Storing Stringified JSON in Postgres with Rails 5 - ruby-on-rails

Question

We are upgrading our application from Rails 4.2 to Rails 5.0.
We have found that identical requests are generating different sql when inserting in to the database. The database column is JSON and it looks like in Rails 5.0 it is being stored as an escaped string.
Does anyone know how we can ensure the same behaviour between versions?
Request Params:
Parameters: {"provider_package_item"=>{"provider_package_id"=>"2", "service_id"=>"6", "service_product_id"=>"17", "provider_price_list_id"=>"12", "provider_price_list_item_id"=>"122", "options"=>"[{\"id\":95,\"title\":\"Finish\",\"value\":{\"id\":\"130\",\"title\":\"Satin\",\"price\":0}},{\"id\":96,\"title\":\"Paper Weight\",\"value\":{\"id\":\"135\",\"title\":\"200GSM\",\"price\":0}},{\"id\":112,\"title\":\"Delivery\",\"value\":{\"id\":\"189\",\"title\":\"Next Day\",\"price\":0}}]"}}
Database Query in Rails 4.2:
INSERT INTO "provider_package_items" ("provider_package_id", "service_id", "service_product_id", "provider_price_list_id", "provider_price_list_item_id", "options", "title", "quantity", "price", "options_string", "created_at", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) RETURNING "id" [["provider_package_id", 2], ["service_id", 6], ["service_product_id", 17], ["provider_price_list_id", 12], ["provider_price_list_item_id", 122], ["options", "[{\"id\":95,\"title\":\"Finish\",\"value\":{\"id\":\"130\",\"title\":\"Satin\",\"price\":0}},{\"id\":96,\"title\":\"Paper Weight\",\"value\":{\"id\":\"135\",\"title\":\"200GSM\",\"price\":0}},{\"id\":112,\"title\":\"Delivery\",\"value\":{\"id\":\"189\",\"title\":\"Next Day\",\"price\":0}}]"], ["title", "A4 Brochures"], ["quantity", 50], ["price", 65.0], ["options_string", "/Satin/200GSM/Next Day"], ["created_at", "2017-03-03 05:36:51.613297"], ["updated_at", "2017-03-03 05:36:51.613297"]]
Database Query in Rails 5.0
INSERT INTO "provider_package_items" ("title", "service_id", "service_product_id", "provider_price_list_id", "provider_price_list_item_id", "quantity", "options", "options_string", "created_at", "updated_at", "provider_package_id", "price") VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12) RETURNING "id" [["title", "A4 Brochures"], ["service_id", 6], ["service_product_id", 17], ["provider_price_list_id", 12], ["provider_price_list_item_id", 122], ["quantity", 50], ["options", "\"[{\\"id\\":95,\\"title\\":\\"Finish\\",\\"value\\":{\\"id\\":\\"130\\",\\"title\\":\\"Satin\\",\\"price\\":0}},{\\"id\\":96,\\"title\\":\\"Paper Weight\\",\\"value\\":{\\"id\\":\\"135\\",\\"title\\":\\"200GSM\\",\\"price\\":0}},{\\"id\\":112,\\"title\\":\\"Delivery\\",\\"value\\":{\\"id\\":\\"189\\",\\"title\\":\\"Next Day\\",\\"price\\":0}}]\""], ["options_string", "/Satin/200GSM/Next Day"], ["created_at", 2017-03-03 05:30:02 UTC], ["updated_at", 2017-03-03 05:30:02 UTC], ["provider_package_id", 2], ["price", 65.0]]

Answer 1

Rails 5 has been updated to comply with RFC 7159. JSON strings e.g. JSON.stringify() from Javascript are now saved as strings rather than a Hash/Array. To maintain the behaviour from previous versions of Rails you need to parse the JSON string before assigning:
Model.payload = JSON.parse("{\"key\":\"value\"}")
Or you can override the setter method in the model:
def payload=(value)
self[:payload] = value.is_a?(String) ? JSON.parse(value) : value
end

Answer 2

In https://github.com/rails/rails/issues/28292
Observations from kengreeff
In Console (Rails 4.2.2)
item = OrderItem.new(options: "{\"key\":\"value\"}")
=> #<OrderItem id: nil, options: {"key"=>"value"}>
item.options
=> {"key"=>"value"}
item.options.is_a?(String)
=> false
item.options.is_a?(Hash)
=> true
In Console (Rails 5.0.2)
item = OrderItem.new(options: "{\"key\":\"value\"}")
=> #<OrderItem id: nil, options: "{\"key\":\"value\"}">
item.options
=> "{\"key\":\"value\"}"
item.options.is_a?(String)
=> true
item.options.is_a?(Hash)
=> false
kamipo have mentioned this
rails 5
This behavior is because efaa6e4 to fix the issue #24234.
Please use
OrderItem.new(options: JSON.parse("{\"key\":\"value\"}")).