From 97253df3ee0b38256ac19ebfafebbc69b162b14c Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 10 Sep 2018 00:53:37 +0000
Subject: [PATCH 1/3] MRF: simple policy: contain media removal/nsfw ops to
 create activities only

---
 lib/pleroma/web/activity_pub/mrf/simple_policy.ex | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
index 7fecb8a4f..49caef5b2 100644
--- a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
@@ -23,7 +23,8 @@ defp check_reject(actor_info, object) do
   end
 
   @media_removal Keyword.get(@mrf_policy, :media_removal)
-  defp check_media_removal(actor_info, object) do
+  defp check_media_removal(actor_info, %{"type" => activity_type} = object)
+       when activity_type == "Create" do
     if actor_info.host in @media_removal do
       child_object = Map.delete(object["object"], "attachment")
       object = Map.put(object, "object", child_object)
@@ -33,8 +34,11 @@ defp check_media_removal(actor_info, object) do
     end
   end
 
+  defp check_media_removal(actor_info, object), do: {:ok, object}
+
   @media_nsfw Keyword.get(@mrf_policy, :media_nsfw)
-  defp check_media_nsfw(actor_info, object) do
+  defp check_media_nsfw(actor_info, %{"type" => activity_type} = object)
+       when activity_type == "Create" do
     child_object = object["object"]
 
     if actor_info.host in @media_nsfw and child_object["attachment"] != nil and
@@ -49,6 +53,8 @@ defp check_media_nsfw(actor_info, object) do
     end
   end
 
+  defp check_media_nsfw(actor_info, object), do: {:ok, object}
+
   @ftl_removal Keyword.get(@mrf_policy, :federated_timeline_removal)
   defp check_ftl_removal(actor_info, object) do
     if actor_info.host in @ftl_removal do

From 88094c266d74acccc6efa304dc0bd85638849a87 Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 10 Sep 2018 01:06:44 +0000
Subject: [PATCH 2/3] MRF: simple policy: refactor module to use guards and
 pattern matching

---
 .../web/activity_pub/mrf/simple_policy.ex     | 107 ++++++++----------
 1 file changed, 49 insertions(+), 58 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
index 49caef5b2..319721d48 100644
--- a/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
+++ b/lib/pleroma/web/activity_pub/mrf/simple_policy.ex
@@ -5,86 +5,77 @@ defmodule Pleroma.Web.ActivityPub.MRF.SimplePolicy do
   @mrf_policy Application.get_env(:pleroma, :mrf_simple)
 
   @accept Keyword.get(@mrf_policy, :accept)
-  defp check_accept(actor_info, object) do
-    if length(@accept) > 0 and not (actor_info.host in @accept) do
-      {:reject, nil}
-    else
-      {:ok, object}
-    end
+  defp check_accept(%{host: actor_host} = actor_info, object)
+       when length(@accept) > 0 and not (actor_host in @accept) do
+    {:reject, nil}
   end
 
+  defp check_accept(actor_info, object), do: {:ok, object}
+
   @reject Keyword.get(@mrf_policy, :reject)
-  defp check_reject(actor_info, object) do
-    if actor_info.host in @reject do
-      {:reject, nil}
-    else
-      {:ok, object}
-    end
+  defp check_reject(%{host: actor_host} = actor_info, object) when actor_host in @reject do
+    {:reject, nil}
   end
 
+  defp check_reject(actor_info, object), do: {:ok, object}
+
   @media_removal Keyword.get(@mrf_policy, :media_removal)
-  defp check_media_removal(actor_info, %{"type" => activity_type} = object)
-       when activity_type == "Create" do
-    if actor_info.host in @media_removal do
-      child_object = Map.delete(object["object"], "attachment")
-      object = Map.put(object, "object", child_object)
-      {:ok, object}
-    else
-      {:ok, object}
-    end
+  defp check_media_removal(%{host: actor_host} = actor_info, %{"type" => "Create"} = object)
+       when actor_host in @media_removal do
+    child_object = Map.delete(object["object"], "attachment")
+    object = Map.put(object, "object", child_object)
+    {:ok, object}
   end
 
   defp check_media_removal(actor_info, object), do: {:ok, object}
 
   @media_nsfw Keyword.get(@mrf_policy, :media_nsfw)
-  defp check_media_nsfw(actor_info, %{"type" => activity_type} = object)
-       when activity_type == "Create" do
-    child_object = object["object"]
-
-    if actor_info.host in @media_nsfw and child_object["attachment"] != nil and
-         length(child_object["attachment"]) > 0 do
-      tags = (child_object["tag"] || []) ++ ["nsfw"]
-      child_object = Map.put(child_object, "tags", tags)
-      child_object = Map.put(child_object, "sensitive", true)
-      object = Map.put(object, "object", child_object)
-      {:ok, object}
-    else
-      {:ok, object}
-    end
+  defp check_media_nsfw(
+         %{host: actor_host} = actor_info,
+         %{
+           "type" => "Create",
+           "object" => %{"attachment" => child_attachment} = child_object
+         } = object
+       )
+       when actor_host in @media_nsfw and length(child_attachment) > 0 do
+    tags = (child_object["tag"] || []) ++ ["nsfw"]
+    child_object = Map.put(child_object, "tags", tags)
+    child_object = Map.put(child_object, "sensitive", true)
+    object = Map.put(object, "object", child_object)
+    {:ok, object}
   end
 
