[#477] User: FTS and trigram search results mixing (to handle misspelled requests).

lib/pleroma/user.ex

@@ -679,13 +679,35 @@ def get_recipients_from_activity(%Activity{recipients: to}) do
   end
 
   def search(query, resolve \\ false, for_user \\ nil) do
-    # strip the beginning @ off if there is a query
+    # Strip the beginning @ off if there is a query
     query = String.trim_leading(query, "@")
 
-    if resolve do
+    if resolve, do: User.get_or_fetch_by_nickname(query)
-      User.get_or_fetch_by_nickname(query)
+
+    fts_results = do_search(fts_search_subquery(query), for_user)
+
+    trigram_results = do_search(trigram_search_subquery(query), for_user)
+
+    Enum.uniq_by(fts_results ++ trigram_results, & &1.id)
   end
 
+  defp do_search(subquery, for_user, options \\ []) do
+    q =
+      from(
+        s in subquery(subquery),
+        order_by: [desc: s.search_rank],
+        limit: ^(options[:limit] || 20)
+      )
+
+    results =
+      q
+      |> Repo.all()
+      |> Enum.filter(&(&1.search_rank > 0))
+
+    boost_search_results(results, for_user)
+  end
+
+  defp fts_search_subquery(query) do
     processed_query =
       query
       |> String.replace(~r/\W+/, " ")
@@ -694,7 +716,6 @@ def search(query, resolve \\ false, for_user \\ nil) do
       |> Enum.map(&(&1 <> ":*"))
       |> Enum.join(" | ")
 
-    inner =
     from(
       u in User,
       select_merge: %{
@@ -715,21 +736,27 @@ def search(query, resolve \\ false, for_user \\ nil) do
       },
       where: not is_nil(u.nickname)
     )
+  end
 
-    q =
+  defp trigram_search_subquery(query) do
     from(
-        s in subquery(inner),
+      u in User,
-        order_by: [desc: s.search_rank],
+      select_merge: %{
-        limit: 20
+        search_rank:
+          fragment(
+            "similarity(?, ? || ' ' || coalesce(?, ''))",
+            ^query,
+            u.nickname,
+            u.name
           )
+      },
+      where: not is_nil(u.nickname)
+    )
+  end
 
-    results =
+  defp boost_search_results(results, nil), do: results
-      q
-      |> Repo.all()
-      |> Enum.filter(&(&1.search_rank > 0))
 
-    weighted_results =
+  defp boost_search_results(results, for_user) do
-      if for_user do
     friends_ids = get_friends_ids(for_user)
     followers_ids = get_followers_ids(for_user)
 
@@ -752,11 +779,6 @@ def search(query, resolve \\ false, for_user \\ nil) do
       end
     )
     |> Enum.sort_by(&(-&1.search_rank))
-      else
-        results
-      end
-
-    weighted_results
   end
 
   def blocks_import(%User{} = blocker, blocked_identifiers) when is_list(blocked_identifiers) do

test/user_test.exs

@@ -814,6 +814,12 @@ test "finds users, ranking by similarity" do
       assert [u4.id, u3.id, u1.id] == Enum.map(User.search("lain@ple"), & &1.id)
     end
 
+    test "finds users, handling misspelled requests" do
+      u1 = insert(:user, %{name: "lain"})
+
+      assert [u1.id] == Enum.map(User.search("laiin"), & &1.id)
+    end
+
     test "finds users, boosting ranks of friends and followers" do
       u1 = insert(:user)
       u2 = insert(:user, %{name: "Doe"})

test/web/twitter_api/twitter_api_controller_test.exs

@@ -1656,7 +1656,7 @@ test "it denies a friend request" do
     test "it returns users, ordered by similarity", %{conn: conn} do
       user = insert(:user, %{name: "eal"})
       user_two = insert(:user, %{name: "eal me"})
-      _user_three = insert(:user, %{name: "ebn"})
+      _user_three = insert(:user, %{name: "zzz"})
 
       resp =
         conn