Allow setting of custom metadata

I understand from the documents for cloud storage that it is possible to set custom metadata with the x-goog-meta- prefix as specified here: https://cloud.google.com/storage/docs/reference-headers#xgoogmeta

I've tried to take this approach to set custom metadata on objects created using gcloud-node as follows:

    var stream = file.createWriteStream({
      metadata: {
        'x-goog-meta-entry-type': entry.type,
      }
    });

    stream.once("finish", resolve);
    stream.once("error", reject);
    stream.end(buffer);

However, no objects created using that approach have the custom metadata reflected when requested via file.getMetadata() nor when viewed via the online storage browser.

How can one set custom metadata using gcloud-node?

Thanks for catching this! I'm talking to myself about a good solution over in #373 - feel free to chime in :)

@ggoodman

Hey @ggoodman nice issue! This raises an entirely different question as well and that is: "Do we have a way to specify custom headers?" I'm going to guess no. But I think that's okay, because doing that is beyond the scope of this library. That being said, I think we do support custom metadata already although it's poorly documented. What you need to do is a set a metadata object within your original metadata object, like so:

fs.createReadStream('/my/local/file.png')
  .pipe(image.createWriteStream({
    metadata: { 
      contentType: 'image/jpeg',
      metadata: {
        customProperty: 'my cool photo'
      }
    }
  }))
  .on('error', function(err) {});

@ggoodman

@ggoodman

Notice the docs you linked to are under the hierarchy

Cloud Storage API >XML API > API Reference > Headers and Query Parameters

So this header (I'm fairly certain) only applies to the XML API, not the JSON API.

@dhermes

@dhermes Good catch, I did not notice this either.

@dhermes

Hi @dhermes good catch. I guess I wasn't able to identify the correct api that backs this project. Perhaps that is an issue itself. I consider myself a passable code / documentation spelunker and wasn't able to track this down.

My path there was:

Have a need for custom metadata
Identify that the underlying service supports custom metadata
Search left and right for anything cloud storage and custom metadata

I think that a simple fix would be to clarify that custom metadata is settable via the metadata of the metadata in the documents. At the same time, it would be nice to describe how said custom metadata will be returned via the getMetadata() call.

Thanks for taking a look at this so quickly, @dhermes and @ryanseys.