Class: JsonDataExtractor

Inherits:
Object
  • Object
show all
Defined in:
lib/src/version.rb,
lib/json_data_extractor.rb

Constant Summary collapse

VERSION = 
'0.0.10'

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(json_data, modifiers = {}) ⇒ JsonDataExtractor

Returns a new instance of JsonDataExtractor.



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# File 'lib/json_data_extractor.rb', line 7

def initialize(json_data, modifiers = {})
  @data      = json_data.is_a?(Hash) ? json_data.to_json : json_data # hopefully it's a string; maybe we'll add some validation here
  @modifiers = modifiers.transform_keys(&:to_sym) # todo address this later
end

Instance Attribute Details

#data ⇒ Object (readonly)

Returns the value of attribute data.



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# File 'lib/json_data_extractor.rb', line 5

def data
  @data
end

#modifiers ⇒ Object (readonly)

Returns the value of attribute modifiers.



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# File 'lib/json_data_extractor.rb', line 5

def modifiers
  @modifiers
end

Instance Method Details

#add_modifier(modifier_name, &block) ⇒ Object

Parameters:

  • modifier_name (String, Symbol) 


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# File 'lib/json_data_extractor.rb', line 13

def add_modifier(modifier_name, &block)
  modifier_name            = modifier_name.to_sym unless modifier_name.is_a?(Symbol)
  modifiers[modifier_name] = block
end

#extract(schema) ⇒ Object

Parameters:

  • schema (Hash) —

    schema of the expected data mapping



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# File 'lib/json_data_extractor.rb', line 19

def extract(schema)
  results = {}
  schema.each do |key, val|
    if val.is_a?(Hash)
      val.transform_keys!(&:to_sym)
      path       = val[:path]
      modifiers  = Array(val[:modifiers] || val[:modifier]).map do |mod|
        case mod
        when Symbol, Proc
          mod
        when String
          mod.to_sym
        else
          raise ArgumentError, "Invalid modifier: #{mod.inspect}"
        end
      end
      array_type = 'array' == val[:type]
      nested     = val.dup.delete(:schema)
    else
      path      = val
      modifiers = []
    end

    extracted_data = JsonPath.on(@data, path)

    if extracted_data.empty?
      results[key] = nil
    else
      results[key] = apply_modifiers(extracted_data, modifiers)

      if array_type && nested
        results[key] = extract_nested_data(results[key], nested)
      elsif !array_type && nested
        results[key] = extract_nested_data(results[key], nested).first
      elsif !array_type && 1 < results[key].size
        # TODO: handle case where results[key] has more than one item
        # do nothing for now
      elsif array_type && !nested
        # do nothing, it is already an array
      else
        results[key] = results[key].first
      end
    end
  end
  results
end