"""An FTP client class and some helper functions.

Based on RFC 959: File Transfer Protocol (FTP), by J. Postel and J. Reynolds

Example:

>>> from ftplib import FTP

>>> ftp = FTP('ftp.python.org') # connect to host, default port

>>> ftp.login() # default, i.e.: user anonymous, passwd anonymous@

'230 Guest login ok, access restrictions apply.'

>>> ftp.retrlines('LIST') # list directory contents

total 9

drwxr-xr-x   8 root     wheel        1024 Jan  3  1994 .

drwxr-xr-x   8 root     wheel        1024 Jan  3  1994 ..

drwxr-xr-x   2 root     wheel        1024 Jan  3  1994 bin

drwxr-xr-x   2 root     wheel        1024 Jan  3  1994 etc

d-wxrwxr-x   2 ftp      wheel        1024 Sep  5 13:43 incoming

drwxr-xr-x   2 root     wheel        1024 Nov 17  1993 lib

drwxr-xr-x   6 1094     wheel        1024 Sep 13 19:07 pub

drwxr-xr-x   3 root     wheel        1024 Jan  3  1994 usr

-rw-r--r--   1 root     root          312 Aug  1  1994 welcome.msg

'226 Transfer complete.'

>>> ftp.quit()

'221 Goodbye.'

>>>

A nice test that reveals some of the network dialogue would be:

python ftplib.py -d localhost -l -p -l

"""

#

# Changes and improvements suggested by Steve Majewski.

# Modified by Jack to work on the mac.

# Modified by Siebren to support docstrings and PASV.

#

import os

import sys

# Import SOCKS module if it exists, else standard socket module socket

try:

    import SOCKS; socket = SOCKS; del SOCKS # import SOCKS as socket

    from socket import getfqdn; socket.getfqdn = getfqdn; del getfqdn

except ImportError:

    import socket

__all__ = ["FTP","Netrc"]

# Magic number from <socket.h>

MSG_OOB = 0x1                           # Process data out of band

# The standard FTP server control port

FTP_PORT = 21

# Exception raised when an error or invalid response is received

class Error(Exception): pass

class error_reply(Error): pass          # unexpected [123]xx reply

class error_temp(Error): pass           # 4xx errors

class error_perm(Error): pass           # 5xx errors

class error_proto(Error): pass          # response does not begin with [1-5]

# All exceptions (hopefully) that may be raised here and that aren't

# (always) programming errors on our side

all_errors = (Error, socket.error, IOError, EOFError)

# Line terminators (we always output CRLF, but accept any of CRLF, CR, LF)

CRLF = '\r\n'

# The class itself

class FTP:

    '''An FTP client class.

    To create a connection, call the class using these argument:

            host, user, passwd, acct

    These are all strings, and have default value ''.

    Then use self.connect() with optional host and port argument.

    To download a file, use ftp.retrlines('RETR ' + filename),

    or ftp.retrbinary() with slightly different arguments.

    To upload a file, use ftp.storlines() or ftp.storbinary(),

    which have an open file as argument (see their definitions

    below for details).

    The download/upload functions first issue appropriate TYPE

    and PORT or PASV commands.

'''

    debugging = 0

    host = ''

    port = FTP_PORT

    sock = None

    file = None

    welcome = None

    passiveserver = 1

    # Initialization method (called by class instantiation).

    # Initialize host to localhost, port to standard ftp port

    # Optional arguments are host (for connect()),

    # and user, passwd, acct (for login())

    def __init__(self, host='', user='', passwd='', acct=''):

        if host:

            self.connect(host)

            if user: self.login(user, passwd, acct)

    def connect(self, host = '', port = 0):

        '''Connect to host.  Arguments are:

        - host: hostname to connect to (string, default previous host)

        - port: port to connect to (integer, default previous port)'''

        if host: self.host = host

        if port: self.port = port

        msg = "getaddrinfo returns an empty list"

        for res in socket.getaddrinfo(self.host, self.port, 0, socket.SOCK_STREAM):

            af, socktype, proto, canonname, sa = res

            try:

                self.sock = socket.socket(af, socktype, proto)

                self.sock.connect(sa)

            except socket.error, msg:

                if self.sock:

                    self.sock.close()

                self.sock = None

                continue

            break

        if not self.sock:

            raise socket.error, msg

        self.af = af

        self.file = self.sock.makefile('rb')

        self.welcome = self.getresp()

        return self.welcome

    def getwelcome(self):

        '''Get the welcome message from the server.

