exclude replies on blocked domains

priv/repo/migrations/20200520155351_add_recipients_contain_blocked_domains_function.exs

@@ -0,0 +1,33 @@
+defmodule Pleroma.Repo.Migrations.AddRecipientsContainBlockedDomainsFunction do
+  use Ecto.Migration
+  @disable_ddl_transaction true
+
+  def up do
+    statement = """
+    CREATE OR REPLACE FUNCTION recipients_contain_blocked_domains(recipients varchar[], blocked_domains varchar[]) RETURNS boolean AS $$
+    DECLARE
+      recipient_domain varchar;
+      recipient varchar;
+    BEGIN
+      FOREACH recipient IN ARRAY recipients LOOP
+        recipient_domain = split_part(recipient, '/', 3)::varchar;
+
+        IF recipient_domain = ANY(blocked_domains) THEN
+          RETURN TRUE;
+        END IF;
+      END LOOP;
+
+      RETURN FALSE;
+    END;
+    $$ LANGUAGE plpgsql;
+    """
+
+    execute(statement)
+  end
+
+  def down do
+    execute(
+      "drop function if exists recipients_contain_blocked_domains(recipients varchar[], blocked_domains varchar[])"
+    )
+  end
+end