class Rack::RewindableInput

Class which can make any IO object rewindable, including non-rewindable ones. It does this by buffering the data into a tempfile, which is rewindable.

Don’t forget to call close when you’re done. This frees up temporary resources that RewindableInput uses, though it does not close the original IO object.

Public Class Methods

new (io)

Source

# File lib/rack/rewindable_input.rb, line 31
def initialize(io)
  @io = io
  @rewindable_io = nil
  @unlinked = false
end

Public Instance Methods

close ()

Source

# File lib/rack/rewindable_input.rb, line 67
def close
  if @rewindable_io
    if @unlinked
      @rewindable_io.close
    else
      @rewindable_io.close!
    end
    @rewindable_io = nil
  end
end

Closes this RewindableInput object without closing the originally wrapped IO object. Cleans up any temporary resources that this RewindableInput has created.

This method may be called multiple times. It does nothing on subsequent calls.

each (&block)

Source

# File lib/rack/rewindable_input.rb, line 47
def each(&block)
  make_rewindable unless @rewindable_io
  @rewindable_io.each(&block)
end

gets ()

Source

# File lib/rack/rewindable_input.rb, line 37
def gets
  make_rewindable unless @rewindable_io
  @rewindable_io.gets
end

read (*args)

Source

# File lib/rack/rewindable_input.rb, line 42
def read(*args)
  make_rewindable unless @rewindable_io
  @rewindable_io.read(*args)
end

rewind ()

Source

# File lib/rack/rewindable_input.rb, line 52
def rewind
  make_rewindable unless @rewindable_io
  @rewindable_io.rewind
end

size ()

Source

# File lib/rack/rewindable_input.rb, line 57
def size
  make_rewindable unless @rewindable_io
  @rewindable_io.size
end

Private Instance Methods

filesystem_has_posix_semantics? ()

Source

# File lib/rack/rewindable_input.rb, line 111
def filesystem_has_posix_semantics?
  RUBY_PLATFORM !~ /(mswin|mingw|cygwin|java)/
end

make_rewindable ()

Source

# File lib/rack/rewindable_input.rb, line 80
def make_rewindable
  # Buffer all data into a tempfile. Since this tempfile is private to this
  # RewindableInput object, we chmod it so that nobody else can read or write
  # it. On POSIX filesystems we also unlink the file so that it doesn't
  # even have a file entry on the filesystem anymore, though we can still
  # access it because we have the file handle open.
  @rewindable_io = Tempfile.new('RackRewindableInput')
  @rewindable_io.chmod(0000)
  @rewindable_io.set_encoding(Encoding::BINARY)
  @rewindable_io.binmode
  # :nocov:
  if filesystem_has_posix_semantics?
    raise 'Unlink failed. IO closed.' if @rewindable_io.closed?
    @unlinked = true
  end
  # :nocov:

  buffer = "".dup
  while @io.read(1024 * 4, buffer)
    entire_buffer_written_out = false
    while !entire_buffer_written_out
      written = @rewindable_io.write(buffer)
      entire_buffer_written_out = written == buffer.bytesize
      if !entire_buffer_written_out
        buffer.slice!(0 .. written - 1)
      end
    end
  end
  @rewindable_io.rewind
end