Fix Transmit client treating a successful PASV response as failure

[michalc]

This fixes PASV connections on the Transmit client, that doesn't seem to handle the multiline response. An example transcript is below.

**********

Date/Time: 2018-11-01 16:37:39 +0000

1: Transmit 5.2.1 (x86_64) Session Transcript [Version 10.13.5 (Build 17F77)] (01/11/2018, 16:37)
1: LibNcFTP 3.2.3 (July 23, 2009) compiled for UNIX
1: 220: welcome
1: Connected to 127.0.01.
1: Cmd: USER myu
1: 331: password required
1: Cmd: PASS xxxxxxxx
1: 230: normal login
1: Cmd: TYPE A
1: 200: 
1: Logged in to 127.0.01 as myu.
1: Cmd: SYST
1: 215: UNIX Type: L8
1: Cmd: FEAT
1: 502: 'feat' not implemented
1: Cmd: PWD
1: 257: "/"
1: Cmd: PASV
1: Cannot parse PASV response: listen socket created
1: 227: listen socket created
1:      (0,0,0,0,15,161)
1: Passive mode refused.
1: Connection falling back to port (PORT) mode.
1: Cmd: PORT 127,0,0,1,243,198
1: 502: 'port' not implemented
1: Cmd: PORT 127,0,0,1,243,199
1: 502: 'port' not implemented
1: Cmd: PORT 127,0,0,1,243,200
1: 502: 'port' not implemented
1: Cmd: PORT 127,0,0,1,243,201
1: 502: 'port' not implemented
1: Canceling…
1: Disconnecting from server…
1: Cmd: QUIT
1: 221: bye

[pohmelie]

I don't get what this solves and why multiline is a problem?

[michalc]

@pohmelie I have amended the PR description with more details

[codecov]

Codecov Report

Merging #85 into master will decrease coverage by 0.05%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master      #85      +/-   ##
==========================================
- Coverage   94.04%   93.98%   -0.06%     
==========================================
  Files           7        7              
  Lines        1695     1695              
==========================================
- Hits         1594     1593       -1     
- Misses        101      102       +1

Impacted Files	Coverage Δ
aioftp/server.py	96.92% <66.66%> (-0.15%)	⬇️

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[pohmelie]

I think at first you should try to get feedback from Transmit devs via e-mail (https://library.panic.com/transmit/). Sadly, their GOLD STANDARD app have no bugtracker.

227-listen socket created
227 (127,0,0,1,154,21)

Response is valid and works fine with all tools I tried.

[michalc]

I have now emailed them, thanks.

[pohmelie]

@michalc any news?

[tomharvey]

I'm getting the same error - but not just in Transmit (also seeing an error while using Cyberduck). Also, the PR from @michalc doesn't seem to fix the issue; still Cannot parse PASV response: listen socket created.

Maybe this should be an issue instead of in here?

I am using 0.0.0.0 as the bind IP, and then connecting to 127.0.0.1 - is this maybe related to passive not liking the local IP addresses? I can investigate more next weekend..

[pohmelie]

I can investigate more next weekend

It will be good if you have time of course.