API reference

Table of Contents

• API reference
  • Modules and classes hierarchy
  • Users
  • Control connection
  • Data connection
  • Server (acceptor)
  • Filesystem
  • Extended classes
    • Extended handlers
    • Extended authorizers
    • Extended filesystems
    • Extended servers

pyftpdlib implements the server side of the FTP protocol as defined in RFC-959. This document is intended to serve as a simple API reference of most important classes and functions. After reading this you will probably want to read the tutorial including customization through the use of some example scripts.

Modules and classes hierarchy

pyftpdlib.authorizers
pyftpdlib.authorizers.AuthenticationFailed
pyftpdlib.authorizers.DummyAuthorizer
pyftpdlib.authorizers.UnixAuthorizer
pyftpdlib.authorizers.WindowsAuthorizer
pyftpdlib.handlers
pyftpdlib.handlers.FTPHandler
pyftpdlib.handlers.TLS_FTPHandler
pyftpdlib.handlers.DTPHandler
pyftpdlib.handlers.TLS_DTPHandler
pyftpdlib.handlers.ThrottledDTPHandler
pyftpdlib.filesystems
pyftpdlib.filesystems.FilesystemError
pyftpdlib.filesystems.AbstractedFS
pyftpdlib.filesystems.UnixFilesystem
pyftpdlib.servers
pyftpdlib.servers.FTPServer
pyftpdlib.servers.ThreadedFTPServer
pyftpdlib.servers.MultiprocessFTPServer
pyftpdlib.ioloop
pyftpdlib.ioloop.IOLoop
pyftpdlib.ioloop.Connector
pyftpdlib.ioloop.Acceptor
pyftpdlib.ioloop.AsyncChat

Users

class pyftpdlib.authorizers.DummyAuthorizer

Basic “dummy” authorizer class, suitable for subclassing to create your own custom authorizers. An “authorizer” is a class handling authentications and permissions of the FTP server. It is used inside pyftpdlib.handlers.FTPHandler class for verifying user’s password, getting users home directory, checking user permissions when a filesystem read/write event occurs and changing user before accessing the filesystem. DummyAuthorizer is the base authorizer, providing a platform independent interface for managing “virtual” FTP users. Typically the first thing you have to do is create an instance of this class and start adding ftp users:

>>> from pyftpdlib.authorizers import DummyAuthorizer
>>> authorizer = DummyAuthorizer()
>>> authorizer.add_user('user', 'password', '/home/user', perm='elradfmwMT')
>>> authorizer.add_anonymous('/home/nobody')

add_user(username, password, homedir, perm="elr", msg_login="Login successful.", msg_quit="Goodbye.")

Add a user to the virtual users table. AuthorizerError exception is raised on error conditions such as insufficient permissions or duplicate usernames. Optional perm argument is a set of letters referencing the user’s permissions. Every letter is used to indicate that the access rights the current FTP user has over the following specific actions are granted. The available permissions are the following listed below:

Read permissions:

• "e" = change directory (CWD, CDUP commands)
• "l" = list files (LIST, NLST, STAT, MLSD, MLST, SIZE commands)
• "r" = retrieve file from the server (RETR command)

Write permissions:

• "a" = append data to an existing file (APPE command)
• "d" = delete file or directory (DELE, RMD commands)
• "f" = rename file or directory (RNFR, RNTO commands)
• "m" = create directory (MKD command)
• "w" = store a file to the server (STOR, STOU commands)
• "M" = change file mode / permission (SITE CHMOD command) New in 0.7.0
• "T" = change file modification time (SITE MFMT command) New in 1.5.3

Optional msg_login and msg_quit arguments can be specified to provide customized response strings when user log-in and quit. The perm argument of the add_user() method refers to user’s permissions. Every letter is used to indicate that the access rights the current FTP user has over the following specific actions are granted.

add_anonymous(homedir, **kwargs)

Add an anonymous user to the virtual users table. AuthorizerError exception is raised on error conditions such as insufficient permissions, missing home directory, or duplicate anonymous users. The keyword arguments in kwargs are the same expected by add_user() method: perm, msg_login and msg_quit. The optional perm keyword argument is a string defaulting to “elr” referencing “read-only” anonymous user’s permission. Using a “write” value results in a RuntimeWarning.

override_perm(username, directory, perm, recursive=False)

Override user permissions for a given directory.

validate_authentication(username, password, handler)

Raises pyftpdlib.authorizers.AuthenticationFailed if the supplied username and password doesn’t match the stored credentials.

