JS 使用重定向获取 URL

Question

I have a link A that redirects to a link B which is a PHP endpoint to download a text file. I was running the following code and it was working before:

const file = await fetch(linkA).then(res => res.text())

But lately, the server for link A stopped redirecting me to link B giving CORS error. but if I copy link A and paste it on the address bar, the browser will be redirected to link B and will start downloading the file immediately. And if I just change linkA with linkB directly in the code, I can download it without any CORS error, but in the app, I will only have Link A.

So my question is : can I get the link B programmatically before fetching it?

I wished to share the links but they are private, unfortunately.

EDIT

just to give more information. Link A is like an authentication endpoint, I need to pass username and password as query parameters. So the server authenticates it and redirects me to another endpoint (I believe that it's a temporary link) with the file I want to download which I can use in the fetch method without cors error.

EDIT 2

It seems that the server of link A only redirects me if I am from the same origin, so what I believe to be possible is to create a sort of silent window that navigate to link A window.location.href and after it gets redirected, I would need to block the file to not be downloaded automatically, get the link B and fetch it in the app... but I don't have a clue how to do it.

Answer 1

This is due to linkA server may have restricted it's access to same origin only.

And, if you are using using browser, it will work as you are directly hitting the URL which is technically same origin, but when you are using ajax call you are calling it from some different origin.

If you still want to use it seriously, then you can use cors anywhere. -> https://www.npmjs.com/package/cors-anywhere