generate ZIP from generated PDFs with wicked_pdf - ruby-on-rails-3

Question

In my invoice system, I want a backup function to download all invoices at once in one zip file.
This system is running on heroku - so it's only possible to save the pdfs temporary.
I've the rubyzip and wicked_pdf gem installed.
My current code in the controller:
def zip_all_bills
#bill = Bill.all
if #bill.count > 0
t = Tempfile.new("bill_tmp_#{Time.now}")
Zip::ZipOutputStream.open(t.path) do |z|
#bill.each do |bill|
#bills = bill
#customer = #bills.customer
#customer_name = #customer.name_company_id
t = WickedPdf.new.pdf_from_string(
render :template => '/bills/printing.html.erb',
:disposition => "attachment",
:margin => { :bottom => 23 },
:footer => { :html => { :template => 'pdf/footer.pdf.erb' } }
)
z.puts("invoice_#{bill.id}")
z.print IO.read(t.path)
end
end
send_file t.path, :type => "application/zip",
:disposition => "attachment",
:filename => "bills_backup"
t.close
end
respond_to do |format|
format.html { redirect_to bills_url }
end
end
This ends with the message
IOError in BillsController#zip_all_bills closed stream

Answer 1

I think what is wrong in your code is that you have t for your zip but you also also use it for individual pdfs. So I think when you try to use the tempfile for a pdf it is a problem because you are already using it for the zip.
But I don't think you need to use tempfiles at all (and I never actually got a tempfile solution working on Heroku)
Here is a controller method that works for me--also using wickedpdf and rubyzip on heroku. Note that I'm not using a Tempfile instead I'm just doing everything with StringIO (at least I think that's the underlying tech).
def dec_zip
require 'zip'
#grab some test records
#coverages = Coverage.all.limit(10)
stringio = Zip::OutputStream.write_buffer do |zio|
#coverages.each do |coverage|
#create and add a text file for this record
zio.put_next_entry("#{coverage.id}_test.txt")
zio.write "Hello #{coverage.agency_name}!"
#create and add a pdf file for this record
dec_pdf = render_to_string :pdf => "#{coverage.id}_dec.pdf", :template => 'coverages/dec_page', :locals => {coverage: coverage}, :layout => 'print'
zio.put_next_entry("#{coverage.id}_dec.pdf")
zio << dec_pdf
end
end
# This is needed because we are at the end of the stream and
# will send zero bytes otherwise
stringio.rewind
#just using variable assignment for clarity here
binary_data = stringio.sysread
send_data(binary_data, :type => 'application/zip', :filename => "test_dec_page.zip")
end