        (this is read and squirreled away by connect())'''

        if self.debugging:

            print '*welcome*', self.sanitize(self.welcome)

        return self.welcome

    def set_debuglevel(self, level):

        '''Set the debugging level.

        The required argument level means:

        0: no debugging output (default)

        1: print commands and responses but not body text etc.

        2: also print raw lines read and sent before stripping CR/LF'''

        self.debugging = level

    debug = set_debuglevel

    def set_pasv(self, val):

        '''Use passive or active mode for data transfers.

        With a false argument, use the normal PORT mode,

        With a true argument, use the PASV command.'''

        self.passiveserver = val

    # Internal: "sanitize" a string for printing

    def sanitize(self, s):

        if s[:5] == 'pass ' or s[:5] == 'PASS ':

            i = len(s)

            while i > 5 and s[i-1] in '\r\n':

                i = i-1

            s = s[:5] + '*'*(i-5) + s[i:]

        return repr(s)

    # Internal: send one line to the server, appending CRLF

    def putline(self, line):

        line = line + CRLF

        if self.debugging > 1: print '*put*', self.sanitize(line)

        self.sock.sendall(line)

    # Internal: send one command to the server (through putline())

    def putcmd(self, line):

        if self.debugging: print '*cmd*', self.sanitize(line)

        self.putline(line)

    # Internal: return one line from the server, stripping CRLF.

    # Raise EOFError if the connection is closed

    def getline(self):

        line = self.file.readline()

        if self.debugging > 1:

            print '*get*', self.sanitize(line)

        if not line: raise EOFError

        if line[-2:] == CRLF: line = line[:-2]

        elif line[-1:] in CRLF: line = line[:-1]

        return line

    # Internal: get a response from the server, which may possibly

    # consist of multiple lines.  Return a single string with no

    # trailing CRLF.  If the response consists of multiple lines,

    # these are separated by '\n' characters in the string

    def getmultiline(self):

        line = self.getline()

        if line[3:4] == '-':

            code = line[:3]

            while 1:

                nextline = self.getline()

                line = line + ('\n' + nextline)

                if nextline[:3] == code and \

                        nextline[3:4] != '-':

                    break

        return line

    # Internal: get a response from the server.

    # Raise various errors if the response indicates an error

    def getresp(self):

        resp = self.getmultiline()

        if self.debugging: print '*resp*', self.sanitize(resp)

        self.lastresp = resp[:3]

        c = resp[:1]

        if c in ('1', '2', '3'):

            return resp

        if c == '4':

            raise error_temp, resp

        if c == '5':

            raise error_perm, resp

        raise error_proto, resp

    def voidresp(self):

        """Expect a response beginning with '2'."""

        resp = self.getresp()

        if resp[0] != '2':

            raise error_reply, resp

        return resp

    def abort(self):

        '''Abort a file transfer.  Uses out-of-band data.

        This does not follow the procedure from the RFC to send Telnet

        IP and Synch; that doesn't seem to work with the servers I've

        tried.  Instead, just send the ABOR command as OOB data.'''

        line = 'ABOR' + CRLF

        if self.debugging > 1: print '*put urgent*', self.sanitize(line)

        self.sock.sendall(line, MSG_OOB)

        resp = self.getmultiline()

        if resp[:3] not in ('426', '226'):

            raise error_proto, resp

    def sendcmd(self, cmd):

        '''Send a command and return the response.'''

        self.putcmd(cmd)

        return self.getresp()

    def voidcmd(self, cmd):

        """Send a command and expect a response beginning with '2'."""

        self.putcmd(cmd)

        return self.voidresp()

    def sendport(self, host, port):

        '''Send a PORT command with the current host and the given

        port number.

