Fetch - POST - use stream as body?

[KevinSoulat]

Details

Hi guys,

Related to this post #4118, is there a way to use a readable stream as body of POST (or PUT) request, to avoid memory issues with large files?

// helpers
const createBlobFromFile = async path => new Blob([ await fs.promises.readFile(path) ]); // suboptimal

const body = new FormData();
//body.append('upload', fs.createReadStream(filePath)); // doesn't work
body.append('upload', await createBlobFromFile(filePath), 'myFile.wav' );

const response = await fetch(url, { method: 'POST', body })
const result = await response.json();
console.log( response.status, result )

Thanks

Node.js version

v18

Example code

No response

Operating system

windows/mac

Scope

code

Module and version

Not applicable.

[preveen-stack]

please check https://nodejs.org/api/fs.html#filehandlecreatereadstreamoptions

[KevinSoulat]

@preveen-stack, not sure what you meant exactly.
I tried different encoding, but it didn't work.

It's possible to use stream with http module as explained here: https://stackoverflow.com/a/64002066, but I wonder if it's possible with fetch().

[preveen-stack]

const fs = require('fs');
const fetch = require('node-fetch');

const fileStream = fs.createReadStream('/path/to/large/file.wav);

fetch('https://example.com/api', {
method: 'POST',
body: fileStream
}).then(response => {
// handle response
});

Can you check this code?

[KevinSoulat]

Hi @preveen-stack, this code doesn't work (for instance require('node-fetch') can't work since it's a pure ESM module), and my point is to use the native "fetch" module and not the tier-party module "node-fetch" to do that.

[github-actions]

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[purplesyringa]

I'm also interested in this feature. Chromium supports something similar, so this is not without a precedent.

[github-actions]

It seems there has been no activity on this issue for a while, and it is being closed in 30 days. If you believe this issue should remain open, please leave a comment.
If you need further assistance or have questions, you can also search for similar issues on Stack Overflow.
Make sure to look at the README file for the most updated links.