Add deflate compression support

tests/compression/Cargo.toml

@@ -16,7 +16,7 @@ pin-project = "1.0"
 prost = "0.13"
 tokio = {version = "1.0", features = ["macros", "rt-multi-thread", "net"]}
 tokio-stream = "0.1"
-tonic = {path = "../../tonic", features = ["gzip", "zstd"]}
+tonic = {path = "../../tonic", features = ["gzip", "deflate", "zstd"]}
 tower = "0.5"
 tower-http = {version = "0.6", features = ["map-response-body", "map-request-body"]}
 

tonic/Cargo.toml

@@ -25,6 +25,7 @@ version = "0.13.0"
 [features]
 codegen = ["dep:async-trait"]
 gzip = ["dep:flate2"]
+deflate = ["dep:flate2"]
 zstd = ["dep:zstd"]
 default = ["transport", "codegen", "prost"]
 prost = ["dep:prost"]

tonic/src/client/grpc.rs

@@ -404,7 +404,7 @@ impl GrpcConfig {
             .headers_mut()
             .insert(CONTENT_TYPE, GRPC_CONTENT_TYPE);
 
-        #[cfg(any(feature = "gzip", feature = "zstd"))]
+        #[cfg(any(feature = "gzip", feature = "deflate", feature = "zstd"))]
         if let Some(encoding) = self.send_compression_encodings {
             request.headers_mut().insert(
                 crate::codec::compression::ENCODING_HEADER,

tonic/src/codec/compression.rs

@@ -1,5 +1,7 @@
 use crate::{metadata::MetadataValue, Status};
 use bytes::{Buf, BufMut, BytesMut};
+#[cfg(feature = "deflate")]
+use flate2::read::{DeflateDecoder, DeflateEncoder};
 #[cfg(feature = "gzip")]
 use flate2::read::{GzDecoder, GzEncoder};
 use std::fmt;
@@ -14,7 +16,7 @@ pub(crate) const ACCEPT_ENCODING_HEADER: &str = "grpc-accept-encoding";
 /// Represents an ordered list of compression encodings that are enabled.
 #[derive(Debug, Default, Clone, Copy)]
 pub struct EnabledCompressionEncodings {
-    inner: [Option<CompressionEncoding>; 2],
+    inner: [Option<CompressionEncoding>; 3],
 }
 
 impl EnabledCompressionEncodings {
@@ -85,6 +87,9 @@ pub enum CompressionEncoding {
     #[cfg(feature = "gzip")]
     Gzip,
     #[allow(missing_docs)]
+    #[cfg(feature = "deflate")]
+    Deflate,
+    #[allow(missing_docs)]
     #[cfg(feature = "zstd")]
     Zstd,
 }
@@ -93,6 +98,8 @@ impl CompressionEncoding {
     pub(crate) const ENCODINGS: &'static [CompressionEncoding] = &[
         #[cfg(feature = "gzip")]
         CompressionEncoding::Gzip,
+        #[cfg(feature = "deflate")]
+        CompressionEncoding::Deflate,
         #[cfg(feature = "zstd")]
         CompressionEncoding::Zstd,
     ];
@@ -112,6 +119,8 @@ impl CompressionEncoding {
         split_by_comma(header_value_str).find_map(|value| match value {
             #[cfg(feature = "gzip")]
             "gzip" => Some(CompressionEncoding::Gzip),
+            #[cfg(feature = "deflate")]
+            "deflate" => Some(CompressionEncoding::Deflate),
             #[cfg(feature = "zstd")]
             "zstd" => Some(CompressionEncoding::Zstd),
             _ => None,
@@ -132,6 +141,10 @@ impl CompressionEncoding {
             b"gzip" if enabled_encodings.is_enabled(CompressionEncoding::Gzip) => {
                 Ok(Some(CompressionEncoding::Gzip))
             }
+            #[cfg(feature = "deflate")]
+            b"deflate" if enabled_encodings.is_enabled(CompressionEncoding::Deflate) => {
+                Ok(Some(CompressionEncoding::Deflate))
+            }
             #[cfg(feature = "zstd")]
             b"zstd" if enabled_encodings.is_enabled(CompressionEncoding::Zstd) => {
                 Ok(Some(CompressionEncoding::Zstd))
@@ -170,6 +183,8 @@ impl CompressionEncoding {
         match self {
             #[cfg(feature = "gzip")]
             CompressionEncoding::Gzip => "gzip",
+            #[cfg(feature = "deflate")]
+            CompressionEncoding::Deflate => "deflate",
             #[cfg(feature = "zstd")]
             CompressionEncoding::Zstd => "zstd",
         }
@@ -217,6 +232,15 @@ pub(crate) fn compress(
             );
             std::io::copy(&mut gzip_encoder, &mut out_writer)?;
         }
+        #[cfg(feature = "deflate")]
+        CompressionEncoding::Deflate => {
+            let mut deflate_encoder = DeflateEncoder::new(
+                &decompressed_buf[0..len],
+                // FIXME: support customizing the compression level
+                flate2::Compression::new(6),
+            );
+            std::io::copy(&mut deflate_encoder, &mut out_writer)?;
+        }
         #[cfg(feature = "zstd")]
         CompressionEncoding::Zstd => {
             let mut zstd_encoder = Encoder::new(
@@ -247,7 +271,7 @@ pub(crate) fn decompress(
         ((estimate_decompressed_len / buffer_growth_interval) + 1) * buffer_growth_interval;
     out_buf.reserve(capacity);
 
