[chef] resource for copy local file?

[< >]

I got another problem regarding resource for copy local file. 
eg. Download one file from http server, then backup the file:

remote_file "/httpfile" do
        source "http://wiki.opscode.com/display/chef/Home";
        mode "0666"
end
file "/httpfile.bak" do
        content IO.read("/httpfile")
end

I got error: FATAL: Errno::ENOENT: No such file or directory - /httpfile

This is because /httpfile is non-exist when I start chef-client. How can I 
copy
such kind of file?