Class: Serialism::Collection

Inherits:
Object
  • Object
show all
Defined in:
lib/serialism/collection.rb

Overview

Combines a set of items and a serializer class.

Example:

class Foo
  attr_accessor :id
end

class FooSerializer < Serialism::Serializer
  attributes :id
end

Serialism::Collection.new(a_bunch_of_foo_instances, serializer: FooSerializer).to_csv
#=> returns a CSV string

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(items = [], serializer:) ⇒ Collection

create a new collection

Parameters:

  • items (Enumerable) (defaults to: []) —

    A collection of items. All member items should be encodable by ‘serializer`.

  • serializer (Serialism::Serializer) —

    The serializer class used to encode members of ‘items`.



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# File 'lib/serialism/collection.rb', line 26

def initialize(items = [], serializer:)
  if !serializer.respond_to?(:attributes)
    raise ArgumentError, 'serializer must implement a class-level :attributes method'
  end
  if !serializer.instance_methods.include?(:render)
    raise ArgumentError, 'serializer must implement an instance-level :render method'
  end
  @serializer = serializer

  self.items = items
end

Instance Attribute Details

#items ⇒ Object

Returns the value of attribute items.



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# File 'lib/serialism/collection.rb', line 17

def items
  @items
end

Instance Method Details

#attributes ⇒ Array

return the attributes for the collection

Returns:

  • (Array) 


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# File 'lib/serialism/collection.rb', line 55

def attributes
  return [] if items.empty?

  @serializer.attributes
end

#to_a ⇒ Object

this generates an array of arrays headers are [0] data starts at [1]



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# File 'lib/serialism/collection.rb', line 87

def to_a
  [attributes] + items.map { |i| render_row(i) }
end

#to_csv ⇒ String

Generate a csv string for the collection

When members of the array returned by the serializer are themselves arrays, these sub-arrays will be joined using “,” prior to being added to the main CSV.

Returns:

  • (String) 


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# File 'lib/serialism/collection.rb', line 68

def to_csv
  require 'csv'

  CSV.generate do |csv|
    csv << attributes
    items.map do |i|
      csv << render_row(i)
    end
  end
end

#to_json ⇒ Object 



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# File 'lib/serialism/collection.rb', line 79

def to_json
  require 'json'

  JSON.dump(items.map { |t| @serializer.new(t).render })
end