Read file from Amazon S3 with nodeJS and post it to another server with axios

Question

Im trying to read a file (image) from amazon S3 and post it to another server with multipart/form .

  let imageParams = { Bucket: 'my-bucket', Key: 'imageName.jpg' };

  let formData = new FormData();

  formData.append('file', s3.getObject(imageParams).createReadStream());

  let apiResponse = await api.post("/fileUpload", formData,
    { params: { token: process.env.API_TOKEN } }, 
    { headers: {'Content-Type': 'multipart/form-data' } } );

But im not managing it to work, it returns me:

Error: Request failed with status code 415

maybe im misunderstanding how the createReadStream() works?

Answer 1

Use concat for pipe the stream. Otherwise form data send only the first chunk of stream, and the server don't know how to handle it.

For example

const axios = require('axios');
const {S3} = require('aws-sdk');
const FormData = require('form-data');
const s3 = new S3();
var concat = require('concat-stream')

const api = axios.default.create({
    baseURL: 'http://example.com',

})

const readStream = s3.getObject({Bucket: 'bucket', Key: 'file'}).createReadStream();
readStream.pipe(concat(filebuffer => {
    const formData = new FormData();
    formData.append('file', filebuffer);
    formData.getLength((err, length) => {
        console.log(length)
        const headers = formData.getHeaders({'content-length': length})
        console.log({headers})
        return api({
            method: 'post',
            url: "/upload",
            headers: headers,
            data: formData
        })
    })

}))