Data List Converter

Data List Converter is a tool to convert data between different formats.

Example:

data = [{name: 'James', age: '22'}, {name: 'Bob', age: '33'}]
DataListConverter.convert(:item_data, :table_data, data)
# => [["name", "age"], ["James", "22"], ["Bob", "33"]] 
DataListConverter.convert(:item_data, :csv_file, data, csv_file: {filename: 'result.csv'})
DataListConverter.convert(:item_data, :xls_file, data, csv_file: {filename: 'result.csv'})

DataListConverter.convert(:csv_file, :item_data, {filename: 'result.csv'}) == data

You can also add filter to this process:

filter = :limit
filter = {limit: {size: 2}}
filter = [{limit: {size: 12}}, {count: {size: 4}}]
convert(:item_iterator, :table_data, iter, table_iterator: {filter: filter})

Please read the source code for more information, also you can check test examples.

Data Types

• item_data like: [{name: 'James', age: '22'}, ...]
• item_iterator iterator for item_data, used like: iter.call{|item| out << item}
• table_data like: [["name", "age"], ["James", "22"], ["Bob", "33"], ...]
• table_iterator iterator for table_data
• csv_file file in csv format
• xls_file file in excel format
• multi_sheet_data like: {'sheet1' => [columns, row, row, ...], 'sheet2' => [columns, row, row, ...]}
• multi_sheet_iterator like: {'sheet1' => table_iterator1, 'sheet2' => table_iterator2}
• records ActiveRecord records, usage: DataListConverter.convert(:records, :item_data, query, item_iterator: {columns: [:name, :age]})

Filters

item_iterator/table_iterator limit: limit item_iterator result counts, usage: DataListConverter.convert(:item_data, :table_data, item_data, item_iterator: {filter: {limit: {size: 2}}})

item_iterator count: count item_iterator items, usage: DataListConverter.convert(:xls_file, :item_data, {filename: 'result.xls'}, item_iterator: {filter: {count: {size: 10}}}), it will print current item counts every size.

Extend

You can add your data types and filters, example:

DataListConverter.register_converter(
  :records, :item_iterator, lambda { |records, options|
    columns = options[:columns]
    lambda { |&block|
      records.find_each do |record|
        item = columns.map do |column|
          [column.first.to_sym, record.send(column[1])]
        end.to_h
        block.call(item)
      end
    }
  })

DataListConverter.register_filter(
  :item_iterator, :limit, lambda { |proc, options|
    limit_size = options[:size] || 10
    lambda { |&block|
      limit = 0
      proc.call do |item|
        block.call(item)
        limit += 1
        break if limit >= limit_size
      end
    }
  })