diff of Rack::Multipart::Parser for streaming uploads

streaming_rack_multipart_parser.diff

1c1
< require 'rack/utils'
---
> require 'streaming_upload'
3,4c3,18
< module Rack
<   module Multipart
---
> class StreamingMultipartRequest < ActionDispatch::Request
>   def parse_multipart(env)
>     Parser.new(env).parse
>   end
> 
>   # This code is mostly taken directly from Rack's Multipart::Parser class. It
>   # has been adapted to upload the file directly to S3 using a temporary
>   # filename, for later renaming, while we are reading off the socket. The file
>   # is also stored in a local tempfile as normal, since we need that for FFMPEG
>   # processing.
>   #
>   # I've copied the entire class rather than sub-classing because of the
>   # invasiveness of the change -- monkey patching in this functionality would
>   # be error prone as we update Rack versions.
>   #
>   # The diff from Rack::Multipart::Parser is available at https://gist.github.com/codekitchen/8290940
6c20,32
<       BUFSIZE = 16384
---
>     BUFSIZE = 65536
> 
>     EOL = "\r\n"
>     MULTIPART = %r|\Amultipart/.*boundary=\"?([^\";,]+)\"?|n
>     TOKEN = /[^\s()<>,;:\\"\/\[\]?=]+/
>     CONDISP = /Content-Disposition:\s*#{TOKEN}\s*/i
>     DISPPARM = /;\s*(#{TOKEN})=("(?:\\"|[^"])*"|#{TOKEN})/
>     RFC2183 = /^#{CONDISP}(#{DISPPARM})+$/i
>     BROKEN_QUOTED = /^#{CONDISP}.*;\sfilename="(.*?)"(?:\s*$|\s*;\s*#{TOKEN}=)/i
>     BROKEN_UNQUOTED = /^#{CONDISP}.*;\sfilename=(#{TOKEN})/i
>     MULTIPART_CONTENT_TYPE = /Content-Type: (.*)#{EOL}/ni
>     MULTIPART_CONTENT_DISPOSITION = /Content-Disposition:.*\s+name="?([^\";]*)"?/ni
>     MULTIPART_CONTENT_ID = /Content-ID:\s*([^#{EOL}]*)/ni
31c57
<           Utils.normalize_params(@params, name, data) unless data.nil?
---
>         ::Rack::Utils.normalize_params(@params, name, data) unless data.nil?
49c75
<         @params = Utils::KeySpaceConstrainedParams.new
---
>       @params = ::Rack::Utils::KeySpaceConstrainedParams.new
54c80
<         @boundary_size = Utils.bytesize(@boundary) + EOL.size
---
>       @boundary_size = ::Rack::Utils.bytesize(@boundary) + EOL.size
82c108
<           raise EOFError, "bad content body" if Utils.bytesize(@buf) >= BUFSIZE
---
>         raise EOFError, "bad content body" if ::Rack::Utils.bytesize(@buf) >= BUFSIZE
104c130
<               body = Tempfile.new("RackMultipart")
---
>             body = StreamingUpload.new("RackMultipart")
138c164
<           filename = Utils.unescape(filename)
---
>         filename = ::Rack::Utils.unescape(filename)
176d200
< end

wow my WIP diff was huge. In the end it came down to only one significant line changed? Crazy. Maybe Rack just needs DI for the Tempfile class.