   defp check_media_nsfw(actor_info, object), do: {:ok, object}
 
   @ftl_removal Keyword.get(@mrf_policy, :federated_timeline_removal)
-  defp check_ftl_removal(actor_info, object) do
-    if actor_info.host in @ftl_removal do
-      user = User.get_by_ap_id(object["actor"])
+  defp check_ftl_removal(%{host: actor_host} = actor_info, object)
+       when actor_host in @ftl_removal do
+    user = User.get_by_ap_id(object["actor"])
 
-      # flip to/cc relationship to make the post unlisted
-      object =
-        if "https://www.w3.org/ns/activitystreams#Public" in object["to"] and
-             user.follower_address in object["cc"] do
-          to =
-            List.delete(object["to"], "https://www.w3.org/ns/activitystreams#Public") ++
-              [user.follower_address]
+    # flip to/cc relationship to make the post unlisted
+    object =
+      if "https://www.w3.org/ns/activitystreams#Public" in object["to"] and
+           user.follower_address in object["cc"] do
+        to =
+          List.delete(object["to"], "https://www.w3.org/ns/activitystreams#Public") ++
+            [user.follower_address]
 
-          cc =
-            List.delete(object["cc"], user.follower_address) ++
-              ["https://www.w3.org/ns/activitystreams#Public"]
+        cc =
+          List.delete(object["cc"], user.follower_address) ++
+            ["https://www.w3.org/ns/activitystreams#Public"]
 
-          object
-          |> Map.put("to", to)
-          |> Map.put("cc", cc)
-        else
-          object
-        end
+        object
+        |> Map.put("to", to)
+        |> Map.put("cc", cc)
+      else
+        object
+      end
 
-      {:ok, object}
-    else
-      {:ok, object}
-    end
+    {:ok, object}
   end
 
+  defp check_ftl_removal(actor_info, object), do: {:ok, object}
+
   @impl true
   def filter(object) do
     actor_info = URI.parse(object["actor"])

From e0b8c0ccba57cb8f920929c61b64c523f431edec Mon Sep 17 00:00:00 2001
From: William Pitcock <nenolod@dereferenced.org>
Date: Mon, 10 Sep 2018 01:13:38 +0000
Subject: [PATCH 3/3] MRF: reject non-public: use pattern match to remove
 unnecessary if block

---
 .../web/activity_pub/mrf/reject_non_public.ex | 65 +++++++++----------
 1 file changed, 32 insertions(+), 33 deletions(-)

diff --git a/lib/pleroma/web/activity_pub/mrf/reject_non_public.ex b/lib/pleroma/web/activity_pub/mrf/reject_non_public.ex
index b6936fe90..129d04617 100644
--- a/lib/pleroma/web/activity_pub/mrf/reject_non_public.ex
+++ b/lib/pleroma/web/activity_pub/mrf/reject_non_public.ex
@@ -7,43 +7,42 @@ defmodule Pleroma.Web.ActivityPub.MRF.RejectNonPublic do
   @allow_direct Keyword.get(@mrf_rejectnonpublic, :allow_direct)
 
   @impl true
-  def filter(object) do
-    if object["type"] == "Create" do
-      user = User.get_cached_by_ap_id(object["actor"])
-      public = "https://www.w3.org/ns/activitystreams#Public"
+  def filter(%{"type" => "Create"} = object) do
+    user = User.get_cached_by_ap_id(object["actor"])
+    public = "https://www.w3.org/ns/activitystreams#Public"
 
-      # Determine visibility
-      visibility =
-        cond do
-          public in object["to"] -> "public"
-          public in object["cc"] -> "unlisted"
-          user.follower_address in object["to"] -> "followers"
-          true -> "direct"
+    # Determine visibility
+    visibility =
+      cond do
+        public in object["to"] -> "public"
+        public in object["cc"] -> "unlisted"
+        user.follower_address in object["to"] -> "followers"
+        true -> "direct"
+      end
+
+    case visibility do
+      "public" ->
+        {:ok, object}
+
+      "unlisted" ->
+        {:ok, object}
+
+      "followers" ->
+        with true <- @allow_followersonly do
+          {:ok, object}
+        else
+          _e -> {:reject, nil}
         end
 
-      case visibility do
-        "public" ->
+      "direct" ->
+        with true <- @allow_direct do
           {:ok, object}
-
-        "unlisted" ->
-          {:ok, object}
-
-        "followers" ->
-          with true <- @allow_followersonly do
-            {:ok, object}
-          else
-            _e -> {:reject, nil}
-          end
-
-        "direct" ->
-          with true <- @allow_direct do
-            {:ok, object}
-          else
-            _e -> {:reject, nil}
-          end
-      end
-    else
-      {:ok, object}
+        else
+          _e -> {:reject, nil}
+        end
     end
   end
+
+  @impl true
+  def filter(object), do: {:ok, object}
 end