Active Model Serializer and multiple meta values - ruby-on-rails-3

Question

I am looking at the README for Active Model Serializer and see this example:
render json: #posts, serializer: CustomArraySerializer, meta: {total: 10}, meta_key: 'meta_object'
...
{
"meta_object": { "total": 10 },
"posts": [
{ "title": "Post 1", "body": "Hello!" },
{ "title": "Post 2", "body": "Goodbye!" }
]
}
but I'd like to be able to output:
{
"meta_object": { "total": 10 },
"sort":[2,1],
"posts": [
{ "title": "Post 1", "body": "Hello!" },
{ "title": "Post 2", "body": "Goodbye!" }
]
}
I'm guessing I need to have two meta objects. Is this possible? How would I do it?

Answer 1

The normal solution would be to nest the "sort" key itself under the "meta" key ("meta" is the catch-all place for response info that is not a model). So you would use:
render json: #posts, serializer: CustomArraySerializer, meta: { total: 10, sort: [2, 1] }, meta_key: 'meta_object'
...
{
"meta_object": {
"total": 10,
"sort": [2, 1]
},
"posts": [
{ "title": "Post 1", "body": "Hello!" },
{ "title": "Post 2", "body": "Goodbye!" }
]
}
If your requirements absolutely need the "sort" key to appear at the root, you can do it manually:
response_json = CustomArraySerializer.new(#posts).as_json.merge { sort: [2, 1] }
render json: response_json, meta: { total: 10 }, meta_key: 'meta_object'
...
{
"meta_object": {
"total": 10
},
"sort": [2, 1],
"posts": [
{ "title": "Post 1", "body": "Hello!" },
{ "title": "Post 2", "body": "Goodbye!" }
]
}