serializable_hash vs serializable_json when rendering json

[kapso]

Whats the recommended way of using the serializer when rendering json in a controller? Is one better than the other?

class PostsController < ApplicationController
  def index
    posts = Post.joins(:comments)

    render json: PostSerializer.new(posts).serialized_json
    render json: PostSerializer.new(posts).serializable_hash # OR
    render json: PostSerializer.new(posts) # OR
  end
end

[kapso]

Looks like all 3 produce the same output, but .serialized_json is the fastest. So closing this.

[zingsurfer]

This is a good question. My mentee, @melatran, and I were discussing this, and came up with some additional thoughts on it for different use cases.

When rendering json,serializable_json and serialized_hash do appear to have the same output on an api endpoint. And importantly, the 3rd option where neither serialize method is called(json: PostSerializer.new(posts)) just returns the unserialized PostSerializer object. Otherwise, the main difference is the class of the data that's being returned and how we can interact with it.

serialized_json sends back a JSON string object. We'll need to parse it to retrieve the data we're looking for.

Or, we could use serializable_hash. This returns a Hash object that we can retrieve data from right away.

For data that we're going to use internally on our views, serializable_hash might be best. For data that we're serving up in an api endpoint that returns JSON, might as well use serialized_json.