Add support for Cache-Control when posting blobs

[toncid]

There seems to be no way to set Cache-Control for a blob object. Adding support for it seems to be straightforward.

For example, put_blob_single might look like this:

headers = {
  "x-ms-blob-type": "BlockBlob",
  "Content-Length": content_size(content),
  "Content-Type": options[:content_type],
  "Cache-Control": options[:cache_control],  # <<<<< new header
  "x-ms-blob-content-md5": options[:content_md5],
  "x-ms-blob-content-disposition": options[:content_disposition],
}.merge(additional_headers(options))

We can consider extending options to allow all supported properties.

Is this something that could be considered to be added into the library?
Would my PR be an option you would consider?

[JoeDupuis]

I see there seems to be a difference between Cache-Control and x-ms-blob-cache-control.

I'll play around with this and see if there are any other missing headers to add.

In the meantime, have you tried using x-ms-blob-cache-control?

For example:

client.create_block_blob(key, content, headers: { "blob-cache-control" => "public, max-age=31536000"}) (would get converted to x-ms-blob-cache-control)

[toncid]

Ha, good catch! It works this way. I was trying without the blob- part and it obviously doesn't work. Thanks!

[JoeDupuis]

You were not wrong! Cache-Control does exists. x-ms-blob-cache-control might or might not do the same thing (they have different descriptions in the doc).

I'll play with this more and make sure that all headers can be set.

Currently, theheaders option is to set the customs x-ms header.

I'll update the doc too, it's not obvious.

That being said, I think cache_control should not be "extra headers", but a main option. Just like content_type.

Until then, you should take a look at the API documentation instead of the .net documentation to get the full list of headers here's put-block for example: https://learn.microsoft.com/en-us/rest/api/storageservices/put-block?tabs=microsoft-entra-id

[toncid]

Thanks. It is good that there is a workaround for now. I ended up writing up a custom blob uploader, but now I can revert to your lib.

As I said, if you plan to make the cache_control header as a main option, then it is probably a good opportunity to do the same for all headers that have special treatment in this API.

[dombarnes]

In the old MS gem, I'd added a monkey patch for this

module ActiveStorage
  class Service::AzureStorageService < Service
    # Monkeypatch this to include cache-control headers
    def headers_for_direct_upload(key, content_type:, checksum:, filename: nil, disposition: nil, custom_metadata: {},
                                  **)
      content_disposition = content_disposition_with(type: disposition, filename: filename) if filename

      { 'Content-Type' => content_type, 'Content-MD5' => checksum,
        'x-ms-blob-content-disposition' => content_disposition, 'x-ms-blob-type' => 'BlockBlob', 'Cache-Control' => 'max-age=86400, private', **custom_metadata_headers(custom_metadata) }
    end

    def custom_metadata_headers(metadata)
      metadata.transform_keys { |key| "x-ms-meta-#{key}" }
    end
  end
end