Class: DataTranslation

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

Overview

Simple class to provide an easy way to map and transform data.

Example Usage

agent = DataTranslation.new do |m|

m.option :strict, true

m.set  'source_id', 1

m.link 'login', 'Username'
m.link 'first_name', 'FirstName'
m.link 'last_name', 'LastName'
m.link 'phone_number', lambda {|source| "(#{source['Area']}) #{source['Phone']}"}

m.processor do |values|
  Agent.(values['source_id'], values['login'])
end

end

source = => ‘spatterson’,

'FirstName' => 'Scott',
'LastName'  => 'Patterson',
'Area'      => '123',
'Phone'     => '456-7890'

results = agent.transform(source)

puts results.inspect # => {“phone_number” => “(123) 456-7890”,

#     "last_name"    => "Patterson",
#     "login"        => "spatterson",
#     "first_name"   => "Scott"
#     "source_id"    => 1}

new_object = agent.from_source(source)

Defined Under Namespace

Modules: Destination Classes: NonresponsiveSource

Constant Summary collapse

VERSION = 
'1.1.0'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize {|_self| ... } ⇒ DataTranslation

Constructor, yields self to allow for block-based configuration.

Defaults: strict = true

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/data_translation.rb', line 56

def initialize # yields self
  @mappings      = {}
  @static_values = {}
  @options       = {:strict => true}
  @processor     = nil

  yield self if block_given?
end

Instance Attribute Details

#mappings ⇒ Object (readonly)

Returns the value of attribute mappings.



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# File 'lib/data_translation.rb', line 39

def mappings
  @mappings
end

#options ⇒ Object (readonly)

Returns the value of attribute options.



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# File 'lib/data_translation.rb', line 39

def options
  @options
end

#static_values ⇒ Object (readonly)

Returns the value of attribute static_values.



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# File 'lib/data_translation.rb', line 39

def static_values
  @static_values
end

Class Method Details

.destination(klass, name = nil) ⇒ Object

Includes DataTranslation::Destination in the specified class (klass). If a name is given, yields and returns a DataTranslation for that name. i.e. DataTranslation.destination(PlainClass, :source_name) {|dtm| dtm.link …}



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# File 'lib/data_translation.rb', line 44

def self.destination(klass, name = nil)
  # No need to include ourself again if we've already extended the class
  klass.class_eval("include(Destination)") unless klass.include?(Destination)

  if name
    klass.data_translation_map(name) {|dtm| yield dtm} if block_given?
    klass.data_translation_map(name)
  end
end

Instance Method Details

#from_source(source, options = {}) ⇒ Object

Given a source object, returns the results of #transform if no processor is defined or the results of calling the processor block as defined by #processor.



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# File 'lib/data_translation.rb', line 126

def from_source(source, options = {})
  results = transform(source, options)

  if @processor
    if @processor.arity == 1
      @processor.call(results)
    else
      @processor.call(results, source)
    end
  else
    results
  end
end

#link(to, from = nil, &block) ⇒ Object

Links a destination field to a source method, element, or lambda. to may be a string, symbol, or any object that can be used as a hash key. If from is a lambda, called with one argument (the source passed to #transform). Alternatively, can be called with a block instead of a lambda or from.

link ‘field_name’, ‘FieldName’ link :field_name, ‘FieldName’ link :field_name, lambda {|source| source…} link(:field_name) {|source| source…}



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# File 'lib/data_translation.rb', line 92

def link(to, from = nil, &block)
  @mappings[to] = block.nil? ? from : block
end

#option(name, value) ⇒ Object

Sets the option with name to value. Current options are:

:strict = boolean; true will raise a NonresponsiveSource exception if the source
                   object does not respond to a mapping.
                   false ignores non-existant fields in the source object.



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# File 'lib/data_translation.rb', line 70

def option(name, value)
  @options[name.to_sym] = value
end

#processor(&block) ⇒ Object

If called without a block, returns the current block. If called with a block, sets the block that will be run with the results from #transform when #from_source is called. The results of the transformation will be passed if the block expects only one parameter. If the block expects two parameters both the results and the original source object will be provided.



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# File 'lib/data_translation.rb', line 101

def processor(&block) # |transform_results [, source_data]|
  if block_given?
    @processor = block
  else
    @processor
  end
end

#remove_processor ⇒ Object

Removes the currently defined processor, if any.



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# File 'lib/data_translation.rb', line 110

def remove_processor
  @processor = nil
end

#set(to, value) ⇒ Object

Sets a specified to field to value during transformation without regard to the source object. If you wish to link to source object data or use a lambda/block, use #link instead. to may be any object that can be stored as a Hash key.

set :field_name, ‘Static value’



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# File 'lib/data_translation.rb', line 79

def set(to, value)
  @static_values[to] = value
end

#transform(source, options = {}) ⇒ Object

Given a source object, returns a new hash with elements as determined by the current mapping. Mapping is set by one or more calls to #link. Options passed to this method override the instance options. See #option for a list of options. #link values will override #set values.



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# File 'lib/data_translation.rb', line 118

def transform(source, options = {})
  options = @options.merge(options)

  apply_static_values(options).merge(apply_mappings(source, options))
end

#update {|_self| ... } ⇒ Object

Yields the mapping object so that options and links can be applied within a block.

Yields:

  • (_self)

Yield Parameters:



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# File 'lib/data_translation.rb', line 141

def update # yields self
  yield self
end