Changed in 1.0.0: new handler parameter.

Changed in 1.0.0: an exception is now raised for signaling a failed authenticaiton as opposed to returning a bool.

impersonate_user(username, password)

Impersonate another user (noop). It is always called before accessing the filesystem. By default it does nothing. The subclass overriding this method is expected to provide a mechanism to change the current user.

terminate_impersonation(username)

Terminate impersonation (noop). It is always called after having accessed the filesystem. By default it does nothing. The subclass overriding this method is expected to provide a mechanism to switch back to the original user.

remove_user(username)

Remove a user from the virtual user table.

Control connection

class pyftpdlib.handlers.FTPHandler(conn, server)

This class implements the FTP server Protocol Interpreter (see RFC-959), handling commands received from the client on the control channel by calling the command’s corresponding method (e.g. for received command “MKD pathname”, ftp_MKD() method is called with pathname as the argument). All relevant session information are stored in instance variables. conn is the underlying socket object instance of the newly established connection, server is the pyftpdlib.servers.FTPServer class instance. Basic usage simply requires creating an instance of FTPHandler class and specify which authorizer instance it will going to use:

>>> from pyftpdlib.handlers import FTPHandler
>>> handler = FTPHandler
>>> handler.authorizer = authorizer

All relevant session information is stored in class attributes reproduced below and can be modified before instantiating this class:

timeout

The timeout which is the maximum time a remote client may spend between FTP commands. If the timeout triggers, the remote client will be kicked off (defaults to 300 seconds).

New in version 5.0

banner

String sent when client connects (default "pyftpdlib %s ready." %__ver__).

max_login_attempts

Maximum number of wrong authentications before disconnecting (default 3).

permit_foreign_addresses

Whether enable FXP feature (default False).

permit_privileged_ports

Set to True if you want to permit active connections (PORT) over privileged ports (not recommended, default False).

masquerade_address

The “masqueraded” IP address to provide along PASV reply when pyftpdlib is running behind a NAT or other types of gateways. When configured pyftpdlib will hide its local address and instead use the public address of your NAT (default None).

masquerade_address_map

In case the server has multiple IP addresses which are all behind a NAT router, you may wish to specify individual masquerade_addresses for each of them. The map expects a dictionary containing private IP addresses as keys, and their corresponding public (masquerade) addresses as values (defaults to {}). New in version 0.6.0

passive_ports

What ports ftpd will use for its passive data transfers. Value expected is a list of integers (e.g. range(60000, 65535)). When configured pyftpdlib will no longer use kernel-assigned random ports (default None).

use_gmt_times

When True causes the server to report all ls and MDTM times in GMT and not local time (default True). New in version 0.6.0

tcp_no_delay

Controls the use of the TCP_NODELAY socket option which disables the Nagle algorithm resulting in significantly better performances (default True on all platforms where it is supported). New in version 0.6.0

use_sendfile

When True uses sendfile(2) system call to send a file resulting in faster uploads (from server to client). Works on UNIX only and requires pysendfile module to be installed separately.

New in version 0.7.0

auth_failed_timeout

The amount of time the server waits before sending a response in case of failed authentication.

New in version 1.5.0

Follows a list of callback methods that can be overridden in a subclass. For blocking operations read the FAQ on how to run time consuming tasks.

on_connect()

Called when client connects.

New in version 1.0.0

on_disconnect()

Called when connection is closed.

New in version 1.0.0

on_login(username)

Called on user login.

New in version 0.6.0

on_login_failed(username, password)

Called on failed user login.

New in version 0.7.0

on_logout(username)

Called when user logs out due to QUIT or USER issued twice. This is not called if client just disconnects without issuing QUIT first.

