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| | # -*- encoding: binary -*-
# frozen_string_literal: true
require 'tempfile'
require 'rack/utils'
module Rack
# 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.
#
# rack.input is required to be rewindable, so if your input stream IO is non-rewindable
# by nature (e.g. a pipe or a socket) then you can wrap it in an object of this class
# to easily make it 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.
class RewindableInput
def initialize(io)
@io = io
@rewindable_io = nil
@unlinked = false
end
def gets
make_rewindable unless @rewindable_io
@rewindable_io.gets
end
def read(*args)
make_rewindable unless @rewindable_io
@rewindable_io.read(*args)
end
def each(&block)
make_rewindable unless @rewindable_io
@rewindable_io.each(&block)
end
def rewind
make_rewindable unless @rewindable_io
@rewindable_io.rewind
end
# Closes this RewindableInput object without closing the originally
# wrapped IO oject. Cleans up any temporary resources that this RewindableInput
# has created.
#
# This method may be called multiple times. It does nothing on subsequent calls.
def close
if @rewindable_io
if @unlinked
@rewindable_io.close
else
@rewindable_io.close!
end
@rewindable_io = nil
end
end
private
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) if @rewindable_io.respond_to?(:set_encoding)
@rewindable_io.binmode
if filesystem_has_posix_semantics?
raise 'Unlink failed. IO closed.' if @rewindable_io.closed?
@unlinked = true
end
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
def filesystem_has_posix_semantics?
RUBY_PLATFORM !~ /(mswin|mingw|cygwin|java)/
end
end
end
|