Rails: Permission denied for File.delete - ruby-on-rails

Question

I am creating a very simple web app that allows the user to upload a .zip file that I temporarily save in the tmp folder inside my application, parse the contents using zipfile and then delete the file after I'm done.
I managed to upload the file and copy it to the tmp folder, I can successfully parse it and get the results I want, but when I try to delete the file I get a permission denied error.
here's my view:
<%= form_tag({action: :upload}, multipart: true) do %>
<%= file_field_tag :software %>
<br/><br/>
<%= submit_tag("UPLOAD") %>
<% end %>
And here's my controller:
def upload
#file = params[:software]
#name = #file.original_filename
File.open(Rails.root.join('tmp', #name), 'wb') do |file|
file.write(#file.read)
end
parse
File.delete("tmp/#{#name}")
render action: "show"
end
I have tried using FileUtils.rm ("tmp/#{#name}") as well, and I also tried setting File.chmod(0777, "tmp/#{#name}") before deletion but to no avail. Changing the deletion path to Rails.root.join('tmp', #name) like the File.open block also doesn't fix it. I can totally delete the file via console so I don't know what can be the matter.
EDIT: The parse method:
def parse
require 'zip'
Zip::File.open("tmp/#{#nome}") do |zip_file|
srcmbffiles = File.join("**", "src", "**", "*.mbf")
entry = zip_file.glob(srcmbffiles).first
#stream = entry.get_input_stream.read
puts #stream
end
end

Answer 1

The issue was that for some reason my file was not being closed for deletion in either the File.open block or the Zip::File.open block. My solution was to close it manually and avoid using open blocks, changing this snippet:
File.open(Rails.root.join('tmp', #name), 'wb') do |file|
file.write(#file.read)
end
into this:
f = File.open(Rails.root.join('tmp', #nome), 'wb+')
f.write(#file.read)
f.close
and changing my parse method from this:
def parse
require 'zip'
Zip::File.open("tmp/#{#nome}") do |zip_file|
srcmbffiles = File.join("**", "src", "**", "*.mbf")
entry = zip_file.glob(srcmbffiles).first
#stream = entry.get_input_stream.read
puts #stream
end
end
to this:
def parse
require 'zip'
zf = Zip::File.open("tmp/#{#nome}")
srcmbffiles = File.join("**", "src", "**", "*.mbf")
entry = zf.glob(srcmbffiles).first
#stream = zf.read(entry)
puts #stream
zf.close()
end
Notice that I changed the way I populate #stream because apparently entry.get_input_stream also locks the file you're accessing.

Answer 2

The writing process may be still locking the file. You may have to wait until that process is complete.

Answer 3

'"tmp/#{#name}"' is not right path. Just use 'Rails.root.join('tmp', #name)'