Module: NdrImport::UniversalImporterHelper

Defined in:
lib/ndr_import/universal_importer_helper.rb

Overview

This mixin provides file importer helper methods that abstract away some of the complexity of enumerating over files and tables (which should be universally useful). It is assumed that the host module/class defines ‘unzip_path`.

Defined Under Namespace

Classes: TableEnumProxy

Instance Method Summary collapse

Instance Method Details

#extract(source_file, &block) ⇒ Object

Iterate through the file(s) line by line, yielding each one in turn, using get_table_mapping to select the mapping relevant to this file.



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# File 'lib/ndr_import/universal_importer_helper.rb', line 49

def extract(source_file, &block)
  return enum_for(:extract, source_file) unless block

  files = NdrImport::File::Registry.files(source_file,
                                          'unzip_path' => unzip_path)
  files.each do |filename|
    # now at the individual file level, can we find the table mapping?
    table_mapping = get_table_mapping(filename, nil)

    options = {
      'unzip_path'       => unzip_path,
      'col_sep'          => table_mapping.try(:delimiter),
      'file_password'    => table_mapping.try(:file_password),
      'liberal_parsing'  => table_mapping.try(:liberal_parsing),
      'xml_record_xpath' => table_mapping.try(:xml_record_xpath),
      'slurp'            => table_mapping.try(:slurp)
    }

    tables = NdrImport::File::Registry.tables(filename, table_mapping.try(:format), options)
    yield_tables_and_their_content(filename, tables, &block)
  end
end

#get_notifier(_total_records) ⇒ Object

This method needs to be implemented where this mixin is used.

Raises:

  • (NotImplementedError) 


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# File 'lib/ndr_import/universal_importer_helper.rb', line 92

def get_notifier(_total_records)
  raise NotImplementedError, 'get_notifier must be defined!'
end

#get_table_mapping(filename, tablename) ⇒ Object

This method returns the correct NdrImport::,NonTabular::Table for the given filename/tablename. It requires all the mappings to be stored in the table_mappings instance variable.



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# File 'lib/ndr_import/universal_importer_helper.rb', line 43

def get_table_mapping(filename, tablename)
  @table_mappings.find { |mapping| mapping.match(filename, tablename) }
end

#mapped_tables(filename) ⇒ Object 



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# File 'lib/ndr_import/universal_importer_helper.rb', line 87

def mapped_tables(filename)
  @mapped_tables ||= table_enumerators(filename)
end

#record_total(filename, table_content) ⇒ Object 



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# File 'lib/ndr_import/universal_importer_helper.rb', line 96

def record_total(filename, table_content)
  if '.csv' == ::File.extname(filename).downcase
    return `wc -l #{Shellwords.escape(filename)}`.strip.match(/\A(\d+)/)[1].to_i
  elsif table_content.is_a?(Enumerator)
    nil # Avoid slurping
  else
    table_content.size
  end
end

#table_enumerators(filename) ⇒ Object 



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# File 'lib/ndr_import/universal_importer_helper.rb', line 29

def table_enumerators(filename)
  table_enumerators = {}
  table_enumerators = Hash.new { |hash, key| hash[key] = TableEnumProxy.new }

  extract(filename).each do |table, rows|
    table_enumerators[table.canonical_name].add_table_enum table.transform(rows)
  end

  table_enumerators
end

#yield_tables_and_their_content(filename, tables, &block) ⇒ Object

This method does the table row yielding for the extract method, setting the notifier so that we can monitor progress



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# File 'lib/ndr_import/universal_importer_helper.rb', line 74

def yield_tables_and_their_content(filename, tables, &block)
  return enum_for(:yield_tables_and_their_content, filename, tables) unless block_given?

  tables.each do |tablename, table_content|
    mapping = get_table_mapping(filename, tablename)
    next if mapping.nil?

    mapping.notifier = get_notifier(record_total(filename, table_content))

    yield(mapping, table_content)
  end
end