How to upload a file to Cloudinary from page.server? - node.js

Question

I Want to upload a file to Cloudinary with their nodejs SDK. I'm using Sveltekit and need to understand the way how it needs to be done. The flow:
Frontend: page.svelte Uploading a file with a <form>, submitting and calling server action ?/upload
<form
method="post"
enctype="multipart/form-data"
use:enhance
action="?/upload"
<input
class="hidden"
name="image"
id="file-to-upload"
type="file"
accept=".png,.jpg"
/>
<button class="border bg-orange-400 rounded py-2 text-sm"
>Upload!</button
>
</form>
Backend: +page.server.ts
import { v2 as cloudinary, type UploadApiResponse } from 'cloudinary'
import type { Actions } from './$types';
export const actions = {
upload: async ({request}) => {
const data = request.formData();
const file = (await data).get('image') as File
if (file){
const buffer = await file.arrayBuffer();
const stream = await file.stream();
const upload_stream = cloudinary.uploader.upload_stream((error, image) => {
?????
});
} else {
console.error('no file to upload')
}
}
} satisfies Actions;
Reads FormData and trying to upload submitted file to Cloudinary. But how to do this? Cloudinary has some methods like upload_stream but i cant figure out the way.
I've tried common cloudinary.uploader.upload function, but it wants a string as an input.
And i have only buffer and stream from FormData. I don't want to create base64 from file contents or upload a file to Cloudinary directly from browser.
Seems like I need to convert recieved FormData's file to another format, which can be successfully uploaded to cloudinary's upload_stream() function, for example. I really need help to make understanding how to correctly pass it from SvelteKit's backend to Cloudinary in the right way.
Any help will be appreciated.

Answer 1

So i found a solution. The trick is to convert file's ArrayBuffer to node's Buffer, so then Cloudinary's upload_stream works like a charm. Because of callback-nature of this function, i wrapped it in Promise.
async upload(file: File) {
const arrayBuffer = await file.arrayBuffer();
const buffer = Buffer.from(arrayBuffer) // <-- convert to Buffer
return new Promise((resolve, reject) => {
cloudinary.uploader.upload_stream({ resource_type: "image" }, onDone).end(buffer)
function onDone(error, result) {
if (error) {
return reject({ success: false, error });
}
return resolve({ success: true, result })
}
});
}