NodeJS, Axios - post file from local server to another server

The 2 oldest answers did not work for me. This, however, did the trick:

const FormData = require('form-data'); // npm install --save form-data

const form = new FormData();
form.append('file', fs.createReadStream(file.path));

const request_config = {
  headers: {
    'Authorization': `Bearer ${access_token}`,
    ...form.getHeaders()
  }
};

return axios.post(url, form, request_config);

form.getHeaders() returns an Object with the content-type as well as the boundary.
For example:

{ "content-type": "multipart/form-data; boundary=-------------------0123456789" }

I'm thinking the createReadStream is your issue because its async. try this. Since createReadStream extends the event emitter, we can "listen" for when it finishes/ends.

var newFile = fs.createReadStream(file.path);

// personally I'd function out the inner body here and just call 
// to the function and pass in the newFile
newFile.on('end', function() {
  const form_data = new FormData();
  form_data.append("file", newFile, "filename.ext");
  const request_config = {
    method: "post",
    url: url,
    headers: {
        "Authorization": "Bearer " + access_token,
        "Content-Type": "multipart/form-data"
    },
    data: form_data
  };
  return axios(request_config);
});

This is what you really need:

const form_data = new FormData();
form_data.append("file", fs.createReadStream(file.path));

const request_config = {
  headers: {
    "Authorization": "Bearer " + access_token,
    "Content-Type": "multipart/form-data"
  },
  data: form_data
};

return axios
  .post(url, form_data, request_config);

In my case, fs.createReadStream(file.path) did not work.
I had to use buffer instead.

const form = new FormData();
form.append('file', fs.readFileSync(filePath), fileName);

const config = {
  headers: {
    Authorization: `Bearer ${auth.access_token}`,
    ...form.getHeaders(),
  },
};

axios.post(api, form.getBuffer(), config);

I have made an interceptor you can connect to axios to handle this case in node: axios-form-data. Any feedback would be welcome.

• npm i axios-form-data
• example:

import axiosFormData from 'axios-form-data';
import axios from 'axios';

// connect axiosFormData interceptor to axios
axios.interceptors.request.use(axiosFormData);

// send request with a file in it, it automatically becomes form-data
const response = await axios.request({
  method: 'POST',
  url: 'http://httpbin.org/post',
  data: {
    nonfile: 'Non-file value',
    // if there is at least one streamable value, the interceptor wraps the data into FormData
    file: createReadStream('somefile'),
  },
});

// response should show "files" with file content, "form" with other values
// and multipart/form-data with random boundary as request header
console.log(response.data);

I had a same issue, I had a "pdf-creator-service" for generate PDF document from html.

I use mustache template engine for create HTML document - https://www.npmjs.com/package/mustache Mustache.render function returns html as a string what do I need to do to pass it to the pdf-generator-service ? So lets see my suggestion bellow

//...

async function getPdfDoc(props: {foo: string, bar: string}): Promise<Buffer> {
    const temlateFile = readFileSync(joinPath(process.cwd(), 'file.html'))

    mustache.render(temlateFile, props)
    const readableStream = this.getReadableStreamFromString(htmlString)

    const formData = new FormData() // from 'form-data'
    formData.append('file', options.file, { filename: options.fileName })
    const formHeaders = formData.getHeaders()

    return await axios.send<Buffer>(
      {
        method: 'POST',
        url: 'https://pdf-generator-service-url/pdf',
        data: formData,
        headers: {
          ...formHeaders,
        },
        responseType: 'arraybuffer', // ! important
      },
    )

}

getReadableStreamFromString(str: string): Readable {
    const bufferHtmlString = Buffer.from(str)
    const readableStream = new Readable() // from 'stream'

    readableStream._read = () => null // workaround error
    readableStream.push(bufferHtmlString)
    readableStream.push(null) // mark end of stream

    return readableStream
}

For anyone who wants to upload files from their local filesystem (actually from anywhere with the right streams architecture) with axios and doesn't want to use any external packages (like form-data).

Just create a readable stream and plug it right into axios request function like so:

await axios.put(
  url,
  fs.createReadStream(path_to_file)
) 

Axios accepts data argument of type Stream in node context.

Works fine for me at least in Node v.16.13.1 and with axios v.0.27.2