Small JSON performance optimizations

abdolence · Aug 7, 2022 · 1695985 · 1695985
1 parent 95bebd8
commit 1695985
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Showing 3 changed files with 20 additions and 22 deletions.
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
@@ -14,4 +14,4 @@ jobs:
           profile: minimal
           toolchain: stable
           components: rustfmt, clippy
-      - run: cargo fmt -- --check && cargo clippy -- -Dwarnings && cargo test --all-features
+      - run: cargo fmt -- --check && cargo clippy --all-features -- -Dwarnings && cargo test --all-features
diff --git a/Cargo.toml b/Cargo.toml
@@ -11,7 +11,7 @@ license = "Apache-2.0"
 name = "axum-streams"
 readme = "README.md"
 include = ["Cargo.toml", "src/**/*.rs", "README.md", "LICENSE"]
-version = "0.5.0"
+version = "0.5.1"
 
 [badges]
 maintenance = { status = "actively-developed" }

diff --git a/src/json_formats.rs b/src/json_formats.rs
@@ -1,8 +1,10 @@
 use crate::stream_format::StreamingFormat;
+use bytes::{BufMut, BytesMut};
 use futures_util::stream::BoxStream;
 use futures_util::StreamExt;
 use http::HeaderMap;
 use serde::Serialize;
+use std::io::Write;
 
 pub struct JsonArrayStreamFormat;
 
@@ -22,16 +24,14 @@ where
     ) -> BoxStream<'b, Result<axum::body::Bytes, axum::Error>> {
         let stream_bytes: BoxStream<Result<axum::body::Bytes, axum::Error>> = Box::pin({
             stream.enumerate().map(|(index, obj)| {
-                let mut output = vec![];
-                serde_json::to_vec::<T>(&obj)
-                    .map(|obj_vec| {
-                        if index != 0 {
-                            output.extend(JSON_ARRAY_SEP_BYTES)
-                        }
-                        output.extend(obj_vec);
-                        axum::body::Bytes::from(output)
-                    })
-                    .map_err(axum::Error::new)
+                let mut buf = BytesMut::new().writer();
+                if index != 0 {
+                    buf.write_all(JSON_ARRAY_SEP_BYTES).unwrap();
+                }
+                match serde_json::to_writer(&mut buf, &obj) {
+                    Ok(_) => Ok(buf.into_inner().freeze()),
+                    Err(e) => Err(axum::Error::new(e)),
+                }
             })
         });
 
@@ -76,16 +76,14 @@ where
     ) -> BoxStream<'b, Result<axum::body::Bytes, axum::Error>> {
         let stream_bytes: BoxStream<Result<axum::body::Bytes, axum::Error>> = Box::pin({
             stream.enumerate().map(|(index, obj)| {
-                let mut output = vec![];
-                serde_json::to_vec::<T>(&obj)
-                    .map(|obj_vec| {
-                        if index != 0 {
-                            output.extend(JSON_NL_SEP_BYTES)
-                        }
-                        output.extend(obj_vec);
-                        axum::body::Bytes::from(output)
-                    })
-                    .map_err(axum::Error::new)
+                let mut buf = BytesMut::new().writer();
+                if index != 0 {
+                    buf.write_all(JSON_NL_SEP_BYTES).unwrap();
+                }
+                match serde_json::to_writer(&mut buf, &obj) {
+                    Ok(_) => Ok(buf.into_inner().freeze()),
+                    Err(e) => Err(axum::Error::new(e)),
+                }
             })
         });