add language select widget

1 files changed, 120 insertions, 0 deletions

diff --git a/src/i18n.rs b/src/i18n.rs
new file mode 100644
index 0000000..964aaa3
--- /dev/null
+++ b/src/i18n.rs
@@ -0,0 +1,120 @@
+use std::str::FromStr;
+
+use poem::{
+    error::I18NError,
+    http::header,
+    i18n::{unic_langid::LanguageIdentifier, I18NArgs, I18NResources},
+    session::Session,
+    Endpoint, FromRequest, Middleware, Request, RequestBody,
+};
+use serde::Deserialize;
+
+#[derive(Deserialize)]
+struct Params {
+    lang: String,
+}
+
+pub async fn set_language<E: Endpoint>(next: E, mut req: Request) -> poem::Result<E::Output> {
+    if let Ok(params) = req.params::<Params>() {
+        let session = req
+            .extensions()
+            .get::<Session>()
+            .expect("To use the `set_language` middleware, the `Session` data is required.");
+        session.set("lang", params.lang);
+        println!("{:?}", session.get::<String>("lang"))
+    }
+    next.call(req).await
+}
+
+pub struct Locale(poem::i18n::I18NBundle);
+
+impl Locale {
+    /// Gets the text with arguments.
+    ///
+    /// See also: [`I18NBundle::text_with_args`](I18NBundle::text_with_args)
+    pub fn text_with_args<'a>(
+        &self,
+        id: impl AsRef<str>,
+        args: impl Into<I18NArgs<'a>>,
+    ) -> Result<String, I18NError> {
+        self.0.text_with_args(id, args)
+    }
+
+    /// Gets the text.
+    ///
+    /// See also: [`I18NBundle::text`](I18NBundle::text)
+    pub fn text(&self, id: impl AsRef<str>) -> Result<String, I18NError> {
+        self.0.text(id)
+    }
+}
+
+#[poem::async_trait]
+impl<'a> FromRequest<'a> for Locale {
+    async fn from_request(req: &'a Request, body: &mut RequestBody) -> poem::Result<Self> {
+        let session = req
+            .extensions()
+            .get::<Session>()
+            .expect("To use the `Locale` extractor, the `Session` data is required.");
+        let resources = req
+            .extensions()
+            .get::<I18NResources>()
+            .expect("To use the `Locale` extractor, the `I18NResources` data is required.");
+
+        let mut lang_id = None;
+        if let Some(lang) = session.get::<String>("lang") {
+            lang_id = Some(lang);
+        };
+
+        if let Some(lang_id) = lang_id {
+            if let Ok(lang_id) = LanguageIdentifier::from_str(&lang_id) {
+                return Ok(Self(resources.negotiate_languages(&[&lang_id])));
+            }
+        };
+
+        let accept_languages = req
+            .headers()
+            .get(header::ACCEPT_LANGUAGE)
+            .and_then(|value| value.to_str().ok())
+            .map(parse_accept_languages)
+            .unwrap_or_default();
+
+        Ok(Self(resources.negotiate_languages(&accept_languages)))
+    }
+}
+
+fn parse_accept_languages(value: &str) -> Vec<LanguageIdentifier> {
+    let mut languages = Vec::new();
+
+    for s in value.split(',').map(str::trim) {
+        if let Some(res) = parse_language(s) {
+            languages.push(res);
+        }
+    }
+
+    languages.sort_by(|(_, a), (_, b)| b.cmp(a));
+    languages
+        .into_iter()
+        .map(|(language, _)| language)
+        .collect()
+}
+
+fn parse_language(value: &str) -> Option<(LanguageIdentifier, u16)> {
+    let mut parts = value.split(';');
+    let name = parts.next()?.trim();
+    let quality = match parts.next() {
+        Some(quality) => parse_quality(quality).unwrap_or_default(),
+        None => 1000,
+    };
+    let language = LanguageIdentifier::from_str(name).ok()?;
+    Some((language, quality))
+}
+
+fn parse_quality(value: &str) -> Option<u16> {
+    let mut parts = value.split('=');
+    let name = parts.next()?.trim();
+    if name != "q" {
+        return None;
+    }
+    let q = parts.next()?.trim().parse::<f32>().ok()?;
+    Some((q.clamp(0.0, 1.0) * 1000.0) as u16)
+}