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S3 presigned URL: a private file, shared for a short time
S3 presigned URL: a private file, shared for a short time S3 is Amazon’s file storage. A bucket is a folder there. A presigned URL is a link with a time limit and a signature, so one person can open one private file . The bucket stays 100% private . Logged-in users still get their files. It works fo
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What this card says
What is it?
S3 is Amazon’s file storage. A bucket is a folder there. A presigned URL is a link with a time limit and a signature, so one person can open one private file.
Why use it
The bucket stays 100% private. Logged-in users still get their files.
It works for download (GET) and upload (PUT).
Safety rules
Anyone who has the link can use it until it expires. So keep expiry short: 10–20 minutes for videos, not 7 days.
Only make links for files that user is allowed to see.
If a user can ask for any file name, they may get someone else’s file (an IDOR bug).
Learn more in the lesson: 14.6 Presigned URLs: Temporary Private Access