From 074e675651bf098483b5ef4833f456ac127ad9a4 Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Mon, 18 Mar 2024 12:40:49 +0100
Subject: [PATCH] On registration, automatically set content languages from
 accept header

---
 Cargo.lock                         |  2 ++
 api_tests/src/user.spec.ts         | 20 +++++++++++++++++++
 crates/api_crud/src/user/create.rs | 31 +++++++++++++++++++++++-------
 3 files changed, 46 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 5ef691e26..0069d3510 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2633,6 +2633,7 @@ version = "0.19.3"
 dependencies = [
  "activitypub_federation",
  "actix-web",
+ "anyhow",
  "chrono",
  "encoding",
  "enum-map",
@@ -2645,6 +2646,7 @@ dependencies = [
  "lemmy_db_views_moderator",
  "lemmy_utils",
  "mime",
+ "moka",
  "once_cell",
  "pretty_assertions",
  "regex",
diff --git a/api_tests/src/user.spec.ts b/api_tests/src/user.spec.ts
index 4846d60f7..73f3f3942 100644
--- a/api_tests/src/user.spec.ts
+++ b/api_tests/src/user.spec.ts
@@ -139,3 +139,23 @@ test("Create user with Arabic name", async () => {
   let alphaPerson = (await resolvePerson(alpha, apShortname)).person;
   expect(alphaPerson).toBeDefined();
 });
+
+test("Create user with accept-language", async () => {
+  let lemmy_http = new LemmyHttp(alphaUrl, {
+    // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Accept-Language#syntax
+    headers: { "Accept-Language": "fr-CH, en;q=0.8, de;q=0.7, *;q=0.5" },
+  });
+  let user = await registerUser(lemmy_http, alphaUrl);
+
+  let site = await getSite(user);
+  expect(site.my_user).toBeDefined();
+  expect(site.my_user?.local_user_view.local_user.interface_language).toBe(
+    "fr",
+  );
+  let langs = site.all_languages
+    .filter(a => site.my_user?.discussion_languages.includes(a.id))
+    .map(l => l.code);
+  // should have languages from accept header, as well as "undetermined"
+  // which is automatically enabled by backend
+  expect(langs).toStrictEqual(["und", "de", "en", "fr"]);
+});
diff --git a/crates/api_crud/src/user/create.rs b/crates/api_crud/src/user/create.rs
index 29e16cb20..1c9398331 100644
--- a/crates/api_crud/src/user/create.rs
+++ b/crates/api_crud/src/user/create.rs
@@ -19,7 +19,9 @@ use lemmy_api_common::{
 use lemmy_db_schema::{
   aggregates::structs::PersonAggregates,
   source::{
+    actor_language::LocalUserLanguage,
     captcha_answer::{CaptchaAnswer, CheckCaptchaAnswer},
+    language::Language,
     local_user::{LocalUser, LocalUserInsertForm},
     local_user_vote_display_mode::LocalUserVoteDisplayMode,
     person::{Person, PersonInsertForm},
@@ -36,6 +38,7 @@ use lemmy_utils::{
     validation::is_valid_actor_name,
   },
 };
+use std::collections::HashSet;
 
 #[tracing::instrument(skip(context))]
 pub async fn register(
@@ -128,12 +131,15 @@ pub async fn register(
   let accepted_application = Some(!require_registration_application);
 
   // Get the user's preferred language using the Accept-Language header
-  let language_tag = req.headers().get("Accept-Language").and_then(|hdr| {
-    accept_language::parse(hdr.to_str().unwrap_or_default())
-      .first()
-      // Remove the optional region code
-      .map(|lang_str| lang_str.split('-').next().unwrap_or_default().to_string())
-  });
+  let language_tags: Vec<String> = req
+    .headers()
+    .get("Accept-Language")
+    .map(|hdr| accept_language::parse(hdr.to_str().unwrap_or_default()))
+    .iter()
+    .flatten()
+    // Remove the optional region code
+    .map(|lang_str| lang_str.split('-').next().unwrap_or_default().to_string())
+    .collect();
 
   // Create the local user
   let local_user_form = LocalUserInsertForm::builder()
@@ -144,13 +150,24 @@ pub async fn register(
     .accepted_application(accepted_application)
     .default_listing_type(Some(local_site.default_post_listing_type))
     .post_listing_mode(Some(local_site.default_post_listing_mode))
-    .interface_language(language_tag)
+    .interface_language(language_tags.first().cloned())
     // If its the initial site setup, they are an admin
     .admin(Some(!local_site.site_setup))
     .build();
 
   let inserted_local_user = LocalUser::create(&mut context.pool(), &local_user_form).await?;
 
+  let all_languages = Language::read_all(&mut context.pool()).await?;
+  // use hashset to avoid duplicates
+  let mut language_ids = HashSet::new();
+  for l in language_tags {
+    if let Some(found) = all_languages.iter().find(|all| all.code == l) {
+      language_ids.insert(found.id);
+    }
+  }
+  let language_ids = language_ids.into_iter().collect();
+  LocalUserLanguage::update(&mut context.pool(), language_ids, inserted_local_user.id).await?;
+
   if local_site.site_setup && require_registration_application {
     // Create the registration application
     let form = RegistrationApplicationInsertForm {