Make path method working for StringIO in test memory storage

[dmitry]

It is not possible to pass the path to the send_file method when using the memory storage. Currently, I have the following code:

send_file(
  resume.file.to_io.path
)

I want to use the x-accel-redirect header feature in Nginx to pass the io.path location to Nginx and let it stream the data, rather than streaming the data directly from the Rails application.

In all environments except for test, the file system is used. The test environment uses the memory storage, which returns a StringIO object, which does not have a file associated with it and therefore does not have a path. What is the best solution to make this work? Is using is_a?(StringIO) condition the only option, or is there something better?

[janko]

Yeah, the memory storage cannot retrieve the path, because the uploaded file doesn't exist on the filesystem. You'll need to create a conditional for memory storage, something like:

class ApplicationController < ActionController::Base
  private

  def send_upload(uploaded_file, ...)
    if uploaded_file.storage.is_a?(Shrine::Storage::Memory)
      send_file uploaded_file.download.path, ...
    else
      send_file uploaded_file.to_io.path, ...
    end
  end
end

# in your controller:
send_upload(resume.file)

You could also use send_data uploaded_file.read, ... for the memory storage path.

[dmitry]

@janko thank you for the quick response, seems like that's the only way to do it.

That's what I did:

    send_upload(
      file,
      type: inline ? 'application/pdf' : 'application/force-download',
      disposition: inline ? :inline : :attachment,
      filename: "#{sanitize_filename(filename)}.pdf"
    )
  end

  private

  def send_upload(uploaded_file, **options)
    if uploaded_file.storage.is_a?(Shrine::Storage::Memory)
      send_file uploaded_file.download.path, **options
    else
      send_file uploaded_file.to_io.path, **options
    end
  end