Cannot Marshal with top-level Meta

[ussu]

Hi!

I could not find a way to easily to return a response with top-level custom metadata, i.e.

{
  "data": ...
  "meta": "my data"
}

but only found a way to add metadata at the resource level, e.g.

{
  "data": [
    {
      "meta": ...
    }
  ]
}

I had to write the following helper function to achieve it. is there a better way?

import (
	"encoding/json"
	"github.com/manyminds/api2go/jsonapi"
)

func MarshalWithMeta(data interface{}, meta map[string]interface{}) ([]byte, error) {
	document, err := jsonapi.MarshalToStruct(data, nil)
	if err != nil {
		return nil, err
	}

	document.Meta = meta
	bytesResponse, err := json.Marshal(document)
	if err != nil {
		return nil, err
	}

	return bytesResponse, nil
}

[irubnich]

I found this interface you can implement in the docs: https://pkg.go.dev/github.com/manyminds/api2go/jsonapi#MarshalMeta

So you can do it like this:

type Book struct {
  Id string
}

func (b Book) Meta() jsonapi.Meta {
  return jsonapi.Meta{
    "key": "value"
  }
}

and an instance will marshal into:

{
  "data": {
    "meta": {
      "key": "value"
    },
    "attributes": {
      "Id": "1"
    }
  }
}