From: Michael Buffington <michael.buffington@...>
Date: 2005-04-21T08:49:46+09:00
Subject: Re: Newb CGI Question

Looks I've figure most of it. This sort of works:

#! /usr/bin/ruby

require 'cgicroak'

CGI.croak('html4') do |cgi|
	print(cgi.header("type" => "image/gif", "length" =>
File.size("image.gif"), "status" => "304"))
	File.read("agent.gif")
end

Problem is, the server reports that it can't display the image due to
errors. Any ideas what I'm doing wrong when I actually read the image
file in?


On 4/20/05, Michael Buffington <michael.buffington@gmail.com> wrote:
> This is really great - seeing Ruby errors definitely makes things more clear.
> 
> So, to test this all out, here's what my "index.cgi" looks like:
> #! /usr/bin/ruby
> require 'cgicroak'
> 
> CGI.croak('html4') do |cgi|
>         cgi.out("type" => "text/html") {"shizzle"}
> end
> 
> This works as expected. The word shizzle makes it to the browser.
> 
> However, when I execute this:
> #! /usr/bin/ruby
> require 'cgicroak'
> 
> CGI.croak('html4') do |cgi|
>         cgi.out("type" => "image/gif") {File.open("image.gif")}
> end
> 
> I get:
> Error NameError: undefined method `length'
> 
> I get the same thing with:
> #! /usr/bin/ruby
> require 'cgicroak'
> 
> CGI.croak('html4') do |cgi|
>         cgi.out("type" => "image/gif", "length" => File.size("image.gif"))
> {File.open("image.gif")}
> end
> 
> In either cases, if I use cgi.header instead of cgi.out, I get an error saying:
> "No header sent"
> 
> Any ideas about what's going on?
> 
> On 4/20/05, Paul Battley <pbattley@gmail.com> wrote:
> > I have found that you need to write the header manually, despite what
> > the docs say.
> >
> > This snippet will save you a lot of hassle whilst developing under
> > CGI.  It should trap errors and give a backtrace in the browser, as
> > well as indicate if you didn't send the header properly:
> >
> > ---- cgicroak.rb ----
> >
> > require 'cgi'
> >
> > class CGI
> >     def self.croak(*args)
> >         cgi = CGI.new(args)
> >         old_stdout = $stdout
> >         buffer = ''
> >         def buffer.write(s)
> >             self << s
> >         end
> >         $stdout = buffer
> >         begin
> >             yield(cgi)
> >             unless (buffer =~ /^Content-type:.*?\r?\n\r?\n/i)
> >                 raise RuntimeError, "No header sent"
> >             end
> >         rescue Exception => e
> >             buffer.replace('')
> >             print(cgi.header('type' => 'text/plain'))
> >             puts("Error\n\n")
> >             puts("#{e.class.to_s}: #{e.to_s}\n\n")
> >             puts(e.backtrace.join("\n"))
> >         end
> >         $stdout = old_stdout
> >         $stdout.write(buffer)
> >     end
> > end
> >
> > ---- index.cgi ----
> >
> > #!/path/to/your/ruby
> >
> > require 'croakcgi'
> >
> > CGI.croak('html4') do |cgi|
> >
> >     # Your requires go here
> >
> >     print(cgi.header)
> >
> >     # Your code
> >
> > end
> >
> > --- EOF ---
> >
> > Paul.
> >
> >
>