From: "Eric I." <rubytraining@...>
Date: 2008-06-10T08:00:00+09:00
Subject: Re: Trying to add threading to parse a .txt file.

On Jun 9, 2:29 pm, jdevit...@gmail.com wrote:
> Hi All,
>
> I have code that will parse a text file line by line and then send the
> variable I want to a sub routine to send pages to people. My question
> is can I use threads to parse that text file with out duplicating the
> output. Below is the code it may make more sense to look at it.
>
> #!/usr/bin/ruby
>
> trap('SIGHUP','IGNORE')
>
> i = 0
>
> def autopage(pagenum,count)
>
>  begin
>
>   `snpp -s SERVER ADDRESS -f 'EOC Notify' -m 'test' #{pagenum}`
>   rescue
>     puts "#{pagenum} has NOT been paged."
>   else
>     puts "#{pagenum} has been paged. #{count} "
>   end
> end
>
> File.open('//var//lib//asterisk//agi-bin//pager_list.txt', 'r') do |
> f1|
>    while line = f1.gets
>       result = {}
>       pagenum,fname,lname=line.split(" ")
>       if line.split.empty?
>       else
>         if pagenum == "####"
>         else
>            count = (i += 1)
>            autopage(pagenum,count)
>            end
>          end
>        end
>      end
>
> Thanks!!


The parsing of the file itself, should not be threaded.  What you
should do is every time you read a line and determine that you need to
send a page, put the paging information into a Queue.

Then you can creat four, ten, or some other number of threads to
consume the paging information from the queue.  After pulling
something from the queue, they'll use the information to call your
autopage method.

For a good example, see the the short producer/consumer program
created by Robert Kellner that appears in the 'thread' library section
of the Pick Axe book (2nd ed).  In my version of the book it's on page
722, but page numbers seem to vary b/w printings and format.

If you don't mind my offering some additional unsolicited notes on
your code:

You have a few "if"s with empty "then"s.  Ruby has an "unless" which
is essentially the opposite of "if" that would make this code cleaner
(IMHO).

You can put a "rescue" at the top level inside a method without having
a begin/end block.  But you're right in that in other cases you do
need the begin/end block.

Hope that's helpful,

Eric

====

LearnRuby.com offers Rails & Ruby HANDS-ON public & ON-SITE
workshops.
   Ruby Fundamentals Wkshp          June 16-18     Ann Arbor, Mich.
   Ready for Rails Ruby Wkshp       June 23-24     Ann Arbor, Mich.
   Ruby on Rails Wkshp              June 25-27     Ann Arbor, Mich.
   Ruby Plus Rails Combo Wkshp      June 23-27     Ann Arbor, Mich
Please visit http://LearnRuby.com for all the details.