From: Jan Svitok <jan.svitok@...>
Date: 2006-11-03T23:52:20+09:00
Subject: Re: Using another program (Lynx) from within Ruby

On 11/3/06, z <news01.web@mailnull.com> wrote:
> I'm trying to write a script to read a list of URLS, get the HTTP response
> headers and <title> (if there is a page there) from each URL, and output to
> a CSV file in this format:
> URL, header, <title>
>
> I've started with something like this, using Lynx to get the headers.  The
> part that doesn't seem to work is this:
> `lynx -dump -head "#{line}"`  -- it doesn't want to put the url into the
> #{line} within the backticks.
>
> How do you insert a variable from Ruby into the shell command?  I'm ordering
> 4 Ruby books by mail today... I haven't seen anything like this in the ones
> that I've browsed though.
>
>
> Here is a larger section of the script:
>
> print "Enter the location of the input file: "
>     infile = gets.chomp
>
>     # open file
>     File.open(infile, "r") do |f|
>       # get HTTP headers with Lynx
>       output = f.each_line { |line| `lynx -dump -head "#{line}" | grep "HTTP"` }
> #      puts output to CVS file
> # TODO

Hi,

the #{} should work. Try replacing the command with echo to see to
what exactly it is expanded.

On a side note, you can use Net::HTTP for this task without calling
external program:
(from rdoc):

    response = nil
    Net::HTTP.start('some.www.server', 80) {|http|
      response = http.get('/index.html')
    }
    p response['content-type']
    p response.body