`dispatch_request': no such request during Net::SFTP.upload

Question

I'm using Net::SFTP to upload a file to a server. Here is the code:

uri = URI.parse('sftp://host.org')
io = StringIO.new(csv_string)
timeout 120 do
  Net::SFTP.start(uri.host,ENV['SFTP_USER'],:password=>ENV['SFTP_PASS'],:port=>22)  do |sftp|
    sftp.upload(io, "/ftpguest/Medstro/" + file_name)
  end
end

When I run the code, it successfully connects to the host and uploads a zero-byte file with the correct filename. Then it throws this exception:

lib/ruby/gems/2.3.0/gems/net-sftp-2.1.2/lib/net/sftp/session.rb:947:in `dispatch_request': no such request `403046400' (Net::SFTP::Exception)

The file contents aren't uploaded, I just get a zero-byte file. I can't find anything on Google. Does anyone know how to troubleshoot this?

FYI, I can upload the file fine using WinSCP.

Answer 1

Updating the net-ssh gem to version 4.0.1 solved this problem.

Answer 2

Ran into this today. Make sure you specify the version of sftp that your server speaks. You can run version on your sftp server's shell to find out:

sftp> version
SFTP protocol version 3

Then pass it to Net::SFTP#start like this:

Net::SFTP.start(host, user, { password: password, port: port }, { version: version })