# -*- encoding: binary -*-
# frozen_string_literal: true
require 'tempfile'
require_relative 'constants'
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.
#
# 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
# Makes rack.input rewindable, for compatibility with applications and middleware
# designed for earlier versions of Rack (where rack.input was required to be
# rewindable).
class Middleware
def initialize(app)
@app = app
end
def call(env)
env[RACK_INPUT] = RewindableInput.new(env[RACK_INPUT])
@app.call(env)
end
end
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
def size
make_rewindable unless @rewindable_io
@rewindable_io.size
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.
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)
@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
def filesystem_has_posix_semantics?
RUBY_PLATFORM !~ /(mswin|mingw|cygwin|java)/
end
end
end
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