I am writing a sails.js app. I am writing an API to accept a file and encrypt it.
var file = req.body('myFile');
var fileBuffer = convertToBuffer(file);
How do I convert a file to buffer?
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2 Answers
That looks like you've got a string which represents the body of your file.
You just have to make a new buffer with it.
var fileBuffer = Buffer.from(file)
If your encoding is NOT utf8 you can specify an alternate encoding as a second optional argument.
var fileBuffer = Buffer.from(file, 'base64')
If the file is actually on disk, this is even easier, since, by default, the fs.readFile operation returns a buffer.
fs.readFile(file, function(err, buffer){})
If you're in a real old version of node Buffer.from doesn't exist and you have to use a very memory-unsafe new constructor. Please consider upgrading your node instance to support Buffer.from
5 Comments
Chasen Bettinger
If you're just now coming to this comment, please know that
new Buffer has been deprecated in replace of Buffer.from(...). You can read more about this here: nodejs.org/api/…
tkone
@ChasenBettinger thanks for the heads up -- updated to show the proper usage of Buffer
Forbidden
Its hard to find answers for File Object, tsk tsk
Alex TechNoir
If anyone here is a frontend developer, confused with backend operations, and was looking for File Object -> Buffer, while uploading image files on server, know that on server files should be processed with library like Busboy and will become FileStreams, not File Objects. So you need to convert FileStream to Buffer - that's probably what you're looking for. I answered on this topic here: stackoverflow.com/a/77429654/10489004
Greg Wozniak
Does not work in TypeScript. Getting:
Argument of type File is not assignable to parameter of type WithImplicitCoercion<string> | { [Symbol.toPrimitive](hint: 'string'): string; }In 2024 this is what I'm doing – which makes typescript happy.
First create an ArrayBuffer from the file, then pass the ArrayBuffer to Buffer.from like so
const arrayBuffer = await file.arrayBuffer()
const buffer = Buffer.from(arrayBuffer)
