How can I download multiple .xlsx files using axlsx gem? - download

Question

Hi I'm having trouble downloading multiple files with axlsx. The problem is I'm sending an array of Id's to the controller and asking it to download the report using the render command. It raises an AbstractController::DoubleRenderError. I was thinking of overriding the error but realized it's a bad idea, I don't know what else to do... Any suggestions? Thanks.
My controller code looks like this:
def download_report
params[:user_id].each do |user_id|
#report = Report.find_by(:user_id => user_id)
render :xlsx => "download_report", :filename => "#{#report.user.last_name}.xlsx"
end
end
My axlsx template:
wb = xlsx_package.workbook
wb.add_worksheet(name: "Reports") do |sheet|
wb.styles do |s|
# template code
end
end

Answer 1

It is the built in expectation of Rails that you would call render once per request. And, the browser is going to expect one response per request. So, you are going to have to do something else!
You can use render_to_string, and combine the results into a zip file, serving that. See the bottom of this response.
Or, you could create a single spreadsheet and have each user's report show up on their own worksheet.
Or, on the client side, you could use javascript to request each spreadsheet and download each one separately.
The zip one would be something like this code, which uses render_to_string, rubyzip, and send_data:
def download_report
compressed_filestream = Zip::ZipOutputStream.write_buffer do |zos|
params[:user_id].each do |user_id|
#report = Report.find_by(:user_id => user_id)
content = render_to_string :xlsx => "download_report", :filename => "#{#report.user.last_name}.xlsx"
zos.put_next_entry("user_#{user_id}.xlsx")
zos.print content
end
end
compressed_filestream.rewind
send_data compressed_filestream.read, :filename => 'download_report.zip', :type => "application/zip"
end
Axlsx requires rubyzip, so you should have it already. And you probably want to lookup each user and use their name for the spreadsheet, unless you have it otherwise.