uftpd: small FTP server for ESP8266, ESP32 and Pyboard D

Intro

Capabilities

• The minimun necessary subset of commands are supported: STOR, RETR, RNFR, RNTO rename, DELE, MDTM, RMD, MKD PWD, CDUP:cd .., SIZE f:filesize, PASV:passive mode, PORT p, LIST(aka NLST), SITE and QUIT.

• Ommitted commands required as per RF5797 are ABOR, ACCT, ALLO, APPE, MODE, REIN, RESTart, STRU and HELP.

• Recognized but ignored: USER and PASS.

• With the SITE command, the code in the payload MUST NOT be blocking, because that will block the device.

• No user authentication. Any user may log in without a password.

• Binary (aka IMAGE) mode only i.e. no translations of NL to/from CRLF (Would be helpful going to/from MS Windows.)

• Limited multi-session support. The server accepts multiple connections, but only one session command at a time is served while the other sessions receive a 'busy' response, which still allows interleaved actions.

• While the ftp server runs in the background and servicing requests, foreground tasks should not be run.

• ESP32 server is supported from version='v1.9.3-575 on. That version which introduced webrepl.

Using

Due to the size limitations for ESP8266, ftpd either has to be integrated into the flash image as frozen bytecode, by placing it into the esp8266/modules folder and performing a rebuild, or compiled into bytecode using mpy-cross and loaded as an .mpy file. The frozen bytecode variant is preferred.

Starting/Stopping

Start the daemon using: import uftpd

The service will be started at port 21 in silent mode.

Stop the daemon using: uftpd.stop()

To start with options use: uftpd.start([port = 21][, verbose = level])

port is the port number (default 21) verbose >0 will print commands and activity messages and OSError if one occurs.

To restart with different options use: uftd.restart([port = 21][, verbose = level])

Compatability

The server works well with most dedicated ftp clients, and most browsers and file managers. These are test results with an arbitrary selected set:

Linux

• ftp: works for file & directory operations including support for the m* commands
• filezilla: including loading into the editor & saving back. Take care to limit the number of data session to 1.
• Nautilus: works mostly, including loading into the editor & saving back. Copying multiple files at once to the esp8266 fails, because nautilus tries to open multiple sessions for that purpose. Configure Nautilus with dconf-editor to show directory count for local dirs only. Once mounted, you can even open a terminal at that spot. The path is something like: /run/user/1000/gvfs/ftp:host=x.y.y.z.
• Thunar: works fine, including loading & saving of files. directly into e.g. an editor & saving back.
• Dolphin, Konqueror: work fine most of the time, including loading directly into e.g. an editor & saving back.
• Chrome, Firefox: view/navigate directories & and view files

Mac OS X, various Versions

• Linux: ftp works
• Chrome, Firefox: view/navigate directories & and view files
• FileZilla, Cyberduck: Full operation, once proper configured (see above). Configure Cyberduck to transfer data in the command session.
• Finder: Fails. It connects, but then locks in the attempt to display the top level directory
• Mountainduck: Works well

Windows 10 (and Windows XP)

• ftp: supported.
• File explorer: view/navigate directories & and copy files. Windows explorer does not always release the connection when it is closed, which just results in a silent connection, which is closed latest when Windows is shut down.
• FileZilla, Cyberduck: Full operation, once proper configured (see above). Configure Cyberduck to transfer data in the command session.
• WinSCP: works fine
• NppFTP - FTP extension to Notepad++: Works fine and is very convenient.
• Mountainduck: Works to some extent, but sometimes stumbles and takes a long time to open a file.

Android

• ftp inside the terminal emulator termux: full operation.
• ftp-express
• Chrome: view/navigate directories & and view files

IOS 9.1

• FTP Client lite: works

Windows 10 mobile

• Metro file manager: Works with file/directory view & navigate, file download, file upload, file delete, file rename. Slow and chaotic sequence of FTP commands.

Conclusion: All dedicated ftp clients work fine, and most of the file managers.

Trouble Shooting

uftpd supports verbose=1.

The only trouble observed was clients not releasing the connections. Check by the value of uftp.client_list, which should be empty if no client is connected, or by issuing the command rstat in ftp, which shows the number of connected clients. Restart the server with uftpd.restart(). If uftd.client_busy is True when no client is connected, then restart the server with with uftpd.restart().

Files

• uftpd.py: for ESP8266 and ESP32 from version='v1.9.3-575 onward.

• ftpd.py: Simple version, works in foreground to be used with all Micorpython versions. Terminates when the client closes the session. Only a single session is supported. def ftpserver(port=21, timeout=None):

• ftpd_thread.py Includes: +++++++ def ftpserver(not_stop_on_quit): ... try: import _thread _thread.start_new_thread(ftpserver, ((True,))) except: ftpserver(False) ++++++

• ftpd_pycom.py

• README.md:

Attribution

This version, 2022-04-06, comes from the github repository of robert-hh/FTP-Server-for-ESP8266-ESP32-and-PYBD

uftpd.py
JD Smith Use a preallocated buffer, improve error handling, MDTM and SITE support. Jan Wieck Use separate FTP servers per socket for STAtion + AccessPoint mode.

Based on the work of RobertHH, chrisgp - Christopher Popp and pfalcon - Paul Sokolovsky RobertHH put all these pieces together and assembled an uftpd.py script, which runs in background and acts as ftp server. Christopher made a first uftp server script, which runs in foreground. Paul made webrepl with the framework for background operations, which then was used also by Christopher to implement his utelnetsever code. /*