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jsonrubyobject

ArgumentError: Unknown field error Ruby JSON.parse(json_string, object_class: XYZ)

My Ruby class Routeguide::Rectangle object looks like this, (Pay attention on lo & hi variables, those are objects of class Routeguide::Point)

<Routeguide::Rectangle: lo: <Routeguide::Point: latitude: 400000000, longitude: -750000000>, hi: <Routeguide::Point: latitude: 420000000, longitude: -730000000>>`

I have correct json string for this object,

json_string = '{"lo":{"latitude":400000000,"longitude":-750000000},"hi":{"latitude":420000000,"longitude":-730000000}}'

I need to parse this json string again to create Routeguide::Rectangle class object like:

<Routeguide::Rectangle: lo: <Routeguide::Point: latitude: 400000000, longitude: -750000000>, hi: <Routeguide::Point: latitude: 420000000, longitude: -730000000>>`

I am using below code to achieve this:

JSON.parse(json_string, object_class: Routeguide::Rectangle)

But that is giving me error on JSON.parse method: #<ArgumentError: Unknown field: latitude>

Stacktrace:

[
  "/Users/psen/.rbenv/versions/2.7.7/lib/ruby/2.7.0/json/common.rb:156:in `[]='",
  "/Users/psen/.rbenv/versions/2.7.7/lib/ruby/2.7.0/json/common.rb:156:in `parse'",
  "/Users/psen/.rbenv/versions/2.7.7/lib/ruby/2.7.0/json/common.rb:156:in `parse'"
]
Solution

  • Assuming that you're also generating that json string, you could look into using JSON Additions. You'd have to define a Custom Addition to help with the serialization & deserialization.