Setting the delimiter parameter for Get-S3ObjectV2 should return a collection of objects

[githpuk]

Currently setting the delimiter property when calling the PowerShell cmdlet Get-S3ObjectV2 appears to have no effect and requires accessing the $AWSHistory cmdlet buffer to determine results, returned as CommonPrefixes. This makes little sense (to me anyway) when it could return a collection of the objects matching the delimiter.

Instead I propose that it return a Contents collection of objects that match the delimiter.

This would allow requesting a list of "folders" simply by setting the parameter to '/'

This would allow easy iteration through s3 folders which would both simplify and reduce the amount of PowerShell script required for, in my case, a lambda function as no access to $AWSHistory would be needed.

[ashishdhingra]

Hi @githpuk,

Thanks for submitting feature request. Could you please confirm if the Delimiter parameter is working as per requested behavior in earlier Get-S3Object CmdLet (which uses ListObjects API operation)? The new Get-S3ObjectV2 CmdLet uses ListObjectsV2 API operation which also supports Delimiter parameter. Both ListObject and ListObjectV2 API operations mention delimiter as a character you use to group keys. The way delimiter is used is controlled by the service API and modifying the default behavior could be a breaking change for existing customer.

Thanks,
Ashish

[githpuk]

Hi @ashishdhingra

Get-S3Object works the same as Get-S3ObjectV2 when it comes to delimiter behaviour. I'm not suggesting that you change existing behaviour rather enhance the PowerShell cmdlet to behave in a more typical PowerShell manner. From a PowerShell user perspective, having to access $AWSHistory to get the results of a call is atypical. Calling Get-S3Object or Get-S3ObjectV2 with the delimiter set returns $null, implying nothing matched when this is not the case as the results are within $AWSHistory.

Hope that's a bit clearer.

[jberezanski]

It seems it is possible to obtain the list of "folders", without reaching to $AWSHistory, by using -Select:

PS> Get-S3Object -BucketName my-bucket -Delimiter '/' -Select CommonPrefixes
Prefix1/
Prefix2/

However, this is certainly not intuitive. It would help if such an example was added to the documentation of Get-S3Object/Get-S3ObjectV2.

[jnunn-aws]

AWS Tools for PowerShell is designed to simplify the majority of cmdlet invocations by unwrapping AWS response objects so that the single-most pertinent property is passed to the pipeline/host. This creates edge cases where some additional properties might be discarded by default.

As Jakub pointed out, the -Select parameter is provided to override this behavior including returning the entire response object if needed. The user guide and cmdlet examples have highlighted the $AWSHistory variable as the primary workaround.

We will revise documentation to increase recommendation of the -Select parameter.