upload limit of filesize for multipart ignored

[tessus]

Expected Behavior

total_limit should be honored.

        App::new()
            .app_data(Data::clone(&config))
            .app_data(Data::new(http_client))
            .app_data(
                MultipartFormConfig::default()
                    .total_limit(
                        Byte::parse_str(server_config.max_content_length.to_string(), true)
                            .expect("cannot parse byte")
                            .as_u64()
                            .try_into()
                            .unwrap(),
                    )
                    .memory_limit(10 * 1024 * 1024)
                    .error_handler(handle_multipart_error),
            )
            .wrap(Logger::new(
                "%{r}a \"%r\" %s %b \"%{Referer}i\" \"%{User-Agent}i\" %T",
            ))

Current Behavior

total_limit is ignored.
We also tried the middleware approach, but it doesn't work. With the middleware, you get an error message only AFTER the entire file has been uploaded.
With total_limit nothing happens at all. The file is just uploaded, no matter the size.

Possible Solution

I do not know.

Steps to Reproduce (for bugs)

1. for middleware: git master https://github.com/orhun/rustypaste/commits/master/
2. for total_upload: fix(server): upload limit orhun/rustypaste#360
3. start rustypaste server
4. upload file larger than max specified in config

Context

I have searched the documentation, Stackoverflow, and other websites. Unfortunately all the info I found was either not helpful or did not work.

If this is not a bug, please convert it to a discussion.

Your Environment

• Rust Version (I.e, output of rustc -V): rustc 1.85.0 (4d91de4e4 2025-02-17) doesn't matter, the problem has existed for a long time
• Actix Web Version: 4.9.0

[JohnTitor]

I checked your code and the cause is you're using Multipart, not MultipartForm. The MultipartFormConfig only applies to MultipartForm, see https://docs.rs/actix-multipart/latest/actix_multipart/form/struct.MultipartForm.html and other related docs.

An example from our test:

actix-web/actix-multipart/src/form/mod.rs

Lines 736 to 760 in 465c866

	#[actix_rt::test]
	async fn test_memory_limits() {
	let srv = actix_test::start(|| {
	App::new()
	.route("/text", web::post().to(test_upload_limits_memory))
	.route("/file", web::post().to(test_upload_limits_file))
	.app_data(
	MultipartFormConfig::default()
	.memory_limit(20)
	.total_limit(usize::MAX),
	)
	});
	// Exceeds the 20 byte memory limit
	let mut form = multipart::Form::default();
	form.add_text("field", "this string is 28 bytes long");
	let response = send_form(&srv, form, "/text").await;
	assert_eq!(response.status(), StatusCode::BAD_REQUEST);
	// Memory limit should not apply when the data is being streamed to disk
	let mut form = multipart::Form::default();
	form.add_text("field", "this string is 28 bytes long");
	let response = send_form(&srv, form, "/file").await;
	assert_eq!(response.status(), StatusCode::OK);
	}