New in version 0.6.0

on_file_sent(file)

Called every time a file has been successfully sent. file is the absolute name of that file.

on_file_received(file)

Called every time a file has been successfully received. file is the absolute name of that file.

on_incomplete_file_sent(file)

Called every time a file has not been entirely sent (e.g. transfer aborted by client). file is the absolute name of that file.

New in version 0.6.0

on_incomplete_file_received(file)

Called every time a file has not been entirely received (e.g. transfer aborted by client). file is the absolute name of that file. New in version 0.6.0

Data connection

class pyftpdlib.handlers.DTPHandler(sock_obj, cmd_channel)

This class handles the server-data-transfer-process (server-DTP, see RFC-959) managing all transfer operations regarding the data channel. sock_obj is the underlying socket object instance of the newly established connection, cmd_channel is the pyftpdlib.handlers.FTPHandler class instance.

Changed in version 1.0.0: added ioloop argument.

timeout

The timeout which roughly is the maximum time we permit data transfers to stall for with no progress. If the timeout triggers, the remote client will be kicked off (default 300 seconds).

ac_in_buffer_size

ac_out_buffer_size

The buffer sizes to use when receiving and sending data (both defaulting to 65536 bytes). For LANs you may want this to be fairly large. Depending on available memory and number of connected clients setting them to a lower value can result in better performances.

class pyftpdlib.handlers.ThrottledDTPHandler(sock_obj, cmd_channel)

A pyftpdlib.handlers.DTPHandler subclass which wraps sending and receiving in a data counter and temporarily “sleeps” the channel so that you burst to no more than x Kb/sec average. Use it instead of pyftpdlib.handlers.DTPHandler to set transfer rates limits for both downloads and/or uploads (see the demo script showing the example usage).

read_limit

The maximum number of bytes to read (receive) in one second (defaults to 0 == no limit)

write_limit

The maximum number of bytes to write (send) in one second (defaults to 0 == no limit).

Server (acceptor)

class pyftpdlib.servers.FTPServer(address_or_socket, handler, ioloop=None, backlog=100)

Creates a socket listening on address (an (host, port) tuple) or a pre- existing socket object, dispatching the requests to handler (typically pyftpdlib.handlers.FTPHandler class). Also, starts the asynchronous IO loop. backlog is the maximum number of queued connections passed to socket.listen(). If a connection request arrives when the queue is full the client may raise ECONNRESET.

Changed in version 1.0.0: added ioloop argument.

Changed in version 1.2.0: address can also be a pre-existing socket object.

Changed in version 1.2.0: Added backlog argument.

Changed in version 1.5.4: Support for the context manager protocol was added. Exiting the context manager is equivalent to calling :meth:`close_all`.

>>> from pyftpdlib.servers import FTPServer
>>> address = ('127.0.0.1', 21)
>>> server = FTPServer(address, handler)
>>> server.serve_forever()

It can also be used as a context manager. Exiting the context manager is equivalent to calling close_all().

>>> with FTPServer(address, handler) as server:
...     server.serve_forever()

max_cons

Number of maximum simultaneous connections accepted (default 512).

max_cons_per_ip

Number of maximum connections accepted for the same IP address (default 0 == no limit).

serve_forever(timeout=None, blocking=True, handle_exit=True)

Starts the asynchronous IO loop.

Changed in version 1.0.0: no longer a classmethod; ‘use_poll’ and ‘count’ *parameters were removed. ‘blocking’ and ‘handle_exit’ parameters were *added

close()

Stop accepting connections without disconnecting currently connected clients. server_forever() loop will automatically stop when there are no more connected clients.

close_all()

Disconnect all clients, tell server_forever() loop to stop and wait until it does.

Changed in version 1.0.0: ‘map’ and ‘ignore_all’ parameters were removed.

