CSV导出-这是怎么回事？

Question

Using the following code to (try and) generate a CSV. I'm not sure what's happening, when I run this I get a prompt to download & open the CSV in Excel (which is what I want) but it has nothing in it....I also noticed a file is saved in the project root (named 'schedule_23Feb12' for example) and this does have the expected content!?! Subsequent re-runs cause the download to be duplicated but the root file to be overwritten.

Any ideas?

def schedulecsv
@products = Product.where('release_date > ?', Date.today)
filename ="schedule_#{Date.today.strftime('%d%b%y')}"
   csv_data = CSV.generate filename do |csv|
    csv << ["cat_no","version"]
      @products.each do |p|
        csv << [p.cat_no,p.version]
      end
  end
  send_data csv_data,
  :type => 'text/csv; charset=iso-8859-1; header=present',
  :disposition => "attachment; filename=#{filename}.csv"
end   

Answer 1

Sounds like a bug i've run into before with Internet Explorer. What you're seeing could be either a cached version of the document or worse no document at all because it expired from IE's cache as soon as it downloaded (happens if Cache-control: max-age=0 ).

Try setting an explicit Cache-control: max-age=5 as one of your headers so you get fresh copies of the document.