JSON include syntax

Question

My setup: Rails 2.3.10, Ruby 1.8.7

I have a rather complicated set of relationships between several models.

class A
  has_many :classB
  has_many :classD
end

class B
  belongs_to :classA
  has_many :classC
end

class C
  belongs_to :classB
  belongs_to :classE
end

class D
  belongs_to :classA
  belongs_to :classE
end

class E
  has_many :classD
  has_many :classC
end

I'm having an issue with the JSON syntax to get all the related information starting with classA. Here's what I have working so far.

classA.to_json(:include => {:classB => {:include => [:classC, :classE]}})

I can't get the syntax working to also include classD and related classE records.

UPDATE Actually something like this might work except that I can't mix hashes and arrays

classA.to_json(:include => [ :classB => { :include => { :classC => { :include => :classE } } },
                             :classD, :classE  ])

Note that I didn't use singular/plural in my example code above but in my real code, I am. Any insights will be much appreciated.

Thanks, Bob

I assume classA is an object of class A?

iconoclast
– iconoclast

2013-12-23 15:26:28 +00:00
Commented Dec 23, 2013 at 15:26 — iconoclast
– iconoclast, Commented Dec 23, 2013 at 15:26

tokland · Accepted Answer · 2012-06-02 12:46:20Z

13

This should work:

classA.to_json(:include => {
  :classB => {:include => {:classC => {:include => :classE}}},
  :classD => {},
  :classE => {},
})

edited Jun 2, 2012 at 12:46

answered Feb 14, 2011 at 13:10

tokland

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2 Comments

Bob Over a year ago

Yep, that worked, I came to the same conclusion myself, tricky little syntax bugger.

Parrots Over a year ago

Have an up vote - adding => {} seems to be required when you have multiple relationships at a level, and at least one of which has a sub-include on it

Ryan Bigg · Accepted Answer · 2011-01-11 03:41:55Z

1

Try this, you should only need one :include =>:

classA.to_json(:include => {:classB => [:classC, { :classE => :classD }] })

answered Jan 11, 2011 at 3:41

Ryan Bigg

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Comments

DanneManne · Accepted Answer · 2011-01-17 04:35:49Z

1

I don't know if you want classE included through both class C and classD but this should work:

classA.to_json(:include => { :classB => { :include => { :classC => { :include => :classE } } },
                             :classD => { :include => :classE } })

EDIT:

class A
  has_many :bs
  has_many :ds
end

class B
  belongs_to :a
  has_many :cs
end

class C
  belongs_to :b
  belongs_to :e
end

class D
  belongs_to :a
  belongs_to :e
end

class E
  has_many :ds
  has_many :cs
end

@class_a = A.first
@class_a.to_json(:include => { :bs => { :include => { :cs => { :include => :e } } },
                               :ds => { :include => :e } })

edited Jan 17, 2011 at 4:35

answered Jan 11, 2011 at 3:32

DanneManne

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6 Comments

Bob Over a year ago

I have tried this before and it throws this nondescript error "undefined method `macro' for nil:NilClass"

DanneManne Over a year ago

Okay, then just to make sure, I assume that classA is not actually the model but an instance of classA, right? And after that, I'd check on your associations cause in your example you mix belongs_to and has_many, but the association is just named classA for example. Just make sure you use matching singular / plural syntax in your associations and to_json.

Bob Over a year ago

You are right, classA in the JSON line is an instance and I'm not using the proper singular / plural syntax above but in my code, I am. The :include code should all be plurals.

DanneManne Over a year ago

Except for classE which is only associated through belongs_to :classE Sorry, I can't say for sure unless you post your actual code. I have tried my syntax with a similar setup in my own project and it works for me.

Bob Over a year ago

Not sure what you mean by "classE which is only associated through belongs_to :classE"? Based on your example, I have updated my question with something that might work but not quite.

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