From: Tanaka Akira <akr@...17n.org>
Date: 2003-11-05T02:20:47+09:00
Subject: Re: CGI uses file size to distinguish between regular values and files

In article <1067952745.419615.23337.nullmailer@picachu.netlab.jp>,
  matz@ruby-lang.org (Yukihiro Matsumoto) writes:

> How about
>
>   require 'fileutils'
>   File.open(upload, 'w') {|f| FileUtils.copy_stream(file,f)}
>
> ?  It's bit longer, but works now without any modifies.

I see.  It is a solution but I found that I misunderstand the problem.

I thought that we cannot assume cgi['file'] has an actual file.  But
the assumption was correct in ruby-1.6 because always cgi.rb use
Tempfile since StringIO was not bundled.

It is documented in cgi.rb:

# === Get multipart form values
# 
#   require "cgi"
#   cgi = CGI.new
#   value = cgi['field_name']   # <== value string for 'field_name'
#   value.read                  # <== body of value
#   value.local_path            # <== path to local file of value
#   value.original_filename     # <== original filename of value
#   value.content_type          # <== content_type of value

The existence of the method `local_path' means that there is an actual
file in somewere.

But now local_path returns invalid pathname such as
"<StringIO:0x401fe6d8>" for smaller file.

So the problem is an incompatibility between ruby-1.6 and ruby-1.8.

It can be solved by:

* obsolete `local_path' and update documentation,
* don't use StringIO or
* switch StringIO to Tempfile when local_path is called.
-- 
Tanaka Akira