Class: ROM::Processor::Transformer

Inherits:
ROM::Processor show all
Includes:
Composer
Defined in:
lib/rom/processor/transformer.rb

Overview

Data mapping transformer builder using dry-transformer

This builds a transformer object that is used to map a whole relation

See Also:

Defined Under Namespace

Modules: Functions

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Composer

#compose

Methods inherited from ROM::Processor

inherited

Constructor Details

#initialize(mapper, header) ⇒ Transformer

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns a new instance of Transformer.



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# File 'lib/rom/processor/transformer.rb', line 86

def initialize(mapper, header)
  @mapper = mapper
  @header = header
  @model = header.model
  @mapping = header.mapping
  initialize_row_proc
end

Instance Attribute Details

#header ⇒ Header (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns header from a mapper.

Returns:

  • (Header) —

    header from a mapper



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# File 'lib/rom/processor/transformer.rb', line 57

def header
  @header
end

#mapper ⇒ Mapper (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns mapper that this processor belongs to.

Returns:

  • (Mapper) —

    mapper that this processor belongs to



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# File 'lib/rom/processor/transformer.rb', line 52

def mapper
  @mapper
end

#mapping ⇒ Hash (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns header's attribute mapping.

Returns:

  • (Hash) —

    header's attribute mapping



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# File 'lib/rom/processor/transformer.rb', line 67

def mapping
  @mapping
end

#model ⇒ Class (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns model class from a mapper.

Returns:

  • (Class) —

    model class from a mapper



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# File 'lib/rom/processor/transformer.rb', line 62

def model
  @model
end

#row_proc ⇒ Proc (readonly)

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns row-processing proc.

Returns:

  • (Proc) —

    row-processing proc



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# File 'lib/rom/processor/transformer.rb', line 72

def row_proc
  @row_proc
end

Class Method Details

.build(mapper, header) ⇒ Dry::Transformer::Pipe

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Build a transformer object from the header

Parameters:

Returns:

  • (Dry::Transformer::Pipe) 


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# File 'lib/rom/processor/transformer.rb', line 81

def self.build(mapper, header)
  new(mapper, header).call
end

Instance Method Details

#call ⇒ Dry::Transformer::Pipe

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Coerce mapper header to a transformer object

Returns:

  • (Dry::Transformer::Pipe) 


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# File 'lib/rom/processor/transformer.rb', line 99

def call
  compose(t(:identity)) do |ops|
    combined = header.combined
    ops << t(:combine, combined.map(&method(:combined_args))) if combined.any?
    ops << header.preprocessed.map { |attr| visit(attr, true) }
    ops << t(:map_array, row_proc) if row_proc
    ops << header.postprocessed.map { |attr| visit(attr, true) }
  end
end