Feature Request: Get MD5 hash from Closed ObjectCreateFile struct

[whereswaldon]

I've been writing a lot of code to build SLO manifest files from smaller chunks of data. I need the MD5 hash of each chunk for its manifest entry. Right now, even though the connection.ObjectCreate can check the MD5 hash for me, I can't get its value, so I have to redundantly compute it. I know that I can pull it down after the upload completes with connection.Object, but I'd rather not make the HTTP request. Could a method be added to the ObjectCreateFile struct that exposes the computed hash? Perhaps something like:

// Etag returns the MD5 hash of a successful upload. If it is called before
// an upload is closed or on an unsuccessful upload, it will return an error
// and an undefined byte slice.
func (file *ObjectCreateFile) Etag() ([]byte, error)

[ncw]

Seems like a sensible idea.

Perhaps more general purpose would be

// Headers returns the HTTP headers of a successful upload. If it is called before
// an upload is Close()ed or on an unsuccessful upload, it will return a nil map and an error.
func (file *ObjectCreateFile) Headers() (Headers, error)

Or possibly even better would be this as the Object has a Hash field, but is useful for other things...

// Object returns the Object for a successful upload. If it is called before
// an upload is Close()ed or on an unsuccessful upload, it will return a
// nil Object and an error.
func (file *ObjectCreateFile) Object() (*Object, error)

[whereswaldon]

I quite like the second one. How difficult would the implementation be?

[ncw]

I quite like the second one. How difficult would the implementation be?

It would be quite straight forward - fancy having a go?

[whereswaldon]

Do you have any suggestions on how to fill out the PseudoDirectory and SubDir fields on the returned Object struct from the information at hand? I can see how to get all of the other properties of the Object from the ObjectOpenFile, but not those two.

[ncw]

You can set PseudoDirectory to false and SubDir to empty string - these are only relevant when listing directory objects.