feat(s3store): pass the contentType or filetype metadata field to S3 if supplied

[mackinleysmith]

After this PR, if the client passes a contentType value in the metadata object, the resulting file on S3 will be created with the value passed.

This change causes tusd for Go to match the NodeJS version's behavior, discussed here: https://stackoverflow.com/questions/74148196/how-to-resolve-application-octet-stream-in-s3-using-tus-node-tusd-uppy-or-net.

[Acconut]

Thank you for the PR! tusd currently uses the filetype metadata field to set the Content-Type and Content-Disposition headers in GET responses:

tusd/pkg/handler/unrouted_handler.go

Lines 1107 to 1139 in 9d85248

	// filterContentType returns the values for the Content-Type and
	// Content-Disposition headers for a given upload. These values should be used
	// in responses for GET requests to ensure that only non-malicious file types
	// are shown directly in the browser. It will extract the file name and type
	// from the "fileame" and "filetype".
	// See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Disposition
	func filterContentType(info FileInfo) (contentType string, contentDisposition string) {
	filetype := info.MetaData["filetype"]
	if reMimeType.MatchString(filetype) {
	// If the filetype from metadata is well formed, we forward use this
	// for the Content-Type header. However, only whitelisted mime types
	// will be allowed to be shown inline in the browser
	contentType = filetype
	if _, isWhitelisted := mimeInlineBrowserWhitelist[filetype]; isWhitelisted {
	contentDisposition = "inline"
	} else {
	contentDisposition = "attachment"
	}
	} else {
	// If the filetype from the metadata is not well formed, we use a
	// default type and force the browser to download the content.
	contentType = "application/octet-stream"
	contentDisposition = "attachment"
	}
	// Add a filename to Content-Disposition if one is available in the metadata
	if filename, ok := info.MetaData["filename"]; ok {
	contentDisposition += ";filename=" + strconv.Quote(filename)
	}
	return contentType, contentDisposition
	}

The contentType field is not yet used in tusd. Although it would be handy to be compatible with tus-node-server here, I think it's more important to be consistent in tusd itself. Would you mind using the filetype metadata field for setting the Content-Type on S3 as well?

[mackinleysmith]

@Acconut absolutely!! I'll add handling for the filetype field later today. Thank you for reviewing!

[mackinleysmith]

@Acconut I have updated this PR with handling for the filetype metadata field and added another test. Thanks for the suggestion.

[Acconut]

Thanks for the update! Apologies if my comment was not clear enough but I think we should only use filetype for obtaining a media type and not use contentType at all. Compatibility with tus-node-server would be nice, but then tusd uses different metadata fields for different purposes, which is not good.

[mackinleysmith]

Ok @Acconut, while I personally would prefer that publicly posted solutions for one Tus implementation would work against them all, my preference to get something merged that handles my current need to overwrite the file in S3 post-upload is greater. I will make that adjustment so that contentType is not used.