Read the user's preferred language from the OS (#382)

runtime/Cargo.lock

@@ -2684,6 +2684,7 @@ dependencies = [
  "serde",
  "serde_json",
  "sha2",
+ "sys-locale",
  "tauri",
  "tauri-build",
  "tauri-plugin-window-state",
@@ -4759,6 +4760,15 @@ dependencies = [
  "syn 2.0.93",
 ]
 
+[[package]]
+name = "sys-locale"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8eab9a99a024a169fe8a903cf9d4a3b3601109bcc13bd9e3c6fff259138626c4"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "system-configuration"
 version = "0.5.1"

runtime/Cargo.toml

@@ -36,6 +36,7 @@ rcgen = { version = "0.13.2", features = ["pem"] }
 file-format = "0.26.0"
 calamine = "0.26.1"
 pdfium-render = "0.8.29"
+sys-locale = "0.3.2"
 
 # Fixes security vulnerability downstream, where the upstream is not fixed yet:
 url = "2.5"

runtime/src/environment.rs

@@ -1,5 +1,6 @@
 use std::sync::OnceLock;
 use rocket::get;
+use sys_locale::get_locale;
 use crate::api_token::APIToken;
 
 /// The data directory where the application stores its data.
@@ -34,4 +35,12 @@ pub fn is_dev() -> bool {
 /// Returns true if the application is running in production mode.
 pub fn is_prod() -> bool {
     !is_dev()
+}
+
+#[get("/system/language")]
+pub fn read_user_language(_token: APIToken) -> String {
+    get_locale().unwrap_or_else(|| {
+        log::warn!("Could not determine the system language. Use default 'en-US'.");
+        String::from("en-US")
+    })
 }

runtime/src/runtime_api.rs

@@ -77,6 +77,7 @@ pub fn start_runtime_api() {
                 crate::secret::delete_secret,
                 crate::environment::get_data_directory,
                 crate::environment::get_config_directory,
+                crate::environment::read_user_language,
                 crate::file_data::extract_data,
                 crate::log::get_log_paths,
             ])