paperclip upload from url

有时候我们的程序中需要远程获取并保存图片， 根据url去保存也很简单：

has_attached_file :asset , :styles => { :thumb => "100x100>" }
def asset_from_url(url)
  extname = File .extname(url)
  basename = File .basename(url, extname)
  file = Tempfile. new ([basename, extname])
  file.binmode
  open( URI .parse(url)) do |data|
    file.write data.read
  end
  file.rewind
  self .asset = file
end

使用：

image = Image.new
image.asset_from_url(url)
image.save

其他详情 : http://trevorturk.wordpress.com/2008/12/11/easy-upload-via-url-with-paperclip/