Add Net::FTP#features and Net::FTP#option

Patch by darkphnx (Dan Wentworth) .  Thanks!
[Feature #15964]

NEWS

@@ -254,6 +254,10 @@ IRB::
 
   * Enable auto indent and save/load history by default.
 
+Net::FTP::
+
+  * Add features and options.  [Feature #15964]
+
 Net::IMAP::
 
   * Add Server Name Indication (SNI) support.  [Feature #15594]

lib/net/ftp.rb

@@ -1297,6 +1297,41 @@ module Net
       voidcmd(cmd)
     end
 
+    #
+    # Issues a FEAT command
+    #
+    # Returns an array of supported optional features
+    #
+    def features
+      resp = sendcmd("FEAT")
+      if !resp.start_with?("211")
+        raise FTPReplyError, resp
+      end
+
+      feats = []
+      resp.split("\n").each do |line|
+        next if !line.start_with?(' ') # skip status lines
+
+        feats << line.strip
+      end
+
+      return feats
+    end
+
+    #
+    # Issues an OPTS command
+    # - name Should be the name of the option to set
+    # - params is any optional parameters to supply with the option
+    #
+    # example: option('UTF8', 'ON') => 'OPTS UTF8 ON'
+    #
+    def option(name, params = nil)
+      cmd = "OPTS #{name}"
+      cmd += " #{params}" if params
+
+      voidcmd(cmd)
+    end
+
     #
     # Closes the connection.  Further operations are impossible until you open
     # a new connection with #connect.

test/net/ftp/test_ftp.rb

@@ -1530,6 +1530,102 @@ EOF
     end
   end
 
+  def test_features
+    commands = []
+    server = create_ftp_server { |sock|
+      sock.print("220 (test_ftp).\r\n")
+      commands.push(sock.gets)
+      sock.print("211-Features\r\n")
+      sock.print(" LANG EN*\r\n")
+      sock.print(" UTF8\r\n")
+      sock.print("211 End\r\n")
+    }
+    begin
+      begin
+        ftp = Net::FTP.new
+        ftp.connect(SERVER_ADDR, server.port)
+        assert_equal(['LANG EN*', 'UTF8'], ftp.features)
+        assert_equal("FEAT\r\n", commands.shift)
+        assert_equal(nil, commands.shift)
+      ensure
+        ftp.close if ftp
+      end
+    ensure
+      server.close
+    end
+  end
+
+  def test_features_not_implemented
+    commands = []
+    server = create_ftp_server { |sock|
+      sock.print("220 (test_ftp).\r\n")
+      commands.push(sock.gets)
+      sock.print("502 Not Implemented\r\n")
+    }
+    begin
+      begin
+        ftp = Net::FTP.new
+        ftp.connect(SERVER_ADDR, server.port)
+        assert_raise(Net::FTPPermError) do
+          ftp.features
+        end
+        assert_equal("FEAT\r\n", commands.shift)
+        assert_equal(nil, commands.shift)
+      ensure
+        ftp.close if ftp
+      end
+    ensure
+      server.close
+    end
+
+  end
+
+  def test_option
+    commands = []
+    server = create_ftp_server { |sock|
+      sock.print("220 (test_ftp)\r\n")
+      commands.push(sock.gets)
+      sock.print("200 OPTS UTF8 command successful\r\n")
+    }
+    begin
+      begin
+        ftp = Net::FTP.new
+        ftp.connect(SERVER_ADDR, server.port)
+        ftp.option("UTF8", "ON")
+        assert_equal("OPTS UTF8 ON\r\n", commands.shift)
+        assert_equal(nil, commands.shift)
+      ensure
+        ftp.close if ftp
+      end
+    ensure
+      server.close
+    end
+  end
+
+  def test_option_not_implemented
+    commands = []
+    server = create_ftp_server { |sock|
+      sock.print("220 (test_ftp)\r\n")
+      commands.push(sock.gets)
+      sock.print("502 Not implemented\r\n")
+    }
+    begin
+      begin
+        ftp = Net::FTP.new
+        ftp.connect(SERVER_ADDR, server.port)
+        assert_raise(Net::FTPPermError) do
+          ftp.option("UTF8", "ON")
+        end
+        assert_equal("OPTS UTF8 ON\r\n", commands.shift)
+        assert_equal(nil, commands.shift)
+      ensure
+        ftp.close if ftp
+      end
+    ensure
+      server.close
+    end
+  end
+
   def test_mlst
     commands = []
     server = create_ftp_server { |sock|