How to append a specific file to FormData with Javascript?

Question

I need to append a specific file to my FormData object using JavaScript.

var form = new FormData();
form.append("input", '{ ... some json ... }');
form.append("files", "/C:/My/Path/File.txt");

I dont want to select the file through a input button.

All examples that i founded do this:

var form = new FormData();
form.append("input", '{ ... some json ... }');
form.append("files", input.Files[0], "/C:/My/Path/File.txt");

So i think that i have to load that file into a blob or file object. But i dont get it.

Hoy can i do it? Thanks!

i think that way.. var blob = new Blob([content], { type: "text/xml"}); formData.append("webmasterfile", blob); you can check docs here developer.mozilla.org/en-US/docs/Web/API/FormData/append — Danilo Mercado Oudalova
– Danilo Mercado Oudalova, Commented Oct 18, 2021 at 23:35
"I dont want to select the file through a input button.": So you're asking the user to trust you to not upload anything else from their computer. There has to be some user interaction for security purposes. — Andy
– Andy, Commented Oct 18, 2021 at 23:43
To be clear: you cannot do this. A website could grab arbitrary files from the user's hard drive this way. — user5734311
– user5734311, Commented Oct 18, 2021 at 23:45
I understand the security issues. I need to automate an api call. If i cant do this, should i try another language? — Gonzalo Bustamante
– Gonzalo Bustamante, Commented Oct 18, 2021 at 23:50
The language doesn't matter. The browser won't allow you to load a file from a local system without user authorisation. — Andy
– Andy, Commented Oct 18, 2021 at 23:54

Gonzalo Bustamante · Accepted Answer · 2021-10-27 20:40:07Z

1

Acoording to @Andy comment and to this post https://stackoverflow.com/a/3014623/8037813, effectively it is not possible to do this by security issues.

Dont lose your time trying to do it.

Thanks.

answered Oct 27, 2021 at 20:40

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