class SeedFu::Writer
{Writer} is used to programmatically generated seed files. For example, you might want to write a script which converts data in a CSV file to a valid Seed Fu seed file, which can then be imported.
@example Basic usage
SeedFu::Writer.write('path/to/file.rb', :class_name => 'Person', :constraints => [:first_name, :last_name]) do |writer| writer.add(:first_name => 'Jon', :last_name => 'Smith', :age => 21) writer.add(:first_name => 'Emily', :last_name => 'McDonald', :age => 24) end # Writes the following to the file: # # Person.seed(:first_name, :last_name, # {:first_name=>"Jon", :last_name=>"Smith", :age=>21}, # {:first_name=>"Emily", :last_name=>"McDonald", :age=>24} # )
Public Class Methods
@param [Hash] options @option options [String] :class_name Required The name of the Active Record model to
generate seeds for
@option options [Fixnum] :chunk_size (100) The number of seeds to write before generating a
`# BREAK EVAL` line. (Chunking reduces memory usage when loading seeds.)
@option options [:seed, :seed_once] :seed_type (:seed) The method to use when generating
seeds. See {ActiveRecordExtension} for details.
@option options [Array<Symbol>] :constraints ([:id]) The constraining attributes for the seeds
# File lib/seed-fu/writer.rb, line 34 def initialize(options = {}) @options = self.class.default_options.merge(options) raise ArgumentError, "missing option :class_name" unless @options[:class_name] end
Creates a new instance of {Writer} with the `options`, and then calls {#write} with the `io_or_filename` and `block`
# File lib/seed-fu/writer.rb, line 41 def self.write(io_or_filename, options = {}, &block) new(options).write(io_or_filename, &block) end
Public Instance Methods
Add a seed. Must be called within a block passed to {#write}. @param [Hash] seed The attributes for the seed
# File lib/seed-fu/writer.rb, line 67 def <<(seed) raise "You must add seeds inside a SeedFu::Writer#write block" unless @io buffer = '' if chunk_this_seed? buffer << seed_footer buffer << "# BREAK EVAL\n" buffer << seed_header end buffer << ",\n" buffer << ' ' + seed.inspect @io.write(buffer) @count += 1 end
Writes the necessary headers and footers, and yields to a block within which the actual seed data should be writting using the `#<<` method.
@param [IO] io_or_filename The IO to which writes will be made. (If an `IO` is given, it is
your responsibility to close it after writing.)
@param [String] io_or_filename The filename of a file to make writes to. (Will be opened and
closed automatically.)
@yield [self] make calls to `#<<` within the block
# File lib/seed-fu/writer.rb, line 53 def write(io_or_filename, &block) raise ArgumentError, "missing block" unless block_given? if io_or_filename.respond_to?(:write) write_to_io(io_or_filename, &block) else File.open(io_or_filename, 'w') do |file| write_to_io(file, &block) end end end
Private Instance Methods
# File lib/seed-fu/writer.rb, line 128 def chunk_this_seed? @count != 0 && (@count % @options[:chunk_size]) == 0 end
# File lib/seed-fu/writer.rb, line 100 def file_header <<-END # DO NOT MODIFY THIS FILE, it was auto-generated. # # Date: #{Time.now} # Seeding #{@options[:class_name]} # Written with the command: # # #{$0} #{$*.join} # END end
# File lib/seed-fu/writer.rb, line 119 def seed_header constraints = @options[:constraints] && @options[:constraints].map(&:inspect).join(', ') "#{@options[:class_name]}.#{@options[:seed_type]}(#{constraints}" end
# File lib/seed-fu/writer.rb, line 89 def write_to_io(io) @io, @count = io, 0 @io.write(file_header) @io.write(seed_header) yield(self) @io.write(seed_footer) @io.write(file_footer) ensure @io, @count = nil, nil end