tower_http/compression/
layer.rs

1use super::{Compression, Predicate};
2use crate::compression::predicate::DefaultPredicate;
3use crate::compression::CompressionLevel;
4use crate::compression_utils::AcceptEncoding;
5use tower_layer::Layer;
6
7/// Compress response bodies of the underlying service.
8///
9/// This uses the `Accept-Encoding` header to pick an appropriate encoding and adds the
10/// `Content-Encoding` header to responses.
11///
12/// See the [module docs](crate::compression) for more details.
13#[derive(Clone, Debug, Default)]
14pub struct CompressionLayer<P = DefaultPredicate> {
15    accept: AcceptEncoding,
16    predicate: P,
17    quality: CompressionLevel,
18}
19
20impl<S, P> Layer<S> for CompressionLayer<P>
21where
22    P: Predicate,
23{
24    type Service = Compression<S, P>;
25
26    fn layer(&self, inner: S) -> Self::Service {
27        Compression {
28            inner,
29            accept: self.accept,
30            predicate: self.predicate.clone(),
31            quality: self.quality,
32        }
33    }
34}
35
36impl CompressionLayer {
37    /// Creates a new [`CompressionLayer`].
38    pub fn new() -> Self {
39        Self::default()
40    }
41
42    /// Sets whether to enable the gzip encoding.
43    #[cfg(feature = "compression-gzip")]
44    pub fn gzip(mut self, enable: bool) -> Self {
45        self.accept.set_gzip(enable);
46        self
47    }
48
49    /// Sets whether to enable the Deflate encoding.
50    #[cfg(feature = "compression-deflate")]
51    pub fn deflate(mut self, enable: bool) -> Self {
52        self.accept.set_deflate(enable);
53        self
54    }
55
56    /// Sets whether to enable the Brotli encoding.
57    #[cfg(feature = "compression-br")]
58    pub fn br(mut self, enable: bool) -> Self {
59        self.accept.set_br(enable);
60        self
61    }
62
63    /// Sets whether to enable the Zstd encoding.
64    #[cfg(feature = "compression-zstd")]
65    pub fn zstd(mut self, enable: bool) -> Self {
66        self.accept.set_zstd(enable);
67        self
68    }
69
70    /// Sets the compression quality.
71    pub fn quality(mut self, quality: CompressionLevel) -> Self {
72        self.quality = quality;
73        self
74    }
75
76    /// Disables the gzip encoding.
77    ///
78    /// This method is available even if the `gzip` crate feature is disabled.
79    pub fn no_gzip(mut self) -> Self {
80        self.accept.set_gzip(false);
81        self
82    }
83
84    /// Disables the Deflate encoding.
85    ///
86    /// This method is available even if the `deflate` crate feature is disabled.
87    pub fn no_deflate(mut self) -> Self {
88        self.accept.set_deflate(false);
89        self
90    }
91
92    /// Disables the Brotli encoding.
93    ///
94    /// This method is available even if the `br` crate feature is disabled.
95    pub fn no_br(mut self) -> Self {
96        self.accept.set_br(false);
97        self
98    }
99
100    /// Disables the Zstd encoding.
101    ///
102    /// This method is available even if the `zstd` crate feature is disabled.
103    pub fn no_zstd(mut self) -> Self {
104        self.accept.set_zstd(false);
105        self
106    }
107
108    /// Replace the current compression predicate.
109    ///
110    /// See [`Compression::compress_when`] for more details.
111    pub fn compress_when<C>(self, predicate: C) -> CompressionLayer<C>
112    where
113        C: Predicate,
114    {
115        CompressionLayer {
116            accept: self.accept,
117            predicate,
118            quality: self.quality,
119        }
120    }
121}
122
123#[cfg(test)]
124mod tests {
125    use super::*;
126    use crate::test_helpers::Body;
127    use http::{header::ACCEPT_ENCODING, Request, Response};
128    use http_body_util::BodyExt;
129    use std::convert::Infallible;
130    use tokio::fs::File;
131    use tokio_util::io::ReaderStream;
132    use tower::{Service, ServiceBuilder, ServiceExt};
133
134    async fn handle(_req: Request<Body>) -> Result<Response<Body>, Infallible> {
135        // Open the file.
