Support non-slash-ending prefixes in S3 Transfer

[alex-at-cascade]

This code:

aws-sdk-php/src/S3/Transfer.php

Line 238 in 7c00779

. (isset($parts['Key']) ? $parts['Key'] . '/' : '');

assumes that the S3 key prefix will be a full "path like component" for downloads, and forces it to end in a slash. However, in our use case the prefix is just the common starting part of the name for several objects that we want to download all at once. (We're encountering this as we update some old code from sdk v2 to sdk v3.)

[diehlaws]

Hi @alex-at-cascade, thanks for reaching out to us. The S3 Transfer Manager in the AWS SDK for PHP is used to upload entire directories to an Amazon S3 bucket and download entire buckets/directories to a local directory. Unfortunately your suggestion would be a breaking change for the SDK so we will not be implementing it for the current major version.

If the objects you are looking to download exist within the same S3 prefix in your Bucket you can instead issue a ListObjects call with the string matching the common starting portion of the file names as the 'Prefix' parameter for the call, and iterate through the 'Contents' portion of its response to download the desired objects from S3.

[alex-at-cascade]

Thanks for your response and suggestions. I understand that's a very common use case, to download entire "directories", assuming slash as a path separator. (Although, to be honest, I couldn't find any documentation of that limitation. I had been assuming normal S3 conventions, as is also followed by V2 of the SDK.) It's very close to being able to support everything the standard S3 API can, other than the extraneous assumed path separator. Just curious, would it be feasible to add an option in the $options array to leave the prefix as just a prefix (without mangling it)?