB do
     |> cast(params, [:key, :group, :value])
     |> validate_required([:key, :group, :value])
     |> unique_constraint(:key, name: :config_group_key_index)
+    |> validate_rate_limit()
   end
 
+  defp validate_rate_limit(changeset) do
+    group = get_field(changeset, :group)
+    key = get_field(changeset, :key)
+
+    if group == :pleroma and key == :rate_limit do
+      value = get_field(changeset, :value)
+
+      case normalize_rate_limit(value) do
+        {:ok, normalized_value} ->
+          put_change(changeset, :value, normalized_value)
+
+        {:error, {limiter_name, reason}} ->
+          add_error(
+            changeset,
+            :value,
+            "invalid :rate_limit value for #{inspect(limiter_name)}: #{reason}"
+          )
+      end
+    else
+      changeset
+    end
+  end
+
+  defp normalize_rate_limit(nil), do: {:ok, nil}
+
+  defp normalize_rate_limit(%{} = value), do: normalize_rate_limit(Map.to_list(value))
+
+  defp normalize_rate_limit(value) when is_list(value) do
+    if Keyword.keyword?(value) do
+      value
+      |> Enum.reduce_while({:ok, []}, fn {limiter_name, limiter_value}, {:ok, acc} ->
+        case RateLimit.cast_with_error(limiter_value) do
+          {:ok, normalized_limiter_value} ->
+            {:cont, {:ok, [{limiter_name, normalized_limiter_value} | acc]}}
+
+          {:error, reason} ->
+            {:halt, {:error, {limiter_name, reason}}}
+        end
+      end)
+      |> case do
+        {:ok, acc} -> {:ok, Enum.reverse(acc)}
+        {:error, _} = error -> error
+      end
+    else
+      {:error, {:rate_limit, "must be a keyword list"}}
+    end
+  end
+
+  defp normalize_rate_limit(_), do: {:error, {:rate_limit, "must be a keyword list"}}
+
   defp create(params) do
     %ConfigDB{}
     |> changeset(params)

lib/pleroma/ecto_type/config/rate_limit.ex

@@ -0,0 +1,71 @@
+# Pleroma: A lightweight social networking server
+# Copyright © Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.EctoType.Config.RateLimit do
+  @moduledoc false
+
+  use Ecto.Type
+
+  @type t ::
+          nil
+          | {non_neg_integer(), non_neg_integer()}
+          | [{non_neg_integer(), non_neg_integer()}]
+
+  @impl true
+  def type, do: :term
+
+  @impl true
+  def cast(value) do
+    case cast_with_error(value) do
+      {:ok, normalized} -> {:ok, normalized}
+      {:error, _reason} -> :error
+    end
+  end
+
+  @impl true
+  def load(value), do: cast(value)
+
+  @impl true
+  def dump(value), do: cast(value)
+
+  @spec cast_with_error(term()) :: {:ok, t()} | {:error, String.t()}
+  def cast_with_error(nil), do: {:ok, nil}
+
+  def cast_with_error({scale, limit}) do
+    with {:ok, scale} <- parse_integer(scale, "scale"),
+         {:ok, limit} <- parse_integer(limit, "limit"),
+         true <- scale >= 1 and limit >= 1 do
+      {:ok, {scale, limit}}
+    else
+      false -> {:error, "scale and limit must be >= 1"}
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
+  def cast_with_error([{_, _} = unauth, {_, _} = auth]) do
+    with {:ok, unauth} <- cast_with_error(unauth),
+         {:ok, auth} <- cast_with_error(auth) do
+      {:ok, [unauth, auth]}
+    else
+      {:error, reason} -> {:error, reason}
+    end
+  end
+
+  def cast_with_error(_),
+    do:
+      {:error, "must be a {scale, limit} tuple, a [{scale, limit}, {scale, limit}] list, or nil"}
+
+  defp parse_integer(value, _label) when is_integer(value), do: {:ok, value}
+
+  defp parse_integer(value, label) when is_binary(value) do
+    value = String.trim(value)
+
+    case Integer.parse(value) do
+      {number, ""} -> {:ok, number}
+      _ -> {:error, "#{label} must be an integer"}
+    end
+  end
+
+  defp parse_integer(_value, label), do: {:error, "#{label} must be an integer"}
+end

lib/pleroma/web/plugs/rate_limiter.ex

@@ -68,6 +68,7 @@ defmodule Pleroma.Web.Plugs.RateLimiter do
 
   alias Pleroma.Config
   alias Pleroma.Config.Holder
+  alias Pleroma.EctoType.Config.RateLimit
   alias Pleroma.User
   alias Pleroma.Web.Plugs.RateLimiter.LimiterSupervisor
 
@@ -214,40 +215,13 @@ defmodule Pleroma.Web.Plugs.RateLimiter do
 
   defp normalize_limits(nil), do: :disabled
 
-  defp normalize_limits({scale, limit}) do
-    with {:ok, scale} <- normalize_integer(scale),
-         {:ok, limit} <- normalize_integer(limit),
-         true <- scale >= 1 and limit >= 1 do
-      {:ok, {scale, limit}}
-    else
-      _ -> :error
+  defp normalize_limits(limits) do
+    case RateLimit.cast(limits) do
+      {:ok, normalized_limits} -> {:ok, normalized_limits}
+      :error -> :error
     end
   end
 
-  defp normalize_limits([{_, _} = first, {_, _} = second]) do
-    with {:ok, first} <- normalize_limits(first),
-         {:ok, second} <- normalize_limits(second) do
-      {:ok, [first, second]}
-    else
-      _ -> :error
-    end
-  end
-
-  defp normalize_limits(_), do: :error
-
-  defp normalize_integer(value) when is_integer(value), do: {:ok, value}
-
-  defp normalize_integer(value) when is_binary(value) do
-    value = String.trim(value)
-
-    case Integer.parse(value) do
-      {number, ""} -> {:ok, number}
-      _ -> :error
-    end
-  end
-
-  defp normalize_integer(_), do: :error
-
   defp check_rate(action_settings) do
     bucket_name = make_bucket_name(action_settings)
     key_name = make_key_name(action_settings)