add to existing object in json array Rails 3 -

  render :json mailbox.inbox.as_json(:include => [       {:messages => {:only => [:body]}},        {:recipients => {:only => [:firstname,:surname]}}     ]) 

produces following output rails controller:

[     {         "conversation":         {             "subject":"subject conversation 2",             "messages" :[                 {"body":"message 1"},                 {"body":"message 2"}              ],             "recipients": [                 {"firstname":"james","surname":"smith"},                 {"firstname":"john","surname":"doe"}              ]         }     } ] 

what add current_user key:value pair each conversation object out sample this:

[     {         "conversation":         {             "subject":"subject conversation 2",             "messages" :[                 {"body":"message 1"},                 {"body":"message 2"},              ],             "recipients": [                 {"firstname":"james","surname":"smith"},                 {"firstname":"john","surname":"doe"}              ],             "current_user" :[                 {"id":10}             ]         }     } ] 

i don't have access conversation model in question (it's running off mailboxer gem) can't override as_json. appreciated

so, formalizing comments.

by looking apidock of json_as, can see way include arbitrary data add method retunrs data want use in model.

since not best thing in many ways , don't have access model, 1 way out customize json using popular gem called jbuilder, allows create more complex json.