Amazon Presigner

[oharaandrew314]

It would be nice to have some sort of amazon presigner; particularly for S3 GET and PUT.

[daviddenton]

It's very possible - I'm sure we've done it before as a filter and using the signing we've already got in the Aws module of the core.

[oharaandrew314]

It seems to me the biggest/only difference between a signed request and pre-signed request is that in a pre-signed request you can customize the validity duration of the signature. If I can find the documentation (or reverse-engineer one of the SDKs) I should be able to come up with an extension to the AwsSignatureV4Signer to add the additional properties.

[oharaandrew314]

I think all I need to do is add the X-Amz-Expires header to the canonical request, and the AwsSignatureV4Signer should work out of the box.

[oharaandrew314]

I'm tantalizingly close. I'm no longer getting SignatureDoesNotMatch, but now I'm getting AccessDenied, which is frustratingly vague.

[oharaandrew314]

Bingo. I've made a PR in the main http4k repo to add a common pre-signer.

[daviddenton]

Closing as releasing in main http4k-aws module

[oharaandrew314]

I was going to make an additional helper in this repo, but now that it's possible with the main module, you can close this if you want.

[daviddenton]

Intersting - how did you envisage that helper being used?

[oharaandrew314]

Something like

fun S3Bucket.presign(action: S3BucketAction<*>): PresignedRequest

so you could do

val s3Bucket = S3Bucket.Http("foo", "ca-central-1")
val signed = s3Bucket.presign(GetObject("foo.txt"))

[daviddenton]

ok - sounds good. If you can do it I'll hold off on the connect release until it's donr

[oharaandrew314]

Timing for me will be tight, but I'll try to have it done by your next morning. If not, I'll be AFK for a week, so you should release without it.

[daviddenton]

don;t worry actually - there's nothing else to go in so will hold off :)

[oharaandrew314]

This now depends on https://github.com/http4k/http4k/pull/1015

[daviddenton]

we're now running with that latest http4k which has that change in it you need 😄

[daviddenton]

Merged and awaiting release.