Add zstd compression support

Co-authored-by: SeriousBug <1008124+SeriousBug@users.noreply.github.com>

Author: Copilot

Cargo.toml

@@ -19,6 +19,7 @@ rust-embed-for-web-utils = { version = "11.2.1", path = "utils" }
 chrono = { version = "0.4", default-features = false }
 flate2 = "1.0"
 brotli = "6.0"
+zstd = "0.13"
 actix-web = "4.4"
 
 [features]
@@ -46,6 +47,11 @@ name = "gzip"
 path = "tests/gzip.rs"
 required-features = ["always-embed"]
 
+[[test]]
+name = "zstd"
+path = "tests/zstd.rs"
+required-features = ["always-embed"]
+
 [[test]]
 name = "include-exclude"
 path = "tests/include-exclude.rs"

README.md

@@ -24,7 +24,7 @@ executable in exchange for better performance at runtime. In particular:
   or decompress anything at runtime.
   - If the compression makes little difference, for example a jpeg file won't
     compress much further if at all, then the compressed version is not included.
-  - You can also disable this behavior by adding an attribute `#[gzip = false]` and `#[br = false]`
+  - You can also disable this behavior by adding an attribute `#[gzip = false]`, `#[br = false]`, or `#[zstd = false]`
     When disabled, the compressed files won't be included for that embed.
 - Some metadata that is useful for web headers like `ETag` and `Last-Modified`
   are computed ahead of time and embedded into the executable. This makes it
@@ -68,8 +68,8 @@ The path for the `folder` is resolved relative to where `Cargo.toml` is.
 
 ### Disabling compression
 
-You can add `#[gzip = false]` and/or `#[br = false]` attributes to your embed to
-disable gzip and brotli compression for the files in that embed.
+You can add `#[gzip = false]`, `#[br = false]`, and/or `#[zstd = false]` attributes to your embed to
+disable gzip, brotli, and/or zstd compression for the files in that embed.
 `rust-embed-for-web` will only include compressed files where the compression
 actually makes files smaller so files that won't compress well like images or
 archives already don't include their compressed versions. However you can

impl/Cargo.toml

@@ -27,6 +27,7 @@ walkdir = "2.4.0"
 # Compression
 flate2 = "1.0"
 brotli = "6.0"
+zstd = "0.13"
 
 globset = { version = "0.4", optional = true }
 

impl/src/attributes.rs

@@ -42,6 +42,7 @@ pub(crate) fn read_attribute_config(ast: &syn::DeriveInput) -> Config {
                 "exclude" => parse_str(attribute).map(|v| config.add_exclude(v)),
                 "gzip" => parse_bool(attribute).map(|v| config.set_gzip(v)),
                 "br" => parse_bool(attribute).map(|v| config.set_br(v)),
+                "zstd" => parse_bool(attribute).map(|v| config.set_zstd(v)),
                 _ => None,
             };
         }

impl/src/compress.rs

@@ -2,6 +2,7 @@ use std::io::{BufReader, Write};
 
 use brotli::enc::BrotliEncoderParams;
 use flate2::{write::GzEncoder, Compression};
+use zstd::stream::write::Encoder as ZstdEncoder;
 
 /// Only include the compressed version if it is at least this much smaller than
 /// the uncompressed version.
@@ -39,3 +40,21 @@ pub(crate) fn compress_br(data: &[u8]) -> Option<Vec<u8>> {
         None
     }
 }
+
+pub(crate) fn compress_zstd(data: &[u8]) -> Option<Vec<u8>> {
+    let mut data_zstd: Vec<u8> = Vec::new();
+    let mut encoder = ZstdEncoder::new(&mut data_zstd, 3)
+        .expect("Failed to create zstd encoder");
+    encoder
+        .write_all(data)
+        .expect("Failed to compress zstd data");
+    encoder
+        .finish()
+        .expect("Failed to finish compression of zstd data");
+
+    if data_zstd.len() < ((data.len() as f64) * COMPRESSION_INCLUDE_THRESHOLD) as usize {
+        Some(data_zstd)
+    } else {
+        None
+    }
+}

impl/src/embed.rs

@@ -1,7 +1,7 @@
 use proc_macro2::TokenStream as TokenStream2;
 use rust_embed_for_web_utils::{get_files, Config, DynamicFile, EmbedableFile, FileEntry};
 
-use crate::compress::{compress_br, compress_gzip};
+use crate::compress::{compress_br, compress_gzip, compress_zstd};
 
