Converts a file into reqwest::async::multipart::Part

file_to_part.rs

use bytes::{Bytes, BytesMut};
use reqwest::r#async::multipart::Part;
use std::{io, path::Path};
use tokio::{
    codec::{Decoder, FramedRead},
    prelude::*,
};

struct FileCodec;
impl Decoder for FileCodec {
    type Item = Bytes;
    type Error = io::Error;

    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
        Ok(Some(src.take().freeze()))
    }
}

fn file_to_chunks<P>(path: P) -> impl Stream<Item = Bytes, Error = io::Error>
where
    P: AsRef<Path> + Send + 'static,
{
    tokio::fs::File::open(path)
        .map(|file| FramedRead::new(file, FileCodec))
        .flatten_stream()
}

pub fn file_to_part<P>(path: P) -> Part
where
    P: AsRef<Path> + Send + 'static,
{
    Part::stream(file_to_chunks(path))
}