3 files changed, 22 insertions, 1 deletions
diff --git a/lib/pleroma/web/common_api/activity_draft.ex b/lib/pleroma/web/common_api/activity_draft.ex
index b4e3e37ae..451d7323a 100644
--- a/lib/pleroma/web/common_api/activity_draft.ex
+++ b/lib/pleroma/web/common_api/activity_draft.ex
@@ -112,7 +112,12 @@ defmodule Pleroma.Web.CommonAPI.ActivityDraft do
 
   defp attachments(%{params: params} = draft) do
     attachments = Utils.attachments_from_ids(params)
-    %__MODULE__{draft | attachments: attachments}
+    draft = %__MODULE__{draft | attachments: attachments}
+
+    case Utils.validate_attachments_count(attachments) do
+      :ok -> draft
+      {:error, message} -> add_error(draft, message)
+    end
   end
 
   defp in_reply_to(%{params: %{in_reply_to_status_id: ""}} = draft), do: draft
diff --git a/lib/pleroma/web/common_api/utils.ex b/lib/pleroma/web/common_api/utils.ex
index b6feaf32a..5bba01cc4 100644
--- a/lib/pleroma/web/common_api/utils.ex
+++ b/lib/pleroma/web/common_api/utils.ex
@@ -492,4 +492,19 @@ defmodule Pleroma.Web.CommonAPI.Utils do
       {:error, dgettext("errors", "The status is over the character limit")}
     end
   end
+
+  def validate_attachments_count([] = _attachments) do
+    :ok
+  end
+
+  def validate_attachments_count(attachments) do
+    limit = Config.get([:instance, :max_media_attachments])
+    count = length(attachments)
+
+    if count <= limit do
+      :ok
+    else
+      {:error, dgettext("errors", "Too many attachments")}
+    end
+  end
 end
diff --git a/lib/pleroma/web/mastodon_api/views/instance_view.ex b/lib/pleroma/web/mastodon_api/views/instance_view.ex
index fa6c20a30..23770f671 100644
--- a/lib/pleroma/web/mastodon_api/views/instance_view.ex
+++ b/lib/pleroma/web/mastodon_api/views/instance_view.ex
@@ -31,6 +31,7 @@ defmodule Pleroma.Web.MastodonAPI.InstanceView do
       approval_required: Keyword.get(instance, :account_approval_required),
       # Extra (not present in Mastodon):
       max_toot_chars: Keyword.get(instance, :limit),
+      max_media_attachments: Keyword.get(instance, :max_media_attachments),
       poll_limits: Keyword.get(instance, :poll_limits),
       upload_limit: Keyword.get(instance, :upload_limit),
       avatar_upload_limit: Keyword.get(instance, :avatar_upload_limit),