Rails 3: Sending tempfiles for download
When you create a temporary file (e.g. to store a generated Excel sheet) and try to send it to the browser from a controller, it won't work by default. Take this controller action:
Copyclass FoosController < ApplicationController def download file = Tempfile.new('foo') file.puts 'foo' file.close send_file file.path end end
Accessing this controller action will usually raise a 404 not found in the browser and the Apache log will say:
CopyThe given path was above the root path: xsendfile: unable to find file: /tmp/foo20110721-28050-1h104da-0
The reason for this is that Rails 3 uses X-Sendfile for file downloads and Apache is only allowed to transfer files from a whitelist of paths that should not include /tmp.
One solution for this is to save the tempfile in your project directory's tmp instead:
Copyfile = Tempfile.new('foo', 'tmp')
Note that depending on your setup, you might need to change that file's permissions so Apache can read it.
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