mas_handlers/
preferred_language.rs

1// Copyright 2024, 2025 New Vector Ltd.
2// Copyright 2023, 2024 The Matrix.org Foundation C.I.C.
3//
4// SPDX-License-Identifier: AGPL-3.0-only
5// Please see LICENSE in the repository root for full details.
6
7use std::{convert::Infallible, sync::Arc};
8
9use axum::{
10    extract::{FromRef, FromRequestParts},
11    http::request::Parts,
12};
13use headers::HeaderMapExt as _;
14use mas_axum_utils::language_detection::AcceptLanguage;
15use mas_i18n::{DataLocale, Translator, locale};
16
17pub struct PreferredLanguage(pub DataLocale);
18
19impl<S> FromRequestParts<S> for PreferredLanguage
20where
21    S: Send + Sync,
22    Arc<Translator>: FromRef<S>,
23{
24    type Rejection = Infallible;
25
26    async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
27        let translator: Arc<Translator> = FromRef::from_ref(state);
28        let accept_language = parts.headers.typed_get::<AcceptLanguage>();
29
30        let iter = accept_language
31            .iter()
32            .flat_map(AcceptLanguage::iter)
33            .flat_map(|lang| {
34                let lang = DataLocale::from(lang);
35                // XXX: this is hacky as we may want to actually maintain proper language
36                // aliases at some point, but `zh-CN` doesn't fallback
37                // automatically to `zh-Hans`, so we insert it manually here.
38                // For some reason, `zh-TW` does fallback to `zh-Hant` correctly.
39                if lang == locale!("zh-CN").into() {
40                    vec![lang, locale!("zh-Hans").into()]
41                } else {
42                    vec![lang]
43                }
44            });
45
46        let locale = translator.choose_locale(iter);
47
48        Ok(PreferredLanguage(locale))
49    }
50}
mas_handlers/preferred_language.rs

mas_handlers/
preferred_language.rs
