Error while posting buffer form data

[filips123]

Description:

I want to post form data with buffer to URL, but I get error The "string" argument must be one of type string, Buffer, or ArrayBuffer.

Example:

const axios = require('axios')
const FormData = require('form-data')

let avatar = Buffer.from(['00', '01', '03', '04', '05', '06', '07', '08', '09']) // Buffer data of image file
let url = 'https://example.com/' // Some URL

let formData = new FormData()
formData.append('avatar', avatar)

await axios.post(url, formData, { // Await is called inside async function
    headers: {
        'Content-Type': `multipart/form-data; boundary=${formData._boundary}`
    }
})

Error:

TypeError [ERR_INVALID_ARG_TYPE]: The "string" argument must be one of type string, Buffer, or ArrayBuffer. Received type object
      at Function.byteLength (buffer.js:516:11)
      at exports.XMLHttpRequest.send (node_modules/xmlhttprequest/lib/XMLHttpRequest.js:363:80)
      at dispatchXhrRequest (node_modules/axios/lib/adapters/xhr.js:178:13)
      at new Promise (<anonymous>)
      at xhrAdapter (node_modules/axios/lib/adapters/xhr.js:12:10)
      at dispatchRequest (node_modules/axios/lib/core/dispatchRequest.js:59:10)
      at process._tickCallback (internal/process/next_tick.js:68:7)

Environment:

• NodeJS: 10.11.0
• FormData: 2.3.3
• Axios: 0.18.0

[filips123]

This is similar to #318. However, it is old and closed and I could not fix it.

I've tried #318 (comment), but I still have same error.

[filips123]

I've fixed this using formData._streams instead of just formData. I've also added formData.getHeaders() to headers and some other changes (see form-data/form-data#414).

This is probably some temporary and quick solution so this issue should not be closed until it works better.

const axios = require('axios')
const FormData = require('form-data')

let avatar = Buffer.from(['00', '01', '03', '04', '05', '06', '07', '08', '09']) // Buffer data of image file
let url = 'https://example.com/' // Some URL

let formData = new FormData()
formData.append('avatar', avatar)

let data = ''
for (var i = 0, len = formData._streams.length; i < len; i++) {
  if (typeof formData._streams[i] !== 'function') {
    data += formData._streams[i] + '\r\n'
  }
}

await axios.post(url, data, { // Await is called inside async function
    headers: formData.getHeaders()
})

[Rmsilva1]

I've fixed this using formData._streams instead of just formData. I've also added formData.getHeaders() to headers and some other changes (see form-data/form-data#414).

This is probably some temporary and quick solution so this issue should not be closed until it works better.

const axios = require('axios')
const FormData = require('form-data')

let avatar = Buffer.from(['00', '01', '03', '04', '05', '06', '07', '08', '09']) // Buffer data of image file
let url = 'https://example.com/' // Some URL

let formData = new FormData()
formData.append('avatar', avatar)

let data = ''
for (var i = 0, len = formData._streams.length; i < len; i++) {
  if (typeof formData._streams[i] !== 'function') {
    data += formData._streams[i] + '\r\n'
  }
}

await axios.post(url, data, { // Await is called inside async function
    headers: formData.getHeaders()
})

Im having the same issue, but i have to send 3 query parameters along with the request. i did not managed to make it work with your solution. :(

[chinesedfan]

In fact, it is an issue of package form-data. And according to #2049, it has been solved.