Filesystem

class pyftpdlib.filesystems.FilesystemError

Exception class which can be raised from within pyftpdlib.filesystems.AbstractedFS in order to send custom error messages to client. New in version 1.0.0

class pyftpdlib.filesystems.AbstractedFS(root, cmd_channel)

A class used to interact with the file system, providing a cross-platform interface compatible with both Windows and UNIX style filesystems where all paths use "/" separator. AbstractedFS distinguishes between “real” filesystem paths and “virtual” ftp paths emulating a UNIX chroot jail where the user can not escape its home directory (example: real “/home/user” path will be seen as “/” by the client). It also provides some utility methods and wraps around all os.* calls involving operations against the filesystem like creating files or removing directories. The contructor accepts two arguments: root which is the user “real” home directory (e.g. ‘/home/user’) and cmd_channel which is the pyftpdlib.handlers.FTPHandler class instance.

Changed in version 0.6.0: root and cmd_channel arguments were added.

root

User’s home directory (“real”). Changed in version 0.7.0: support setattr()

cwd

User’s current working directory (“virtual”).

Changed in version 0.7.0: support setattr()

ftpnorm(ftppath)

Normalize a “virtual” ftp pathname depending on the current working directory (e.g. having "/foo" as current working directory "bar" becomes "/foo/bar").

ftp2fs(ftppath)

Translate a “virtual” ftp pathname into equivalent absolute “real” filesystem pathname (e.g. having "/home/user" as root directory "foo" becomes "/home/user/foo").

fs2ftp(fspath)

Translate a “real” filesystem pathname into equivalent absolute “virtual” ftp pathname depending on the user’s root directory (e.g. having "/home/user" as root directory "/home/user/foo" becomes "/foo".

validpath(path)

Check whether the path belongs to user’s home directory. Expected argument is a “real” filesystem path. If path is a symbolic link it is resolved to check its real destination. Pathnames escaping from user’s root directory are considered not valid (return False).

open(filename, mode)

Wrapper around open() builtin.

mkdir(path)

chdir(path)

rmdir(path)

remove(path)

rename(src, dst)

chmod(path, mode)

stat(path)

lstat(path)

readlink(path)

Wrappers around corresponding os module functions.

isfile(path)

islink(path)

isdir(path)

getsize(path)

getmtime(path)

realpath(path)

lexists(path)

Wrappers around corresponding os.path module functions.

mkstemp(suffix='', prefix='', dir=None, mode='wb')

Wrapper around tempfile.mkstemp.

listdir(path)

Wrapper around os.listdir. It is expected to return a list of unicode strings or a generator yielding unicode strings.

Changed in version 1.6.0: can also return a generator.

Extended classes

We are about to introduces are extensions (subclasses) of the ones explained so far. They usually require third-party modules to be installed separately or are specific for a given Python version or operating system.

Extended handlers

class pyftpdlib.handlers.TLS_FTPHandler(conn, server)

A pyftpdlib.handlers.FTPHandler subclass implementing FTPS (FTP over SSL/TLS) as described in RFC-4217 implementing AUTH, PBSZ and PROT commands. PyOpenSSL module is required to be installed. Example below shows how to setup an FTPS server. Configurable attributes:

certfile

The path to a file which contains a certificate to be used to identify the local side of the connection. This must always be specified, unless context is provided instead.

keyfile

The path of the file containing the private RSA key; can be omittetted if certfile already contains the private key (defaults: None).

ssl_protocol

The desired SSL protocol version to use. This defaults to SSL.SSLv23_METHOD which will negotiate the highest protocol that both the server and your installation of OpenSSL support.

ssl_options

specific OpenSSL options. These default to: SSL.OP_NO_SSLv2 | SSL.OP_NO_SSLv3 | SSL.OP_NO_COMPRESSION disabling SSLv2 and SSLv3 versions and SSL compression algorithm which are considered insecure. Can be set to None in order to improve compatibilty with older (insecure) FTP clients.

New in version 1.6.0.

ssl_context

A SSL.Context instance which was previously configured. If specified ssl_protocol and ssl_options parameters will be ignored.

tls_control_required

When True requires SSL/TLS to be established on the control channel, before logging in. This means the user will have to issue AUTH before USER/PASS (default False).

tls_data_required

When True requires SSL/TLS to be established on the data channel. This means the user will have to issue PROT before PASV or PORT (default False).