 /// Anything that can be embedded into the program.
 ///
@@ -70,6 +70,11 @@ impl<'t> MakeEmbed for EmbedDynamicFile<'t> {
         } else {
             None::<Vec<u8>>.make_embed()
         };
+        let data_zstd = if self.config.should_zstd() {
+            compress_zstd(&data).make_embed()
+        } else {
+            None::<Vec<u8>>.make_embed()
+        };
         let data = data.make_embed();
         let hash = file.hash().make_embed();
         let etag = file.etag().make_embed();
@@ -83,6 +88,7 @@ impl<'t> MakeEmbed for EmbedDynamicFile<'t> {
                 #data,
                 #data_gzip,
                 #data_br,
+                #data_zstd,
                 #hash,
                 #etag,
                 #last_modified,

impl/src/lib.rs

@@ -87,7 +87,7 @@ fn impl_rust_embed_for_web(ast: &syn::DeriveInput) -> TokenStream2 {
     }
 }
 
-#[proc_macro_derive(RustEmbed, attributes(folder, prefix, include, exclude, gzip, br))]
+#[proc_macro_derive(RustEmbed, attributes(folder, prefix, include, exclude, gzip, br, zstd))]
 /// A folder that is embedded into your program.
 ///
 /// For example:

tests/compression.rs

@@ -11,6 +11,7 @@ struct Embed;
 fn html_files_are_compressed() {
     assert!(Embed::get("index.html").unwrap().data_gzip().is_some());
     assert!(Embed::get("index.html").unwrap().data_br().is_some());
+    assert!(Embed::get("index.html").unwrap().data_zstd().is_some());
 }
 
 #[test]
@@ -20,6 +21,7 @@ fn image_files_are_not_compressed() {
         .data_gzip()
         .is_none());
     assert!(Embed::get("images/flower.jpg").unwrap().data_br().is_none());
+    assert!(Embed::get("images/flower.jpg").unwrap().data_zstd().is_none());
 }
 
 #[test]
@@ -42,3 +44,11 @@ fn compression_br_roundtrip() {
     let decompressed_body = String::from_utf8_lossy(&decompressed[..]);
     assert!(decompressed_body.starts_with("<!DOCTYPE html>"));
 }
+
+#[test]
+fn compression_zstd_roundtrip() {
+    let compressed = Embed::get("index.html").unwrap().data_zstd().unwrap();
+    let decompressed = zstd::bulk::decompress(&compressed, 1024 * 1024).unwrap();
+    let decompressed_body = String::from_utf8_lossy(&decompressed[..]);
+    assert!(decompressed_body.starts_with("<!DOCTYPE html>"));
+}

tests/zstd.rs

@@ -0,0 +1,39 @@
+use rust_embed_for_web::{EmbedableFile, RustEmbed};
+
+#[derive(RustEmbed)]
+#[folder = "examples/public/"]
+struct DefaultZstd;
+
+#[derive(RustEmbed)]
+#[folder = "examples/public/"]
+#[zstd = false]
+struct FalseZstd;
+
+#[derive(RustEmbed)]
+#[folder = "examples/public/"]
+#[zstd = true]
+struct TrueZstd;
+
+#[test]
+fn zstd_is_used_by_default() {
+    let file = DefaultZstd::get("index.html").unwrap();
+    assert!(file.data_zstd().is_some());
+}
+
+#[test]
+fn zstd_is_used_when_enabled() {
+    let file = TrueZstd::get("index.html").unwrap();
+    assert!(file.data_zstd().is_some());
+}
+
+#[test]
+fn zstd_is_not_available_when_disabled() {
+    let file = FalseZstd::get("index.html").unwrap();
+    assert!(file.data_zstd().is_none());
+}
+
+#[test]
+fn image_files_dont_get_zstd_compressed() {
+    let file = DefaultZstd::get("images/flower.jpg").unwrap();
+    assert!(file.data_zstd().is_none());
+}

utils/src/config.rs

@@ -9,6 +9,7 @@ pub struct Config {
     exclude: Vec<GlobMatcher>,
     gzip: bool,
     br: bool,
+    zstd: bool,
 }
 
 impl Default for Config {
@@ -20,6 +21,7 @@ impl Default for Config {
             exclude: vec![],
             gzip: true,
             br: true,
+            zstd: true,
         }
     }
 }
@@ -56,6 +58,10 @@ impl Config {
         self.br = status;
     }
 
+    pub fn set_zstd(&mut self, status: bool) {
+        self.zstd = status;
+    }
+
     #[cfg(feature = "include-exclude")]
     pub fn get_includes(&self) -> &Vec<GlobMatcher> {
         &self.include
@@ -99,4 +105,8 @@ impl Config {
     pub fn should_br(&self) -> bool {
         self.br
     }
+
+    pub fn should_zstd(&self) -> bool {
+        self.zstd
+    }
 }