Multipart file upload error on Lambda.

[uygunbodur]

Bug Report

Version

axum = { version = "0.7.5", features = ["multipart"] }

├── axum v0.7.5 │/tmp/db630554-670d-4dff-999f-cf92afe0cc30th2.jpeg
│ ├── axum-core v0.4.3

Platform

Linux
Handler: rust.handler
Runtime: provided.al2023

Crates

axum = { version = "0.7.5", features = ["multipart"] }
chrono = "0.4.38"
dotenv = "0.15.0"
jsonwebtoken = "9.3.0"
lambda_http = "0.13.0"
rand = "0.8.5"
serde = { version = "1.0.204", features = ["derive"] }
serde_json = "1.0.120"
sha2 = "0.10.8"
sqlx = { version = "0.8.0", features = ["runtime-tokio-rustls", "postgres","uuid"] }
once_cell = "1.19.0"

tokio = { version = "1", features = ["macros", "full"] }
tower-http = { version = "0.5.2", features = ["trace", "cors","limit"] }
tracing = "0.1.40"
tracing-subscriber = "0.3.18"
uuid = { version = "1.10.0", features = ["v4","serde"] }
aws-config = { version = "1.5.5", features = ["behavior-version-latest"] }
aws-sdk-s3 = "1.46.0"

Description

I'm working on an API with Rust Axum Lambda, trying to save files to S3. There's no issue on my local machine, but on Lambda, the file size received from multipart is nearly twice as large as the original file, and the file saved to S3 is corrupted.

pub async fn upload(mut multipart: Multipart) -> Result<Json, AppError> {

return match upload_file(&mut multipart).await {
    Ok(url) => Ok(Json(json!({"url": url}))),
    Err(err) => {
        tracing::error!("ERR--> {}", err);
        Err(AppError::NotFound)
    }
};

}

pub async fn upload_file(multipart: &mut Multipart) -> Result<String, Box> {
let config = aws_config::load_defaults(BehaviorVersion::v2024_03_28()).await;
let s3_client = aws_sdk_s3::Client::new(&config);
let bucket_name = BUCKET.to_string();
tracing::info!("---> {}", bucket_name);

while let Some(field) = multipart.next_field().await? {
    let filename = field.file_name().unwrap_or("unknown").to_string();
    tracing::info!("Info --> {}", filename);
    let content_type = field.content_type().unwrap_or("image/jpeg").to_string();

    let data = field.bytes().await?;
    tracing::info!("****** -> {}", data.len());

    // let data = field.bytes().await?;

    // let body = field
    //     .bytes()
    //     .await
    //     .map(|data| ByteStream::from(data.to_vec()))?;

    let body = ByteStream::from(data);

    let key = format!("posts/{}-{}", Uuid::new_v4(), filename);
    tracing::info!("Key --> {}", key);
    tracing::info!("Content type --> {}", content_type);

    let resp = s3_client
        .put_object()
        .bucket(&bucket_name)
        .content_type(&content_type)
        .key(&key)
        .body(body)
        .send()
        .await?;
    tracing::info!("Upload success. Version: {:?}", resp.version_id);

}