Class: ZipTricks::OutputEnumerator

Inherits:
Object
  • Object
show all
Defined in:
lib/zip_tricks/output_enumerator.rb

Overview

Can be used as a Rack response body directly. Will yield a Streamer for adding entries to the archive and writing zip entry bodies.

Direct Known Subclasses

RackBody

Instance Method Summary collapse

Constructor Details

#initialize(**streamer_options, &blk) ⇒ OutputEnumerator

Prepares a new Rack response body with a Zip output stream. The block given to the constructor will be called when the response body will be read by the webserver, and will receive a Streamer as it's block argument. You can then add entries to the Streamer as usual. The archive will be automatically closed at the end of the block.

# Precompute the Content-Length ahead of time
content_length = ZipTricks::SizeEstimator.estimate do | estimator |
  estimator.add_stored_entry(filename: 'large.tif', size: 1289894)
end

# Prepare the response body.
# The block will only be called when the
# response starts to be written.
body = ZipTricks::OutputEnumerator.new do | streamer |
  streamer.add_stored_entry(filename: 'large.tif', size: 1289894, crc32: 198210)
  streamer << large_file.read(1024*1024) until large_file.eof?
  ...
end

return [200, {'Content-Type' => 'binary/octet-stream',
'Content-Length' => content_length.to_s}, body]



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# File 'lib/zip_tricks/output_enumerator.rb', line 29

def initialize(**streamer_options, &blk)
  @streamer_options = streamer_options.to_h
  @archiving_block = blk
end

Instance Method Details

#each ⇒ Object

Executes the block given to the constructor with a Streamer and passes each written chunk to the block given to the method. This allows one to "take" output of the ZIP piecewise.



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# File 'lib/zip_tricks/output_enumerator.rb', line 37

def each
  if block_given?
    block_write = ZipTricks::BlockWrite.new { |chunk| yield(chunk) }
    ZipTricks::Streamer.open(block_write, **@streamer_options, &@archiving_block)
  else
    enum_for(:each)
  end
end