        '''

        hbytes = host.split('.')

        pbytes = [repr(port/256), repr(port%256)]

        bytes = hbytes + pbytes

        cmd = 'PORT ' + ','.join(bytes)

        return self.voidcmd(cmd)

    def sendeprt(self, host, port):

        '''Send a EPRT command with the current host and the given port number.'''

        af = 0

        if self.af == socket.AF_INET:

            af = 1

        if self.af == socket.AF_INET6:

            af = 2

        if af == 0:

            raise error_proto, 'unsupported address family'

        fields = ['', repr(af), host, repr(port), '']

        cmd = 'EPRT ' + '|'.join(fields)

        return self.voidcmd(cmd)

    def makeport(self):

        '''Create a new socket and send a PORT command for it.'''

        msg = "getaddrinfo returns an empty list"

        sock = None

        for res in socket.getaddrinfo(None, 0, self.af, socket.SOCK_STREAM, 0, socket.AI_PASSIVE):

            af, socktype, proto, canonname, sa = res

            try:

                sock = socket.socket(af, socktype, proto)

                sock.bind(sa)

            except socket.error, msg:

                if sock:

                    sock.close()

                sock = None

                continue

            break

        if not sock:

            raise socket.error, msg

        sock.listen(1)

        port = sock.getsockname()[1] # Get proper port

        host = self.sock.getsockname()[0] # Get proper host

        if self.af == socket.AF_INET:

            resp = self.sendport(host, port)

        else:

            resp = self.sendeprt(host, port)

        return sock

    def makepasv(self):

        if self.af == socket.AF_INET:

            host, port = parse227(self.sendcmd('PASV'))

        else:

            host, port = parse229(self.sendcmd('EPSV'), self.sock.getpeername())

        return host, port

    def ntransfercmd(self, cmd, rest=None):

        """Initiate a transfer over the data connection.

        If the transfer is active, send a port command and the

        transfer command, and accept the connection.  If the server is

        passive, send a pasv command, connect to it, and start the

        transfer command.  Either way, return the socket for the

        connection and the expected size of the transfer.  The

        expected size may be None if it could not be determined.

        Optional `rest' argument can be a string that is sent as the

        argument to a RESTART command.  This is essentially a server

        marker used to tell the server to skip over any data up to the

        given marker.

        """

        size = None

        if self.passiveserver:

            host, port = self.makepasv()

            af, socktype, proto, canon, sa = socket.getaddrinfo(host, port, 0, socket.SOCK_STREAM)[0]

            conn = socket.socket(af, socktype, proto)

            conn.connect(sa)

            if rest is not None:

                self.sendcmd("REST %s" % rest)

            resp = self.sendcmd(cmd)

            # Some servers apparently send a 200 reply to

            # a LIST or STOR command, before the 150 reply

            # (and way before the 226 reply). This seems to

            # be in violation of the protocol (which only allows

            # 1xx or error messages for LIST), so we just discard

            # this response.

            if resp[0] == '2':

                resp = self.getresp()

            if resp[0] != '1':

                raise error_reply, resp

        else:

            sock = self.makeport()

            if rest is not None:

                self.sendcmd("REST %s" % rest)

            resp = self.sendcmd(cmd)

            # See above.

            if resp[0] == '2':

                resp = self.getresp()

            if resp[0] != '1':

                raise error_reply, resp

            conn, sockaddr = sock.accept()

        if resp[:3] == '150':

            # this is conditional in case we received a 125

            size = parse150(resp)

        return conn, size

    def transfercmd(self, cmd, rest=None):

        """Like ntransfercmd() but returns only the socket."""

        return self.ntransfercmd(cmd, rest)[0]

    def login(self, user = '', passwd = '', acct = ''):

        '''Login, default anonymous.'''

        if not user: user = 'anonymous'

        if not passwd: passwd = ''

        if not acct: acct = ''

        if user == 'anonymous' and passwd in ('', '-'):

            # If there is no anonymous ftp password specified

            # then we'll just use anonymous@

            # We don't send any other thing because:

            # - We want to remain anonymous

            # - We want to stop SPAM

            # - We don't want to let ftp sites to discriminate by the user,

            #   host or country.

            passwd = passwd + 'anonymous@'

        resp = self.sendcmd('USER ' + user)

        if resp[0] == '3': resp = self.sendcmd('PASS ' + passwd)

        if resp[0] == '3': resp = self.sendcmd('ACCT ' + acct)

        if resp[0] != '2':

            raise error_reply, resp

        return resp

    def retrbinary(self, cmd, callback, blocksize=8192, rest=None):

        """Retrieve data in binary mode.

        `cmd' is a RETR command.  `callback' is a callback function is

        called for each block.  No more than `blocksize' number of

        bytes will be read from the socket.  Optional `rest' is passed

        to transfercmd().

