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Class: Mongo::Collection::View::Builder::Aggregation

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, Forwardable
Inherits: Object
Defined in: lib/mongo/collection/view/builder/aggregation.rb

Overview

Builds an aggregation command specification from the view and options.

Since:

  • 2.2.0

Constant Summary

  • MAPPINGS =

    The mappings from ruby options to the aggregation options.

    Since:

    • 2.2.0

    # File 'lib/mongo/collection/view/builder/aggregation.rb', line 32 
    BSON::Document.new(
  allow_disk_use: 'allowDiskUse',
  bypass_document_validation: 'bypassDocumentValidation',
  explain: 'explain',
  collation: 'collation',
  comment: 'comment',
  hint: 'hint',
  let: 'let',
  # This is intentional; max_await_time_ms is an alias for maxTimeMS
  # used on getMore commands for change streams.
  max_await_time_ms: 'maxTimeMS',
  max_time_ms: 'maxTimeMS',
).freeze

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(pipeline, view, options) ⇒ Aggregation

Initialize the builder.

Parameters:

  • pipeline (Array<Hash>) —

    The aggregation pipeline.

  • view (Collection::View) —

    The collection view.

  • options (Hash) —

    The map/reduce and read preference options.

Since:

  • 2.2.0

[ GitHub ] 

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 64



def initialize(pipeline, view, options)
  @pipeline = pipeline
  @view = view
  @options = options
end


  







Instance Attribute Details



  

    #options  ⇒ Hash  (readonly)
  



  

    
  





  
Returns:


    
  
  • 
    (Hash)
—    
    

    options The map/reduce specific options.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 55



attr_reader :options


  








  

    #pipeline  ⇒ Array<Hash>  (readonly)
  



  

    
  





  
Returns:


    
  
  • 
    (Array<Hash>)
—    
    

    pipeline The pipeline.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 49



attr_reader :pipeline


  








  

    #view  ⇒ Collection::View  (readonly)
  



  

    
  





  
Returns:



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 52



attr_reader :view


  








  

    #write?  ⇒ Boolean  (readonly, private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 94



def write?
  pipeline.any? do |operator|
    operator[:$out] || operator['$out'] ||
    operator[:$merge] || operator['$merge']
  end
end


  







Instance Method Details



  

    #aggregation_command   (private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 101



def aggregation_command
  command = BSON::Document.new
  # aggregate must be the first key in the command document
  if view.is_a?(Collection::View)
    command[:aggregate] = collection.name
  elsif view.is_a?(Database::View)
    command[:aggregate] = 1
  else
    raise ArgumentError, "Unknown view class: #{view}"
  end
  command[:pipeline] = pipeline
  if read_concern = view.read_concern
    command[:readConcern] = Options::Mapper.transform_values_to_strings(
      read_concern)
  end
  command[:cursor] = batch_size_doc
  command.merge!(Options::Mapper.transform_documents(options, MAPPINGS))
  command
end


  








  

    #batch_size_doc   (private)
  



  

    
  





  
Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 121



def batch_size_doc
  value = options[:batch_size] || view.batch_size
  if value == 0 && write?
    {}
  elsif value
    { :batchSize => value }
  else
    {}
  end
end


  








  

    #specification  ⇒ Hash 
  



  

    

Get the specification to pass to the aggregation operation.


  





    

    
Examples:

        


Get the specification.



      
builder.specification

  


Returns:


    
  
  • 
    (Hash)
—    
    

    The specification.
    

    
  
    • 



Since:


    
  
  • 
    
    

    2.2.0
    

    
  
    • 





  [ GitHub ]


  

  


# File 'lib/mongo/collection/view/builder/aggregation.rb', line 78



def specification
  spec = {
    selector: aggregation_command,
    db_name: database.name,
    read: @options[:read_preference] || view.read_preference,
    session: @options[:session],
    collation: @options[:collation],
  }
  if write?
    spec.update(write_concern: write_concern)
  end
  spec
end