Extended authorizers

class pyftpdlib.authorizers.UnixAuthorizer(global_perm="elradfmwMT", allowed_users=None, rejected_users=None, require_valid_shell=True, anonymous_user=None, msg_login="Login successful.", msg_quit="Goodbye.")

Authorizer which interacts with the UNIX password database. Users are no longer supposed to be explicitly added as when using pyftpdlib.authorizers.DummyAuthorizer. All FTP users are the same defined on the UNIX system so if you access on your system by using "john" as username and "12345" as password those same credentials can be used for accessing the FTP server as well. The user home directories will be automatically determined when user logins. Every time a filesystem operation occurs (e.g. a file is created or deleted) the id of the process is temporarily changed to the effective user id and whether the operation will succeed depends on user and file permissions. This is why full read and write permissions are granted by default in the class constructors.

global_perm is a series of letters referencing the users permissions; defaults to “elradfmwMT” which means full read and write access for everybody (except anonymous). allowed_users and rejected_users options expect a list of users which are accepted or rejected for authenticating against the FTP server; defaults both to [] (no restrictions). require_valid_shell denies access for those users which do not have a valid shell binary listed in /etc/shells. If /etc/shells cannot be found this is a no-op. anonymous user is not subject to this option, and is free to not have a valid shell defined. Defaults to True (a valid shell is required for login). anonymous_user can be specified if you intend to provide anonymous access. The value expected is a string representing the system user to use for managing anonymous sessions; defaults to None (anonymous access disabled). Note that in order to use this class super user privileges are required.

New in version 0.6.0

override_user(username=None, password=None, homedir=None, perm=None, anonymous_user=None, msg_login=None, msg_quit=None)

Overrides one or more options specified in the class constructor for a specific user. Example:

>>> from pyftpdlib.authorizers import UnixAuthorizer
>>> auth = UnixAuthorizer(rejected_users=["root"])
>>> auth = UnixAuthorizer(allowed_users=["matt", "jay"])
>>> auth = UnixAuthorizer(require_valid_shell=False)
>>> auth.override_user("matt", password="foo", perm="elr")

class pyftpdlib.authorizers.WindowsAuthorizer(global_perm="elradfmwMT", allowed_users=None, rejected_users=None, anonymous_user=None, anonymous_password="", msg_login="Login successful.", msg_quit="Goodbye.")

Same as pyftpdlib.authorizers.UnixAuthorizer except for anonymous_password argument which must be specified when defining the anonymous_user. Also requires_valid_shell option is not available. In order to use this class pywin32 extension must be installed.

New in version 0.6.0

Extended filesystems

class pyftpdlib.filesystems.UnixFilesystem(root, cmd_channel)

Represents the real UNIX filesystem. Differently from pyftpdlib.filesystems.AbstractedFS the client will login into /home/<username> and will be able to escape its home directory and navigate the real filesystem. Use it in conjuction with pyftpdlib.authorizers.UnixAuthorizer to implement a “real” UNIX FTP server (see demo/unix_ftpd.py).

New in version 0.6.0

Extended servers

class pyftpdlib.servers.ThreadedFTPServer(address_or_socket, handler, ioloop=None, backlog=5)

A modified version of base pyftpdlib.servers.FTPServer class which spawns a thread every time a new connection is established. Differently from base FTPServer class, the handler will be free to block without hanging the whole IO loop.

New in version 1.0.0

Changed in 1.2.0: added ioloop parameter; address can also be a pre-existing *socket.

class pyftpdlib.servers.MultiprocessFTPServer(address_or_socket, handler, ioloop=None, backlog=5)

A modified version of base pyftpdlib.servers.FTPServer class which spawns a process every time a new connection is established. Differently from base FTPServer class, the handler will be free to block without hanging the whole IO loop.

New in version 1.0.0

Changed in 1.2.0: added ioloop parameter; address can also be a pre-existing socket.

Availability: POSIX + Python >= 2.6