Question

I’m using ActiveRecord with Sinatra. I have AR relation Post has_many Comments.

I need to create response in JSON that returns all posts and their comments. It should look like this:

[
    { 
        "id":1,
        "title:"Title_1",
        "comments":[
            { "content":"lorem ipsum", "post_id":1 },
            { "content":"foo bar",     "post_id":1 },
        ]
    },

    { 
        "id":2,
        "title:"Title_2",
        "comments":[
            { "content":"lorem ipsum", "post_id":2 },
            { "content":"foo bar",     "post_id":2 },
        ]
    }
]

I think it common task to create response like that, so I hope there should be some nice way to do it.

My temporary solution (the code below) works correctly but it too long and unreadable:

Post.all.map{|x| x.as_json(include: [:comments]).values[0] }.to_json

This is another solution that I found:

Post.all.as_json(include: [:comments]).to_json

Sadly, the returned structure looks different, it wraps every post into additional node "post: {}". I’d like to avoid it.

[ 
     { 
          "post":{ 
              "id":1,
              "title:"Title_1",
              "comments":[
                  { "content":"lorem ipsum", "post_id":1 },
                  { "content":"foo bar",     "post_id":1 },
              ]
          }
     },

     { 
          "post":{ 
              "id":1,
              "title:"Title_2",
              "comments":[
                  { "content":"lorem ipsum", "post_id":2 },
                  { "content":"foo bar",     "post_id":2 },
              ]
          }
     }
]

Answer 1

try:

ActiveRecord::Base.include_root_in_json = false

http://apidock.com/rails/ActiveRecord/Serialization/to_json