136        let file = File::open("Cargo.toml").await.expect("file missing");
137        // Convert the file into a `Stream`.
138        let stream = ReaderStream::new(file);
139        // Convert the `Stream` into a `Body`.
140        let body = Body::from_stream(stream);
141        // Create response.
142        Ok(Response::new(body))
143    }
144
145    #[tokio::test]
146    async fn accept_encoding_configuration_works() -> Result<(), crate::BoxError> {
147        let deflate_only_layer = CompressionLayer::new()
148            .quality(CompressionLevel::Best)
149            .no_br()
150            .no_gzip();
151
152        let mut service = ServiceBuilder::new()
153            // Compress responses based on the `Accept-Encoding` header.
154            .layer(deflate_only_layer)
155            .service_fn(handle);
156
157        // Call the service with the deflate only layer
158        let request = Request::builder()
159            .header(ACCEPT_ENCODING, "gzip, deflate, br")
160            .body(Body::empty())?;
161
162        let response = service.ready().await?.call(request).await?;
163
164        assert_eq!(response.headers()["content-encoding"], "deflate");
165
166        // Read the body
167        let body = response.into_body();
168        let bytes = body.collect().await.unwrap().to_bytes();
169
170        let deflate_bytes_len = bytes.len();
171
172        let br_only_layer = CompressionLayer::new()
173            .quality(CompressionLevel::Best)
174            .no_gzip()
175            .no_deflate();
176
177        let mut service = ServiceBuilder::new()
178            // Compress responses based on the `Accept-Encoding` header.
179            .layer(br_only_layer)
180            .service_fn(handle);
181
182        // Call the service with the br only layer
183        let request = Request::builder()
184            .header(ACCEPT_ENCODING, "gzip, deflate, br")
185            .body(Body::empty())?;
186
187        let response = service.ready().await?.call(request).await?;
188
189        assert_eq!(response.headers()["content-encoding"], "br");
190
191        // Read the body
192        let body = response.into_body();
193        let bytes = body.collect().await.unwrap().to_bytes();
194
195        let br_byte_length = bytes.len();
196
197        // check the corresponding algorithms are actually used
198        // br should compresses better than deflate
199        assert!(br_byte_length < deflate_bytes_len * 9 / 10);
200
201        Ok(())
202    }
203
204    /// Test ensuring that zstd compression will not exceed an 8MiB window size; browsers do not
205    /// accept responses using 16MiB+ window sizes.
206    #[tokio::test]
207    async fn zstd_is_web_safe() -> Result<(), crate::BoxError> {
208        async fn zeroes(_req: Request<Body>) -> Result<Response<Body>, Infallible> {
209            Ok(Response::new(Body::from(vec![0u8; 18_874_368])))
210        }
211        // zstd will (I believe) lower its window size if a larger one isn't beneficial and
212        // it knows the size of the input; use an 18MiB body to ensure it would want a
213        // >=16MiB window (though it might not be able to see the input size here).
214
215        let zstd_layer = CompressionLayer::new()
216            .quality(CompressionLevel::Best)
217            .no_br()
218            .no_deflate()
219            .no_gzip();
220
221        let mut service = ServiceBuilder::new().layer(zstd_layer).service_fn(zeroes);
222
223        let request = Request::builder()
224            .header(ACCEPT_ENCODING, "zstd")
225            .body(Body::empty())?;
226
227        let response = service.ready().await?.call(request).await?;
228
229        assert_eq!(response.headers()["content-encoding"], "zstd");
230
231        let body = response.into_body();
232        let bytes = body.collect().await?.to_bytes();
233        let mut dec = zstd::Decoder::new(&*bytes)?;
234        dec.window_log_max(23)?; // Limit window size accepted by decoder to 2 ^ 23 bytes (8MiB)
235
236        std::io::copy(&mut dec, &mut std::io::sink())?;
237
238        Ok(())
239    }
240}
tower_http/compression/layer.rs

tower_http/compression/
layer.rs
