Add convenience method for S3 presigned posts

[F21]

Is your feature request related to a problem? Please describe.
The presign client for S3 currently supports presigning GetObject and PutObject URLs: https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/service/s3#PresignClient

It would be nice if an additional method is implemented to support presigning POST object URLs documented here: https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectPOST.html

This feature seems to be present in SDKs for other languages.

Describe the solution you'd like
Add a convenience method for S3 presigned posts to the PresignClient

Describe alternatives you've considered
n/a

Additional context
n/a

[ArtemSBulgakov]

Any update on this? I am interested in this function too

[Maximilian5189]

I am interested too. It seems there were no changes requested to the PR (aws/aws-sdk-go#3287) since 2020. Does this mean the PR could be merged? What would be still missing? I would be happy to assis somehow if needed.

[soapiestwaffles]

+1, I've been waiting for this for a while. I have had to make my own in the past

[william20111]

+1, Would be very good to have this as part of SDK

[MrGossett]

Does the v4.Signer.PresignHTTP method in aws/signer/v4 get close to what you're looking for?

[william20111]

@MrGossett thanks for replying, just for my understanding. If i take the example policy from the docs of s3 POSt policy.

{ "expiration": "2007-12-01T12:00:00.000Z",
  "conditions": [
    {"acl": "public-read" },
    {"bucket": "johnsmith" },
    ["starts-with", "$key", "user/eric/"],
  ]
}

If i SHA256 that payload and provide it to the below signer I can get the same behaviour?

func main() {
	preSigner := v4.NewSigner()
	req, _ := http.NewRequest()
	preSigner.PresignHTTP(context.TODO(), creds, req, hashedPayload, s3ServiceString, regionString, time.Now())
}

[MrGossett]

@MrGossett thanks for replying,

Cheers :) Just for transparency: I don't work for AWS. I'm just a very active AWS SDK Go user.

just for my understanding. If i take the example policy from the docs of s3 POSt policy.

{ "expiration": "2007-12-01T12:00:00.000Z",

  "conditions": [

    {"acl": "public-read" },

    {"bucket": "johnsmith" },

    ["starts-with", "$key", "user/eric/"],

  ]

}

If i SHA256 that payload and provide it to the below signer I can get the same behaviour?

func main() {

	preSigner := v4.NewSigner()

	req, _ := http.NewRequest()

	preSigner.PresignHTTP(context.TODO(), creds, req, hashedPayload, s3ServiceString, regionString, time.Now())

}

No, not quite. The hashedPayload argument is a SHA sum of the HTTP request's body. I guess that method won't do what you want easily.

[vudh1]

Hi all, I have discussed with the team, and we are planning to implement this. However, there is no timeline for this yet, I will comment if we have any update.

[QuteBits]

could someone from the core team please review it (or at least assign someone to review it)? Our company is heavily using Go and unfortunately we do need presigned POST for uploads in the next 2 weeks.

If there is an implementation of that in some PR, could you perhaps point me to it?

[skmcgrail]

@QuteBits this GitHub issue is to just track the feature request, and is not a pull request for the implementation. This remains an item on our backlog, but we are unable to provide a timeline at this time on when we can pick up implementation of this feature.

[QuteBits]

@skmcgrail got it. And thank you for such a quick response.