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rubynet-ftp

Why can't Net::FTP connect to server?

I am trying to create a script to list and download data from a FTP server with Ruby. I am new to Ruby so I looked for documentation how to use Net::FTP. I have trouble understanding why this doesn't work:

require 'net/ftp'

server = "ftp.server.com"
user = "myuser"
password = "mypassword"


Net::FTP.open(server, user, password) do |ftp|
        files = ftp.chdir('mydirectory/')
        files = ftp.list
        puts "list out of directory:"
        puts files
end

That doesn't work, returning this error:

/home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:298:in `getresp': 425 >Failed to establish connection. (Net::FTPTempError)
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:325:in `block in sendcmd'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:323:in `sendcmd'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:402:in `transfercmd'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:478:in `block (2 levels) in retrlines'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:178:in `with_binary'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:477:in `block in retrlines'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:476:in `retrlines'
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:722:in `list'
    from test_ftp.rb:10:in `block in '
    from /home/adhown/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/ftp.rb:116:in `open'
    from test_ftp.rb:8:in `'

Can anyone explain what's wrong with my script?

Solution

  • Your code works fine for me. I suspect problem could be because of Net::FTP connection mode, which is by default active. Try connecting using passive mode, following code sample -

    ftp = Net::FTP.new(server)
ftp.passive = true
ftp.login user, password
files = ftp.chdir('mydirectory/')
files = ftp.list
puts "list out of directory:"
puts files
ftp.close

    And if you're curious, following is the difference (from wikipedia) between active and passive modes.

    1. In Active mode, the client creates a TCP control connection to the server and sends the server the client's IP address and an arbitrary client port number, and then waits until the server initiates the data connection over TCP to that client IP address and client port number. In situations where the client is behind a firewall and unable to accept incoming TCP connections, passive mode may be used.
    2. In Passive mode, the client uses the control connection to send a PASV command to the server and then receives a server IP address and server port number from the server which the client then uses to open a data connection from an arbitrary client port to the server IP address and server port number received.