From: fedzor <fedzor@...>
Date: 2008-02-23T07:06:14+09:00
Subject: Re: Efficient file downloading


On Feb 21, 2008, at 8:54 PM, Kyle Hunter wrote:

> Hello,
>
> I'm using open-uri to download files using a buffer. It seems very
> inefficient in terms of resource usage (CPU is ~10-20% in usage).
>
> If possible, I'd like some suggestions for downloading a file which
> names the outputted file the same as the URL, and does not actually
> write if the file comes out to a 404 (or some other exception hits).
>
> Current code:
> BUFFER_SIZE=4096
> def download(url)
>   from = open(url)
>   if (buffer = from.read(BUFFER_SIZE))
>     puts "Downloading #{url}"
>     File.open(url.split('/').last, 'wb') do |file|
>     begin
>       file.write(buffer)
>     end while (buffer = from.read(BUFFER_SIZE))
>     end
>   end
> end

$ sudo gem install snoopy
$ snoopy http://en.wikipedia.org/wiki/Main_Page
	=> file Main_Page

Ta dah! there's a lot of magic behind it right now, and torrentz  
don't work (fixed on my machine, need to release it). It does  
segmented downloading, ideal for large files. For smaller ones, it  
still works fine.

The problem with open-uri is this: it downloads the whole thing to  
your tmp directory first, so using the BUFFER_SIZE thing won't  
actually help.

snoopy won't not write the file if there's an error.

-------------------------------------------------------|
~ Ari
Some people want love
Others want money
Me... Well...
I just want this code to compile