-    #[cfg(any(feature = "gzip", feature = "zstd"))]
+    #[cfg(any(feature = "gzip", feature = "deflate", feature = "zstd"))]
     let mut out_writer = out_buf.writer();
 
     match settings.encoding {
@@ -256,6 +280,11 @@ pub(crate) fn decompress(
             let mut gzip_decoder = GzDecoder::new(&compressed_buf[0..len]);
             std::io::copy(&mut gzip_decoder, &mut out_writer)?;
         }
+        #[cfg(feature = "deflate")]
+        CompressionEncoding::Deflate => {
+            let mut deflate_decoder = DeflateDecoder::new(&compressed_buf[0..len]);
+            std::io::copy(&mut deflate_decoder, &mut out_writer)?;
+        }
         #[cfg(feature = "zstd")]
         CompressionEncoding::Zstd => {
             let mut zstd_decoder = Decoder::new(&compressed_buf[0..len])?;
@@ -282,7 +311,7 @@ pub enum SingleMessageCompressionOverride {
 
 #[cfg(test)]
 mod tests {
-    #[cfg(any(feature = "gzip", feature = "zstd"))]
+    #[cfg(any(feature = "gzip", feature = "deflate", feature = "zstd"))]
     use http::HeaderValue;
 
     use super::*;
@@ -300,13 +329,13 @@ mod tests {
         const GZIP: HeaderValue = HeaderValue::from_static("gzip,identity");
 
         let encodings = EnabledCompressionEncodings {
-            inner: [Some(CompressionEncoding::Gzip), None],
+            inner: [Some(CompressionEncoding::Gzip), None, None],
         };
 
         assert_eq!(encodings.into_accept_encoding_header_value().unwrap(), GZIP);
 
         let encodings = EnabledCompressionEncodings {
-            inner: [None, Some(CompressionEncoding::Gzip)],
+            inner: [None, None, Some(CompressionEncoding::Gzip)],
         };
 
         assert_eq!(encodings.into_accept_encoding_header_value().unwrap(), GZIP);
@@ -318,43 +347,45 @@ mod tests {
         const ZSTD: HeaderValue = HeaderValue::from_static("zstd,identity");
 
         let encodings = EnabledCompressionEncodings {
-            inner: [Some(CompressionEncoding::Zstd), None],
+            inner: [Some(CompressionEncoding::Zstd), None, None],
         };
 
         assert_eq!(encodings.into_accept_encoding_header_value().unwrap(), ZSTD);
 
         let encodings = EnabledCompressionEncodings {
-            inner: [None, Some(CompressionEncoding::Zstd)],
+            inner: [None, None, Some(CompressionEncoding::Zstd)],
         };
 
         assert_eq!(encodings.into_accept_encoding_header_value().unwrap(), ZSTD);
     }
 
     #[test]
-    #[cfg(all(feature = "gzip", feature = "zstd"))]
+    #[cfg(all(feature = "gzip", feature = "deflate", feature = "zstd"))]
     fn convert_gzip_and_zstd_into_header_value() {
         let encodings = EnabledCompressionEncodings {
             inner: [
                 Some(CompressionEncoding::Gzip),
+                Some(CompressionEncoding::Deflate),
                 Some(CompressionEncoding::Zstd),
             ],
         };
 
         assert_eq!(
             encodings.into_accept_encoding_header_value().unwrap(),
-            HeaderValue::from_static("gzip,zstd,identity"),
+            HeaderValue::from_static("gzip,deflate,zstd,identity"),
         );
 
         let encodings = EnabledCompressionEncodings {
             inner: [
                 Some(CompressionEncoding::Zstd),
+                Some(CompressionEncoding::Deflate),
                 Some(CompressionEncoding::Gzip),
             ],
         };
 
         assert_eq!(
             encodings.into_accept_encoding_header_value().unwrap(),
-            HeaderValue::from_static("zstd,gzip,identity"),
+            HeaderValue::from_static("zstd,deflate,gzip,identity"),
         );
     }
 }

tonic/src/lib.rs

@@ -35,6 +35,8 @@
 //! - `prost`: Enables the [`prost`] based gRPC [`Codec`] implementation. Enabled by default.
 //! - `gzip`: Enables compressing requests, responses, and streams. Depends on [`flate2`].
 //!   Not enabled by default.
+//! - `deflate`: Enables compressing requests, responses, and streams. Depends on [`flate2`].
+//!   Not enabled by default.
 //! - `zstd`: Enables compressing requests, responses, and streams. Depends on [`zstd`].
 //!   Not enabled by default.
 //!

tonic/src/response.rs

@@ -120,7 +120,7 @@ impl<T> Response<T> {
     /// **Note**: This only has effect on responses to unary requests and responses to client to
     /// server streams. Response streams (server to client stream and bidirectional streams) will
     /// still be compressed according to the configuration of the server.
-    #[cfg(feature = "gzip")]
+    #[cfg(any(feature = "gzip", feature = "deflate", feature = "zstd"))]
     pub fn disable_compression(&mut self) {
         self.extensions_mut()
             .insert(crate::codec::compression::SingleMessageCompressionOverride::Disable);

tonic/src/server/grpc.rs

@@ -435,7 +435,7 @@ where
             .headers
             .insert(http::header::CONTENT_TYPE, GRPC_CONTENT_TYPE);
 
-        #[cfg(any(feature = "gzip", feature = "zstd"))]
+        #[cfg(any(feature = "gzip", feature = "deflate", feature = "zstd"))]
         if let Some(encoding) = accept_encoding {
             // Set the content encoding
             parts.headers.insert(