From: ara.t.howard@...
Date: 2006-11-17T08:44:08+09:00
Subject: Re: Another IO.popen question ...

On Fri, 17 Nov 2006, Joel VanderWerf wrote:

> Adam Groves wrote:
>> Hi Joel,
>> 
>> thanks for the speedy reply! The problem is, I need to pass on a file 
>> object (which has been uploaded from a web page form) to 'convert' and not 
>> just a path. I should have made this clearer in my original post.
>> 
>> Any ideas?
>> 
>
> Untested, but maybe something like this?
>
> file = File.open("mypdf.pdf")
> IO.popen("convert -resize 700x700 pdf:-[0] png:-") do |f|
>  while (data=file.read(N))
>    f.write data
>  end
> end

careful, if you don't read the child will block when the pipe becomes full i
think.  you might need to add

   file = File.open("mypdf.pdf")

   png =
     IO.popen("convert -resize 700x700 pdf:-[0] png:-") do |f|
       while (data=file.read(N))
         f.write data
       end
       f.close_write
       f.read
     end

not sure if that was obvious or not...  sorry if it was.

-a
-- 
my religion is very simple.  my religion is kindness. -- the dalai lama