        A new port is created for you.  Return the response code.

        """

        self.voidcmd('TYPE I')

        conn = self.transfercmd(cmd, rest)

        while 1:

            data = conn.recv(blocksize)

            if not data:

                break

            callback(data)

        conn.close()

        return self.voidresp()

    def retrlines(self, cmd, callback = None):

        '''Retrieve data in line mode.

        The argument is a RETR or LIST command.

        The callback function (2nd argument) is called for each line,

        with trailing CRLF stripped.  This creates a new port for you.

        print_line() is the default callback.'''

        if callback is None: callback = print_line

        resp = self.sendcmd('TYPE A')

        conn = self.transfercmd(cmd)

        fp = conn.makefile('rb')

        while 1:

            line = fp.readline()

            if self.debugging > 2: print '*retr*', repr(line)

            if not line:

                break

            if line[-2:] == CRLF:

                line = line[:-2]

            elif line[-1:] == '\n':

                line = line[:-1]

            callback(line)

        fp.close()

        conn.close()

        return self.voidresp()

    def storbinary(self, cmd, fp, blocksize=8192):

        '''Store a file in binary mode.'''

        self.voidcmd('TYPE I')

        conn = self.transfercmd(cmd)

        while 1:

            buf = fp.read(blocksize)

            if not buf: break

            conn.sendall(buf)

        conn.close()

        return self.voidresp()

    def storlines(self, cmd, fp):

        '''Store a file in line mode.'''

        self.voidcmd('TYPE A')

        conn = self.transfercmd(cmd)

        while 1:

            buf = fp.readline()

            if not buf: break

            if buf[-2:] != CRLF:

                if buf[-1] in CRLF: buf = buf[:-1]

                buf = buf + CRLF

            conn.sendall(buf)

        conn.close()

        return self.voidresp()

    def acct(self, password):

        '''Send new account name.'''

        cmd = 'ACCT ' + password

        return self.voidcmd(cmd)

    def nlst(self, *args):

        '''Return a list of files in a given directory (default the current).'''

        cmd = 'NLST'

        for arg in args:

            cmd = cmd + (' ' + arg)

        files = []

        self.retrlines(cmd, files.append)

        return files

    def dir(self, *args):

        '''List a directory in long form.

        By default list current directory to stdout.

        Optional last argument is callback function; all

        non-empty arguments before it are concatenated to the

        LIST command.  (This *should* only be used for a pathname.)'''

        cmd = 'LIST'

        func = None

        if args[-1:] and type(args[-1]) != type(''):

            args, func = args[:-1], args[-1]

        for arg in args:

            if arg:

                cmd = cmd + (' ' + arg)

        self.retrlines(cmd, func)

    def rename(self, fromname, toname):

        '''Rename a file.'''

        resp = self.sendcmd('RNFR ' + fromname)

        if resp[0] != '3':

            raise error_reply, resp

        return self.voidcmd('RNTO ' + toname)

    def delete(self, filename):

        '''Delete a file.'''

        resp = self.sendcmd('DELE ' + filename)

        if resp[:3] in ('250', '200'):

            return resp

        elif resp[:1] == '5':

            raise error_perm, resp

        else:

            raise error_reply, resp

    def cwd(self, dirname):

        '''Change to a directory.'''

        if dirname == '..':

            try:

                return self.voidcmd('CDUP')

            except error_perm, msg:

                if msg.args[0][:3] != '500':

                    raise

        elif dirname == '':

            dirname = '.'  # does nothing, but could return error

        cmd = 'CWD ' + dirname

        return self.voidcmd(cmd)

    def size(self, filename):

        '''Retrieve the size of a file.'''

        # Note that the RFC doesn't say anything about 'SIZE'

        resp = self.sendcmd('SIZE ' + filename)

        if resp[:3] == '213':

            s = resp[3:].strip()

            try:

                return int(s)

            except (OverflowError, ValueError):

                return long(s)

    def mkd(self, dirname):

        '''Make a directory, return its full pathname.'''

        resp = self.sendcmd('MKD ' + dirname)

        return parse257(resp)

    def rmd(self, dirname):

        '''Remove a directory.'''

        return self.voidcmd('RMD ' + dirname)

    def pwd(self):

        '''Return current working directory.'''