tide_etag/
lib.rs

1use lz_fnv::{Fnv1a, FnvHasher};
2use tide::{Body, Request};
3
4pub struct EtagMiddleware {}
5
6impl Default for EtagMiddleware {
7    /// Create a default etag middleware
8    ///
9    /// # Examples
10    ///
11    /// ```no_run
12    ///
13    /// let mut app = tide::new();
14    /// app.with(tide_etag::EtagMiddleware::default());
15    ///
16    /// app.at("/").get(|_| async {
17    ///     let mut resp = tide::Response::new(200);
18    ///     resp.set_body(tide::Body::from_string("HELLO".to_string()));
19    ///     Ok(resp)
20    /// });
21    /// app.listen("127.0.0.1:8080").await?;
22    /// ```
23    fn default() -> Self {
24        Self {}
25    }
26}
27
28#[tide::utils::async_trait]
29impl<State: Clone + Send + Sync + 'static> tide::Middleware<State> for EtagMiddleware {
30    async fn handle(&self, req: Request<State>, next: tide::Next<'_, State>) -> tide::Result {
31        let if_none_match = req.header(tide::http::headers::IF_NONE_MATCH).cloned();
32        let mut response = next.run(req).await;
33        if let Some(existing_etag) = response.header(tide::http::headers::ETAG) {
34            if let Some(req_hash) = if_none_match {
35                if req_hash.last().as_str() == existing_etag.last().as_str() {
36                    response.set_status(304);
37                    response.take_body();
38                    return Ok(response);
39                }
40            }
41            return Ok(response);
42        }
43        let body = response.take_body();
44        let mut hasher = Fnv1a::<u32>::new();
45        let bytes = &body.into_bytes().await?;
46        hasher.write(&bytes);
47        let hash = hasher.finish();
48        let generated_etag = base64::encode(hash.to_be_bytes());
49        response.append_header(tide::http::headers::ETAG, &generated_etag);
50        if let Some(req_hash) = if_none_match {
51            if req_hash.last().as_str() == generated_etag {
52                response.set_status(304);
53                return Ok(response);
54            }
55        }
56        response.set_body(Body::from_bytes(bytes.to_vec()));
57        Ok(response)
58    }
59}
tide_etag/lib.rs

tide_etag/
lib.rs
