From: Alex Gutteridge <alexg@...>
Date: 2007-06-25T16:55:30+09:00
Subject: Re: Newbie needs help! Strange error in code

On 25 Jun 2007, at 16:31, Tom Savage wrote:

> Hi, I am very new to Ruby and yesterday I managed to get a simple  
> server
> operating which told me the time. I tried to extend this by adding  
> in a
> simple myvar = gets.chomp! and a print myvar in place of the date
> output. This is the whole code:
>
> test = gets.chomp!
> puts test
> require 'socket'
> port = (ARGV[0] || 80).to_i
> server = TCPServer.new('localhost', port)
> while (session = server.accept)
>   puts "Request: #{session.gets}"
>   session.print "HTTP/1.1 200/OK\r\nContent-type: text/html\r\n\r\n"
>   session.print "<html><body><h1>#{test}</h1></body></html>\r\n"
>   session.close
> end
>
> The problem is that I get and error when I run it which says  
> "`gets': No
> such file or directory - 1400 (Errno::ENOENT)"
>
> I run the program with "ruby x.rb 1400" 1400 is the port number
>
> If anyone can help me, I will be eternally thankfully.
>
> -- 
> Posted via http://www.ruby-forum.com/.
>

'gets' isn't doing what you think it is:

------------------------------------------------------------ Kernel#gets
      gets(separator=$/)    => string or nil
------------------------------------------------------------------------
      Returns (and assigns to +$_+) the next line from the list of files
      in +ARGV+ (or +$*+), or from standard input if no files are  
present
      on the command line. Returns +nil+ at end of file. The optional
      argument specifies the record separator. The separator is included
      with the contents of each record. A separator of +nil+ reads the
      entire contents, and a zero-length separator reads the input one
      paragraph at a time, where paragraphs are divided by two
      consecutive newlines. If multiple filenames are present in +ARGV+,
      +gets(nil)+ will read the contents one file at a time.

         ARGV << "testfile"
         print while gets

      _produces:_

         This is line one
         This is line two
         This is line three
         And so on...

By calling your script as 'ruby x.rb 1400' gets attempts to read the  
first line of a file called '1400', which doesn't exist. If you run  
the program as 'ruby x.rb' and then type 1400 when it pauses you will  
get the behavior (I think) you expect. Alternatively replace  
gets.chomp! with ARGV[0].chomp.

Alex Gutteridge

Bioinformatics Center
Kyoto University