form-data

AsyncRead/AsyncWrite/Stream for `multipart/form-data` ^rfc7578

Features

• Stream: Form, Field

• AsyncRead/Read: Field, so easy read/copy field data to anywhere.

• Fast: Hyper supports bigger buffer by defaults, over 8KB, up to 512KB possible.

  AsyncRead is limited to 8KB. So if we want to receive large buffer, and save them to writer or file. See hyper example:

  • Set max_buf_size to FormData, form_data.set_max_buf_size(512 * 1024)?;

  • Use copy_to, copy bigger buffer to a writer(AsyncRead), field.copy_to(&mut writer)

  • Use copy_to_file, copy bigger buffer to a file(File), field.copy_to_file(&mut file)

• Preparse headers of part

Example

Request payload, the example from jaydenseric/graphql-multipart-request-spec.

--------------------------627436eaefdbc285
Content-Disposition: form-data; name="operations"

[{ "query": "mutation ($file: Upload!) { singleUpload(file: $file) { id } }", "variables": { "file": null } }, { "query": "mutation($files: [Upload!]!) { multipleUpload(files: $files) { id } }", "variables": { "files": [null, null] } }]
--------------------------627436eaefdbc285
Content-Disposition: form-data; name="map"

{ "0": ["0.variables.file"], "1": ["1.variables.files.0"], "2": ["1.variables.files.1"] }
--------------------------627436eaefdbc285
Content-Disposition: form-data; name="0"; filename="a.txt"
Content-Type: text/plain

Alpha file content.

--------------------------627436eaefdbc285
Content-Disposition: form-data; name="1"; filename="b.txt"
Content-Type: text/plain

Bravo file content.

--------------------------627436eaefdbc285
Content-Disposition: form-data; name="2"; filename="c.txt"
Content-Type: text/plain

Charlie file content.

--------------------------627436eaefdbc285--

tests/hyper-body.rs

use anyhow::Result;
use async_fs::File;
use bytes::BytesMut;
use tempfile::tempdir;

use futures_util::{
    io::{self, AsyncReadExt, AsyncWriteExt},
    stream::{self, TryStreamExt},
};
use http_body_util::StreamBody;

use form_data::*;

#[path = "./lib/mod.rs"]
mod lib;

use lib::{tracing_init, Limited};

#[tokio::test]
async fn hyper_body() -> Result<()> {
    tracing_init()?;

    let payload = File::open("tests/fixtures/graphql.txt").await?;
    let stream = Limited::random_with(payload, 256);
    let limit = stream.limit();

    let body = StreamBody::new(stream);
    let mut form = FormData::new(body, "------------------------627436eaefdbc285");
    form.set_max_buf_size(limit)?;

    while let Some(mut field) = form.try_next().await? {
        assert!(!field.consumed());
        assert_eq!(field.length, 0);

        match field.index {
            0 => {
                assert_eq!(field.name, "operations");
                assert_eq!(field.filename, None);
                assert_eq!(field.content_type, None);

                // reads chunks
                let mut buffer = BytesMut::new();
                while let Some(buf) = field.try_next().await? {
                    buffer.extend_from_slice(&buf);
                }

                assert_eq!(buffer, "[{ \"query\": \"mutation ($file: Upload!) { singleUpload(file: $file) { id } }\", \"variables\": { \"file\": null } }, { \"query\": \"mutation($files: [Upload!]!) { multipleUpload(files: $files) { id } }\", \"variables\": { \"files\": [null, null] } }]");
                assert_eq!(field.length, buffer.len());

                assert!(field.consumed());

                tracing::info!("{:#?}", field);
            }
            1 => {
                assert_eq!(field.name, "map");
                assert_eq!(field.filename, None);
                assert_eq!(field.content_type, None);

                // reads bytes
                let buffer = field.bytes().await?;

                assert_eq!(buffer, "{ \"0\": [\"0.variables.file\"], \"1\": [\"1.variables.files.0\"], \"2\": [\"1.variables.files.1\"] }");
                assert_eq!(field.length, buffer.len());

                assert!(field.consumed());

                tracing::info!("{:#?}", field);
            }
            2 => {
                tracing::info!("{:#?}", field);

                assert_eq!(field.name, "0");
                assert_eq!(field.filename, Some("a.txt".into()));
                assert_eq!(field.content_type, Some(mime::TEXT_PLAIN));

                let dir = tempdir()?;

                let filename = field.filename.as_ref().unwrap();
                let filepath = dir.path().join(filename);

                let mut writer = File::create(&filepath).await?;

                let bytes = io::copy(field, &mut writer).await?;
                writer.close().await?;

                // async ?
                let metadata = std::fs::metadata(&filepath)?;
                assert_eq!(metadata.len(), bytes);

                let mut reader = File::open(&filepath).await?;
                let mut contents = Vec::new();
                reader.read_to_end(&mut contents).await?;
                assert_eq!(contents, "Alpha file content.\r\n".as_bytes());

                dir.close()?;
            }
            3 => {
                assert_eq!(field.name, "1");
                assert_eq!(field.filename, Some("b.txt".into()));
                assert_eq!(field.content_type, Some(mime::TEXT_PLAIN));

                let mut buffer = Vec::with_capacity(4);
                let bytes = field.read_to_end(&mut buffer).await?;

                assert_eq!(buffer, "Bravo file content.\r\n".as_bytes());
                assert_eq!(field.length, bytes);
                assert_eq!(field.length, buffer.len());

                tracing::info!("{:#?}", field);
            }
            4 => {
                assert_eq!(field.name, "2");
                assert_eq!(field.filename, Some("c.txt".into()));
                assert_eq!(field.content_type, Some(mime::TEXT_PLAIN));

                let mut string = String::new();
                let bytes = field.read_to_string(&mut string).await?;

                assert_eq!(string, "Charlie file content.\r\n");
                assert_eq!(field.length, bytes);
                assert_eq!(field.length, string.len());

                tracing::info!("{:#?}", field);
            }
            _ => {}
        }
    }

    let state = form.state();
    let state = state
        .try_lock()
        .map_err(|e| Error::TryLockError(e.to_string()))?;

    assert!(state.eof());
    assert_eq!(state.total(), 5);
    assert_eq!(state.len(), 1027);

    Ok(())
}

License

^{Licensed under either of Apache License, Version 2.0 or MIT license at your option.}
_{Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.}