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‫So, now, let's talk about

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‫Amazon S3 pre-signed URLs.

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‫So, they are URLs you can generate using the S3 console,

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‫the CLI or the SDK, and the URL has an expiration.

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‫So if you use the console, it's up to 12 hours

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‫and if use the CLI, you can go up to 168 hours.

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‫So, the idea is that when you generate a pre-signed URL,

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‫the user that will get that URL will inherit the permissions

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‫of the user that generated that URL for a GET or a PUT.

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‫So what's the use case?

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‫Well, say you have an S3 bucket and it's private,

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‫and you want to give someone outside of AWS

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‫access to one file.

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‫You don't want to make that file public.

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‫You don't want to make that file in any way

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‫that would break your security, right?

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‫So, you as your bucket owner or the user,

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‫you're going to generate a pre-signed URL out of this file,

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‫and the S3 Bucket will give you a URL.

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‫That URL is going to be pre-signed,

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‫meaning that it will carry over your credentials,

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‫in terms of authorization to access that file.

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‫Then you will send this URL to the target user

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‫that you want to give access to the file

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‫for a limited amount of time.

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‫And then that user, sorry,

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‫will be using the URL to access the file

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‫on the S3 Buckets.

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‫And then you will get a file back from the S3 buckets,

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‫and the user has being able to download it, for example.

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‫So, pre-signed URL are a very, very common use case

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‫when it comes to temporary access to one specific file

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‫for download or even for upload.

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‫So, the examples are to only allow logged-in users

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‫to download a premium video of your S3 bucket

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‫or to allow an ever-changing list of users

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‫to download files by generating URLs dynamically,

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‫or to allow, temporarily, a user to upload a file

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‫to a precise location in your S3 bucket,

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‫while maintaining your S3 bucket private.

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‫So that's it for this lecture,

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‫and I will see you in the next lecture for some hands on.