110 lines
3.6 KiB
Ruby
110 lines
3.6 KiB
Ruby
require 'tempfile'
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module Rack
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# Class which can make any IO object rewindable, including non-rewindable ones. It does
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# this by buffering the data into a tempfile, which is rewindable.
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#
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# rack.input is required to be rewindable, so if your input stream IO is non-rewindable
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# by nature (e.g. a pipe or a socket) then you can wrap it in an object of this class
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# to easily make it rewindable.
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#
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# Don't forget to call #close when you're done. This frees up temporary resources that
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# RewindableInput uses, though it does *not* close the original IO object.
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class RewindableInput
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def initialize(io)
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@io = io
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@rewindable_io = nil
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@unlinked = false
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end
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def gets
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make_rewindable unless @rewindable_io
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@rewindable_io.gets
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end
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def read(*args)
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make_rewindable unless @rewindable_io
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@rewindable_io.read(*args)
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end
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def each(&block)
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make_rewindable unless @rewindable_io
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@rewindable_io.each(&block)
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end
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def rewind
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make_rewindable unless @rewindable_io
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@rewindable_io.rewind
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end
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# Closes this RewindableInput object without closing the originally
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# wrapped IO oject. Cleans up any temporary resources that this RewindableInput
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# has created.
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#
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# This method may be called multiple times. It does nothing on subsequent calls.
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def close
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if @rewindable_io
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if @unlinked
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@rewindable_io.close
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else
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@rewindable_io.close!
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end
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@rewindable_io = nil
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end
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end
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private
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# Ruby's Tempfile class has a bug. Subclass it and fix it.
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class Tempfile < ::Tempfile
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def _close
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@tmpfile.close if @tmpfile
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@data[1] = nil if @data
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@tmpfile = nil
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end
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end
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def make_rewindable
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# Buffer all data into a tempfile. Since this tempfile is private to this
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# RewindableInput object, we chmod it so that nobody else can read or write
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# it. On POSIX filesystems we also unlink the file so that it doesn't
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# even have a file entry on the filesystem anymore, though we can still
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# access it because we have the file handle open.
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@rewindable_io = Tempfile.new('RackRewindableInput')
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@rewindable_io.chmod(0000)
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@rewindable_io.set_encoding(Encoding::BINARY) if @rewindable_io.respond_to?(:set_encoding)
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@rewindable_io.binmode
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if filesystem_has_posix_semantics? && !tempfile_unlink_contains_bug?
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@rewindable_io.unlink
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@unlinked = true
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end
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buffer = ""
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while @io.read(1024 * 4, buffer)
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entire_buffer_written_out = false
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while !entire_buffer_written_out
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written = @rewindable_io.write(buffer)
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entire_buffer_written_out = written == buffer.size
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if !entire_buffer_written_out
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buffer.slice!(0 .. written - 1)
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end
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end
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end
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@rewindable_io.rewind
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end
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def filesystem_has_posix_semantics?
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RUBY_PLATFORM !~ /(mswin|mingw|cygwin|java)/
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end
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def tempfile_unlink_contains_bug?
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# The tempfile library as included in Ruby 1.9.1-p152 and later
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# contains a bug: unlinking an open Tempfile object also closes
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# it, which breaks our expected POSIX semantics. This problem
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# has been fixed in Ruby 1.9.2, but the Ruby team chose not to
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# include the bug fix in later versions of the 1.9.1 series.
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ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : "ruby"
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ruby_engine == "ruby" && RUBY_VERSION == "1.9.1" && RUBY_PATCHLEVEL >= 152
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end
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end
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end
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