From: Paul Battley <pbattley@...>
Date: 2005-04-21T07:35:08+09:00
Subject: Re: Newb CGI Question

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.