Is it possible to upload a file in memory using javascript for processing before sending it to server?

Question

Let's say I want to use some js encryption library (not java) to encrypt a file. Is it possible to do so on client side before sending the file to the server and so upload a file by javascript in some memory on client side ?

Could I use local storage for example at least for latest browsers ?

yes you can...have a look at html5 file API!

Selvam Palanimalai
– Selvam Palanimalai

2012-07-28 12:09:15 +00:00
Commented Jul 28, 2012 at 12:09 — Selvam Palanimalai
– Selvam Palanimalai, Commented Jul 28, 2012 at 12:09

ZER0 · Accepted Answer · 2012-07-28 12:09:52Z

6

You could use the File API

Here some examples: https://developer.mozilla.org/en/Using_files_from_web_applications)

Of course, as you imagined, you need latest browsers.

answered Jul 28, 2012 at 12:09

ZER0

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1 Comment

Ruan Mendes Over a year ago

This answer should have some code showing what to do, link only answers are not as useful, I'm not sure what part of that link talks about uploading an in memory file...

Khanh Luong · Accepted Answer · 2022-09-17 05:21:26Z

Yes you can. You have a few options to do that though.

Using `FormData`

const formData = new FormData()
formData.append('file', new Blob([fileTextContent], {type: 'text/plain'}))
await axios.post('/upload-file', formData)

Documentation: https://developer.mozilla.org/en-US/docs/Web/API/FormData/Using_FormData_Objects#creating_a_formdata_object_from_scratch

Set a file `<input>`'s value

let file = new File([data], "img.jpg",{type:"image/jpeg", lastModified:new Date().getTime()});
let container = new DataTransfer();
container.items.add(file);
fileInputElement.files = container.files;

Then you can submit the form containing the <input> normally.

The code above is from this SO answer: https://stackoverflow.com/a/66466855/14366961

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Is it possible to upload a file in memory using javascript for processing before sending it to server?

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Using `FormData`

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