Select compression algorithm using features flags (#2250)

Add compress-* feature flags in actix-http / actix-web / awc.
This allow enable / disable not wanted compression algorithm.

awc/CHANGES.md

@@ -2,11 +2,15 @@
 
 ## Unreleased - 2021-xx-xx
 
+### Changed
+
+* Change compression algorithm features flags. [#2250]
+
+[#2250]: https://github.com/actix/actix-web/pull/2250
 
 ## 3.0.0-beta.6 - 2021-06-17
 * No significant changes since 3.0.0-beta.5.
 
-
 ## 3.0.0-beta.5 - 2021-04-17
 ### Removed
 * Deprecated methods on `ClientRequest`: `if_true`, `if_some`. [#2148]

awc/Cargo.toml

@@ -24,10 +24,10 @@ path = "src/lib.rs"
 
 [package.metadata.docs.rs]
 # features that docs.rs will build with
-features = ["openssl", "rustls", "compress", "cookies"]
+features = ["openssl", "rustls", "compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
 [features]
-default = ["compress", "cookies"]
+default = ["compress-brotli", "compress-gzip", "compress-zstd", "cookies"]
 
 # openssl
 openssl = ["tls-openssl", "actix-http/openssl"]
@@ -35,8 +35,12 @@ openssl = ["tls-openssl", "actix-http/openssl"]
 # rustls
 rustls = ["tls-rustls", "actix-http/rustls"]
 
-# content-encoding support
-compress = ["actix-http/compress"]
+# Brotli algorithm content-encoding support
+compress-brotli = ["actix-http/compress-brotli", "__compress"]
+# Gzip and deflate algorithms content-encoding support
+compress-gzip = ["actix-http/compress-gzip", "__compress"]
+# Zstd algorithm content-encoding support
+compress-zstd = ["actix-http/compress-zstd", "__compress"]
 
 # cookie parsing and cookie jar
 cookies = ["cookie"]
@@ -44,6 +48,10 @@ cookies = ["cookie"]
 # trust-dns as dns resolver
 trust-dns = ["actix-http/trust-dns"]
 
+# Internal (PRIVATE!) features used to aid testing and cheking feature status.
+# Don't rely on these whatsoever. They may disappear at anytime.
+__compress = []
+
 [dependencies]
 actix-codec = "0.4.0"
 actix-service = "2.0.0"
@@ -52,6 +60,7 @@ actix-rt = { version = "2.1", default-features = false }
 
 base64 = "0.13"
 bytes = "1"
+cfg-if = "1"
 cookie = { version = "0.15", features = ["percent-encode"], optional = true }
 derive_more = "0.99.5"
 futures-core = { version = "0.3.7", default-features = false }

awc/src/request.rs

@@ -8,7 +8,7 @@ use actix_http::{
     body::Body,
     http::{
         header::{self, IntoHeaderPair},
-        uri, ConnectionType, Error as HttpError, HeaderMap, HeaderValue, Method, Uri, Version,
+        ConnectionType, Error as HttpError, HeaderMap, HeaderValue, Method, Uri, Version,
     },
     RequestHead,
 };
@@ -22,11 +22,6 @@ use crate::{
     ClientConfig,
 };
 
-#[cfg(feature = "compress")]
-const HTTPS_ENCODING: &str = "br, gzip, deflate";
-#[cfg(not(feature = "compress"))]
-const HTTPS_ENCODING: &str = "br";
-
 /// An HTTP Client request builder
 ///
 /// This type can be used to construct an instance of `ClientRequest` through a
@@ -480,22 +475,37 @@ impl ClientRequest {
 
         let mut slf = self;
 
+        // Set Accept-Encoding HTTP header depending on enabled feature.
+        // If decompress is not ask, then we are not able to find which encoding is
+        // supported, so we cannot guess Accept-Encoding HTTP header.
         if slf.response_decompress {
-            let https = slf
-                .head
-                .uri
-                .scheme()
-                .map(|s| s == &uri::Scheme::HTTPS)
-                .unwrap_or(true);
+            // Set Accept-Encoding with compression algorithm awc is built with.
+            #[cfg(feature = "__compress")]
+            let accept_encoding = {
+                let mut encoding = vec![];
 
-            if https {
-                slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, HTTPS_ENCODING));
-            } else {
-                #[cfg(feature = "compress")]
+                #[cfg(feature = "compress-brotli")]
+                encoding.push("br");
+
+                #[cfg(feature = "compress-gzip")]
                 {
-                    slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, "gzip, deflate"));
+                    encoding.push("gzip");
+                    encoding.push("deflate");
                 }
+
+                #[cfg(feature = "compress-zstd")]
+                encoding.push("zstd");
+
+                assert!(!encoding.is_empty(), "encoding cannot be empty unless __compress feature has been explictily enabled.");
+                encoding.join(", ")
             };
+
+            // Otherwise tell the server, we do not support any compression algorithm.
+            // So we clearly indicate that we do want identity encoding.
+            #[cfg(not(feature = "__compress"))]
+            let accept_encoding = "identity";
+
+            slf = slf.insert_header_if_none((header::ACCEPT_ENCODING, accept_encoding));
         }
 
         Ok(slf)

awc/src/sender.rs

@@ -22,7 +22,7 @@ use derive_more::From;
 use futures_core::Stream;
 use serde::Serialize;
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 use actix_http::{encoding::Decoder, http::header::ContentEncoding, Payload, PayloadStream};
 
 use crate::{
@@ -91,7 +91,7 @@ impl SendClientRequest {
     }
 }
 
-#[cfg(feature = "compress")]
+#[cfg(feature = "__compress")]
 impl Future for SendClientRequest {
     type Output = Result<ClientResponse<Decoder<Payload<PayloadStream>>>, SendRequestError>;
 
@@ -131,7 +131,7 @@ impl Future for SendClientRequest {
     }
 }
 
-#[cfg(not(feature = "compress"))]
+#[cfg(not(feature = "__compress"))]
 impl Future for SendClientRequest {
     type Output = Result<ClientResponse, SendRequestError>;