lib/grape/validations/types/json.rb
# frozen_string_literal: true
module Grape
module Validations
module Types
# Handles coercion and type checking for parameters that are complex
# types given as JSON-encoded strings. It accepts both JSON objects
# and arrays of objects, and will coerce the input to a +Hash+
# or +Array+ object respectively. In either case the Grape
# validation system will apply nested validation rules to
# all returned objects.
class Json
class << self
# Coerce the input into a JSON-like data structure.
#
# @param input [String] a JSON-encoded parameter value
# @return [Hash,Array<Hash>,nil]
def parse(input)
return input if parsed?(input)
# Allow nulls and blank strings
return if input.nil? || input.match?(/^\s*$/)
JSON.parse(input, symbolize_names: true)
end
# Checks that the input was parsed successfully
# and isn't something odd such as an array of primitives.
#
# @param value [Object] result of {#parse}
# @return [true,false]
def parsed?(value)
value.is_a?(::Hash) || coerced_collection?(value)
end
protected
# Is the value an array of JSON-like objects?
#
# @param value [Object] result of {#parse}
# @return [true,false]
def coerced_collection?(value)
value.is_a?(::Array) && value.all?(::Hash)
end
end
end
# Specialization of the {Json} attribute that is guaranteed
# to return an array of objects. Accepts both JSON-encoded
# objects and arrays of objects, but wraps single objects
# in an Array.
class JsonArray < Json
class << self
# See {Json#parse}. Wraps single objects in an array.
#
# @param input [String] JSON-encoded parameter value
# @return [Array<Hash>]
def parse(input)
json = super
Array.wrap(json) unless json.nil?
end
# See {Json#coerced_collection?}
def parsed?(value)
coerced_collection? value
end
end
end
end
end
end