Class: IOStreams::Record::Writer

Inherits:
Writer
  • Object
show all
Defined in:
lib/io_streams/record/writer.rb

Overview

Example, implied header from first record:

IOStreams.path('file.csv').writer(:hash) do |stream|
  stream << {name: 'Jack', address: 'Somewhere', zipcode: 12345}
  stream << {name: 'Joe', address: 'Lost', zipcode: 32443, age: 23}
end

Instance Attribute Summary

Attributes inherited from Writer

#output_stream

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Writer

open

Constructor Details

#initialize(line_writer, columns: nil, **args) ⇒ Writer

Create a Tabular writer that takes individual Parse a delimited data source.

Parameters

delimited: [#<<]
  Anything that accepts a line / record at a time when #<< is called on it.

format: [Symbol]
  :csv, :hash, :array, :json, :psv, :fixed

For all other parameters, see Tabular::Header.new



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# File 'lib/io_streams/record/writer.rb', line 37

def initialize(line_writer, columns: nil, **args)
  unless line_writer.respond_to?(:<<)
    raise(ArgumentError, 'Stream must be a IOStreams::Line::Writer or implement #<<')
  end

  @tabular     = IOStreams::Tabular.new(columns: columns, **args)
  @line_writer = line_writer

  # Render header line when `columns` is supplied.
  @line_writer << @tabular.render_header if columns && @tabular.requires_header?
end

Class Method Details

.file(file_name, original_file_name: file_name, delimiter: $/, **args, &block) ⇒ Object

When writing to a file also add the line writer stream



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# File 'lib/io_streams/record/writer.rb', line 20

def self.file(file_name, original_file_name: file_name, delimiter: $/, **args, &block)
  IOStreams::Line::Writer.file(file_name, original_file_name: original_file_name, delimiter: delimiter) do |io|
    yield new(io, **args, &block)
  end
end

.stream(line_writer, original_file_name: nil, **args) {|new(line_writer, **args)| ... } ⇒ Object

Write a record as a Hash at a time to a stream. Note:

  • The supplied stream must already be a line stream, or a stream that responds to :<<

Yields:

  • (new(line_writer, **args)) 


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# File 'lib/io_streams/record/writer.rb', line 12

def self.stream(line_writer, original_file_name: nil, **args)
  # Pass-through if already a record writer
  return yield(line_writer) if line_writer.is_a?(self.class)

  yield new(line_writer, **args)
end

Instance Method Details

#<<(hash) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/io_streams/record/writer.rb', line 49

def <<(hash)
  raise(ArgumentError, '#<< only accepts a Hash argument') unless hash.is_a?(Hash)

  if @tabular.header?
    # Extract header from the keys from the first row when not supplied above.
    @tabular.header.columns = hash.keys
    @line_writer << @tabular.render_header
  end
  @line_writer << @tabular.render(hash)
end