module ActiveStorage::Downloading

def download_blob_to(file) #:doc:

:doc:
Efficiently downloads blob data into the given file. 
def download_blob_to(file) #:doc:
  file.binmode
  blob.download { |chunk| file.write(chunk) }
  file.flush
  file.rewind
end

def download_blob_to_tempfile #:doc:

:doc:
Opens a new tempfile in #tempdir and copies blob data into it. Yields the tempfile. 
def download_blob_to_tempfile #:doc:
  open_tempfile_for_blob do |file|
    download_blob_to file
    yield file
  end
end

def open_tempfile_for_blob 

def open_tempfile_for_blob
  tempfile = Tempfile.open([ "ActiveStorage", blob.filename.extension_with_delimiter ], tempdir)
  begin
    yield tempfile
  ensure
    tempfile.close!
  end
end

def tempdir #:doc:

:doc:
Returns the directory in which tempfiles should be opened. Defaults to +Dir.tmpdir+. 
def tempdir #:doc:
  Dir.tmpdir
end