Class: ARLoader::CsvLoader

Inherits:
LoaderBase show all
Defined in:
lib/loaders/csv_loader.rb

Instance Attribute Summary

Attributes inherited from LoaderBase

#current_method_detail, #current_value, #failed_objects, #headers, #load_object, #load_object_class, #loaded_objects, #options

Instance Method Summary collapse

Methods inherited from LoaderBase

#abort_on_failure?, #contains_mandatory?, #failed_count, #find_and_process, #find_or_new, #loaded_count, #missing_mandatory, #new_load_object, #process, #reset, #save, set_multi_assoc_delim, set_multi_value_delim, set_name_value_delim

Constructor Details

#initialize(klass, object = nil, options = {}) ⇒ CsvLoader

Returns a new instance of CsvLoader.



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# File 'lib/loaders/csv_loader.rb', line 17

def initialize(klass, object = nil, options = {})
  super( klass, object, options )
  raise "Cannot load - failed to create a #{klass}" unless @load_object
end

Instance Method Details

#load(file_name, options = {}) ⇒ Object 



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# File 'lib/loaders/csv_loader.rb', line 23

def load(file_name, options = {})

  require "csv"

  # TODO - abstract out what a 'parsed file' is - so a common object can represent excel,csv etc
  # then  we can make load() more generic
  
  @parsed_file = CSV.read(file_name)


  @headers = @parsed_file.shift

  @method_mapper = ARLoader::MethodMapper.new

  # Convert the list of headers into suitable calls on the Active Record class
  @method_mapper.populate_methods( load_object_class, @headers )

  unless(@method_mapper.missing_methods.empty?)
    puts "WARNING: Following column headings could not be mapped : #{@method_mapper.missing_methods.inspect}"
    raise MappingDefinitionError, "ERROR: Missing mappings for #{@method_mapper.missing_methods.size} column headings"
  end

  #if(options[:verbose])
  puts "\n\n\nLoading from CSV file: #{file_name}"
  puts "Processing #{@parsed_file.size} rows"
  # end

  load_object_class.transaction do
    @loaded_objects =  []

    @parsed_file.each do |row|
  
      # TODO - Smart sorting of column processing order ....
      # Does not currently ensure mandatory columns (for valid?) processed first but model needs saving
      # before associations can be processed so user should ensure mandatory columns are prior to associations

      # as part of this we also attempt to save early, for example before assigning to
      # has_and_belongs_to associations which require the load_object has an id for the join table

      # Iterate over the columns method_mapper found in Excel,
      # pulling data out of associated column
      @method_mapper.method_details.each_with_index do |method_detail, col|

        value = row[col]

        process(method_detail, value)
      end

      # TODO - handle when it's not valid ?
      # Process rest and dump out an exception list of Products ??

      puts "SAVING ROW #{row} : #{load_object.inspect}" #if options[:verbose]

      save

      # don't forget to reset the object or we'll update rather than create
      new_load_object

    end
  end

end