From 3b28803bfa91cfb0678aa1ca4733b57da0beb847 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tao=20Bror=20Bojl=C3=A9n?= <tao@btao.org>
Date: Thu, 29 Aug 2019 18:10:46 +0100
Subject: [PATCH] hide opted-out instances from federation restriction lists

---
 .../controllers/instance_controller.ex        | 31 +++++++++++++++++--
 .../lib/backend_web/views/instance_view.ex    | 17 +++++-----
 2 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/backend/lib/backend_web/controllers/instance_controller.ex b/backend/lib/backend_web/controllers/instance_controller.ex
index 40c35c9..7ad2690 100644
--- a/backend/lib/backend_web/controllers/instance_controller.ex
+++ b/backend/lib/backend_web/controllers/instance_controller.ex
@@ -1,7 +1,8 @@
 defmodule BackendWeb.InstanceController do
   use BackendWeb, :controller
-  alias Backend.Api
+  alias Backend.{Api, Instance, Repo}
   alias Graph.Cache
+  import Ecto.Query
 
   action_fallback(BackendWeb.FallbackController)
 
@@ -32,7 +33,33 @@ defmodule BackendWeb.InstanceController do
       send_resp(conn, 404, "Not found")
     else
       last_crawl = Cache.get_last_crawl(domain)
-      render(conn, "show.json", instance: instance, crawl: last_crawl)
+
+      restricted_domains =
+        instance.federation_restrictions
+        |> Enum.map(fn %{target_domain: domain} -> domain end)
+
+      opted_out_instances =
+        Instance
+        |> select([i], i.domain)
+        |> where([i], i.opt_out and i.domain in ^restricted_domains)
+        |> Repo.all()
+
+      # convert from a list of {domain, restriction_type} to a map of %{restriction_type => list_of_domains}
+      federation_restrictions =
+        instance.federation_restrictions
+        |> Enum.filter(fn %{target_domain: domain} ->
+          not Enum.member?(opted_out_instances, domain)
+        end)
+        |> Enum.reduce(%{}, fn %{target_domain: domain, type: type}, acc ->
+          Map.update(acc, type, [domain], fn curr_domains -> [domain | curr_domains] end)
+        end)
+        |> Recase.Enumerable.convert_keys(&Recase.to_camel(&1))
+
+      render(conn, "show.json",
+        instance: instance,
+        crawl: last_crawl,
+        federation_restrictions: federation_restrictions
+      )
     end
   end
 
diff --git a/backend/lib/backend_web/views/instance_view.ex b/backend/lib/backend_web/views/instance_view.ex
index 6ed8468..e79d51c 100644
--- a/backend/lib/backend_web/views/instance_view.ex
+++ b/backend/lib/backend_web/views/instance_view.ex
@@ -37,7 +37,11 @@ defmodule BackendWeb.InstanceView do
     }
   end
 
-  def render("show.json", %{instance: instance, crawl: crawl}) do
+  def render("show.json", %{
+        instance: instance,
+        crawl: crawl,
+        federation_restrictions: federation_restrictions
+      }) do
     user_threshold = get_config(:personal_instance_threshold)
 
     cond do
@@ -51,7 +55,7 @@ defmodule BackendWeb.InstanceView do
         render_domain_and_error(instance)
 
       true ->
-        render_instance(instance, crawl)
+        render_instance(instance, crawl, federation_restrictions)
     end
   end
 
@@ -73,20 +77,13 @@ defmodule BackendWeb.InstanceView do
     }
   end
 
-  defp render_instance(instance, crawl) do
+  defp render_instance(instance, crawl, federation_restrictions) do
     last_updated = max_datetime(crawl.inserted_at, instance.updated_at)
 
     filtered_peers =
       instance.peers
       |> Enum.filter(fn peer -> not peer.opt_out end)
 
-    federation_restrictions =
-      instance.federation_restrictions
-      |> Enum.reduce(%{}, fn %{target_domain: domain, type: type}, acc ->
-        Map.update(acc, type, [domain], fn curr_domains -> [domain | curr_domains] end)
-      end)
-      |> Recase.Enumerable.convert_keys(&Recase.to_camel(&1))
-
     %{
       name: instance.domain,
       description: instance.description,