是否可以生成允许上传多个唯一对象的单个预签名 URL？

Question

I know based on the AWS docs here

https://docs.aws.amazon.com/AmazonS3/latest/dev/PresignedUrlUploadObject.html

that its possible to generate a URL which can can used to

upload a specific object to your bucket

and that

You can use the presigned URL multiple times, up to the expiration date and time.

It is also possible to generate a URL (perhaps a base s3 presigned URL) which would allow multiple different unique documents to be uploaded based on a single URL?

For example, lets imagine a client application would like to upload multiple unique/distinct documents to s3 using some type of presigned URL. I dont necessarily want to force them to get a batch of presigned URLs since that would require much more on the part of the client (they would have to request batch of presigned URLs, rather than a single URL)

Here is the flow for a single document upload.

What is the simplest known solution for allowing a client to use some type of presigned url to upload multiple documents?

Answer 1

It is possible to upload multiple files with a single pre-signed URL and properly configured 'Starts-with' policy. Please, refer to the following AWS documentation: Browser-Based Uploads Using POST

Answer 2

It is also possible to generate a URL (perhaps a base s3 presigned URL) which would allow multiple different unique documents to be uploaded based on a single URL?

A presigned URL is limited to a single single object key. You can't, for example, presign a key of foo and then use it to upload foo/bar (because that's a different key).

That means that, if you want to provide the client with a single pre-signed URL, the client code will have to combine the files itself. For example, you require the client to upload a ZIP file, then trigger a Lambda that unpacks the files in that ZIP.

Another approach is to use the AWS SDK from the client, and use the Assume Role operation to generate temporary access credentials that are restricted to uploading files with a specified prefix using an inline session policy.

A third approach is to hide the URL requests. You don't say what your client application does, but assuming that you let the user select some number of files, you could simply loop over those files and retrieve a URL for each one without ever letting your user know that's happening.