From: Pit Capitain <pit@...>
Date: 2007-01-27T22:45:37+09:00
Subject: Re: Howto write SAX2Parser stream in to a file

Luca g. Soave schrieb:
> I'm new to Ruby and trying to write a stream in to a file,
> but I can just get an empty one. I tryed in different way
> found heare on the forum ( IO lib, Rio lib,
> out_file << "#{doc.parse}" and so on ).
> 
> Here I show you the simplest :
> 
> -----------------------------------------
> require 'rexml/parsers/sax2parser'
> 
> file = File.new "lapatyXML.xml"
> doc = REXML::Parsers::SAX2Parser.new file
> 
> doc.listen(:characters, ["title"]) do |title|
>   print "\"#{title}\" : "
> end
> doc.listen(:characters, ["link"]) do |link|
>   print "#{link} : "
> end
> doc.listen(:characters, ["dc:date"]) do |date|
>   print "#{date} : "
> end
> doc.listen(:characters, ["dc:subject"]) do |subject|
>   puts "#{subject}"
> end
> 
> File.open("outfile.xls","w") do |out_file|
>   out_file.write "#{doc.parse}"
> end
> ------------------------------------------
> 
> Nothing seems to work, I just get an empty file "outfile.xls" .

Luca, welcome to Ruby! I've never used REXML before, so all this might 
be completely wrong, but with the line

   out_file.write "#{doc.parse}"

you are writing the result of the #parse method to the output file, 
which might be just an empty string if the result is nil. I think all 
the calls of print and puts in your listeners just write to the console 
where you run your script. To get what you want I would try to change 
your program to:

   require 'rexml/parsers/sax2parser'

   file = File.new "lapatyXML.xml"
   doc = REXML::Parsers::SAX2Parser.new file

   File.open("outfile.xls","w") do |out_file|

     doc.listen(:characters, ["title"]) do |title|
       out_file.print "\"#{title}\" : "
     end
     doc.listen(:characters, ["link"]) do |link|
       out_file.print "#{link} : "
     end
     doc.listen(:characters, ["dc:date"]) do |date|
       out_file.print "#{date} : "
     end
     doc.listen(:characters, ["dc:subject"]) do |subject|
       out_file.puts "#{subject}"
     end

     doc.parse

   end

Regards,
Pit