EuroCD 3/EuroCD 3.iso/Programming/Python1.4_Source/Lib/ftplib.py

Python Source | 1998-06-24 | 15.8 KB | 547 lines

'''An FTP client class, and some helper functions.
Based on RFC 959: File Transfer Protocol
(FTP), by J. Postel and J. Reynolds

Changes and improvements suggested by Steve Majewski.
Modified by Jack to work on the mac.
Modified by Siebren to support docstrings and PASV.


Example:

>>> from ftplib import FTP
>>> ftp = FTP('ftp.python.org') # connect to host, default port
>>> ftp.login() # default, i.e.: user anonymous, passwd user@hostname
>>> 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
>>> ftp.quit()
>>>

A nice test that reveals some of the network dialogue would be:
python ftplib.py -d localhost -l -p -l
'''


import os
import sys
import string

# Import SOCKS module if it exists, else standard socket module socket
try:
    import SOCKS; socket = SOCKS
except ImportError:
    import socket


# 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
error_reply = 'ftplib.error_reply'    # unexpected [123]xx reply
error_temp = 'ftplib.error_temp'    # 4xx errors
error_perm = 'ftplib.error_perm'    # 5xx errors
error_proto = 'ftplib.error_proto'    # 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_reply, error_temp, error_perm, error_proto, \
          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.
'''

    # 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 = ''):
        # Initialize the instance to something mostly harmless
        self.debugging = 0
        self.host = ''
        self.port = FTP_PORT
        self.sock = None
        self.file = None
        self.welcome = None
        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
        self.passiveserver = 0
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect(self.host, self.port)
        self.file = self.sock.makefile('rb')
        self.welcome = self.getresp()

    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 `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.send(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 == '4':
            raise error_temp, resp
        if c == '5':
            raise error_perm, resp
        if c not in '123':
            raise error_proto, resp
        return resp

    def voidresp(self):
        """Expect a response beginning with '2'."""
        resp = self.getresp()
        if resp[0] <> '2':
            raise error_reply, 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.send(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)
        self.voidresp()

    def sendport(self, host, port):
        '''Send a PORT command with the current host and the given port number.'''
        hbytes = string.splitfields(host, '.')
        pbytes = [`port/256`, `port%256`]
        bytes = hbytes + pbytes
        cmd = 'PORT ' + string.joinfields(bytes, ',')
        self.voidcmd(cmd)

    def makeport(self):
        '''Create a new socket and send a PORT command for it.'''
        global nextport
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.bind(('', 0))
        sock.listen(1)
        dummyhost, port = sock.getsockname() # Get proper port
        host, dummyport = self.sock.getsockname() # Get proper host
        resp = self.sendport(host, port)
        return sock

    def transfercmd(self, cmd):
        '''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'''
        if self.passiveserver:
            host, port = parse227(self.sendcmd('PASV'))
            conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            conn.connect(host, port)
            resp = self.sendcmd(cmd)
            if resp[0] <> '1':
                raise error_reply, resp
        else:
            sock = self.makeport()
            resp = self.sendcmd(cmd)
            if resp[0] <> '1':
                raise error_reply, resp
            conn, sockaddr = sock.accept()
        return conn

    def login(self, user = '', passwd = '', acct = ''):
        '''Login, default anonymous.'''
        if not user: user = 'anonymous'
        if user == 'anonymous' and passwd in ('', '-'):
            thishost = socket.gethostname()
            # Make sure it is fully qualified
            if not '.' in thishost:
                thisaddr = socket.gethostbyname(thishost)
                firstname, names, unused = \
                       socket.gethostbyaddr(thisaddr)
                names.insert(0, firstname)
                for name in names:
                    if '.' in name:
                        thishost = name
                        break
            try:
                if os.environ.has_key('LOGNAME'):
                    realuser = os.environ['LOGNAME']
                elif os.environ.has_key('USER'):
                    realuser = os.environ['USER']
                else:
                    realuser = 'anonymous'
            except AttributeError:
                # Not all systems have os.environ....
                realuser = 'anonymous'
            passwd = passwd + realuser + '@' + thishost
        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

    def retrbinary(self, cmd, callback, blocksize):
        '''Retrieve data in binary mode.
        The argument is a RETR command.
        The callback function is called for each block.
        This creates a new port for you'''
        self.voidcmd('TYPE I')
        conn = self.transfercmd(cmd)
        while 1:
            data = conn.recv(blocksize)
            if not data:
                break
            callback(data)
        conn.close()
        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_lines is the default callback.'''
        if not callback: 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*', `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()
        self.voidresp()

    def storbinary(self, cmd, fp, blocksize):
        '''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.send(buf)
        conn.close()
        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.send(buf)
        conn.close()
        self.voidresp()

    def acct(self, password):
        '''Send new account name.'''
        cmd = 'ACCT ' + password
        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
        self.voidcmd('RNTO ' + toname)

        def delete(self, filename):
        '''Delete a file.'''
                resp = self.sendcmd('DELE ' + filename)
                if resp[:3] == '250':
                        return
                elif resp[:1] == '5':
                        raise error_perm, resp
                else:
                        raise error_reply, resp

    def cwd(self, dirname):
        '''Change to a directory.'''
        if dirname == '..':
            try:
                self.voidcmd('CDUP')
                return
            except error_perm, msg:
                if msg[:3] != '500':
                    raise error_perm, msg
        cmd = 'CWD ' + dirname
        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':
            return string.atoi(string.strip(resp[3:]))

    def mkd(self, dirname):
        '''Make a directory, return its full pathname.'''
        resp = self.sendcmd('MKD ' + dirname)
        return parse257(resp)

    def pwd(self):
        '''Return current working directory.'''
        resp = self.sendcmd('PWD')
        return parse257(resp)

    def quit(self):
        '''Quit, and close the connection.'''
        self.voidcmd('QUIT')
        self.close()

    def close(self):
        '''Close the connection without assuming anything about it.'''
        self.file.close()
        self.sock.close()
        del self.file, self.sock


def parse227(resp):
    '''Parse the '227' response for a PASV request.
    Raises error_proto if it does not contain '(h1,h2,h3,h4,p1,p2)'
    Return ('host.addr.as.numbers', port#) tuple.'''

    if resp[:3] <> '227':
        raise error_reply, resp
    left = string.find(resp, '(')
    if left < 0: raise error_proto, resp
    right = string.find(resp, ')', left + 1)
    if right < 0:
        raise error_proto, resp    # should contain '(h1,h2,h3,h4,p1,p2)'
    numbers = string.split(resp[left+1:right], ',')
    if len(numbers) <> 6:
        raise error_proto, resp
    host = string.join(numbers[:4], '.')
    port = (string.atoi(numbers[4]) << 8) + string.atoi(numbers[5])
    return host, port
# end parse227


def parse257(resp):
    '''Parse the '257' response for a MKD or RMD request.
    This is a response to a MKD or RMD request: a directory name.
    Returns the directoryname in the 257 reply.'''

    if resp[:3] <> '257':
        raise error_reply, resp
    if resp[3:5] <> ' "':
        return '' # Not compliant to RFC 959, but UNIX ftpd does this
    dirname = ''
    i = 5
    n = len(resp)
    while i < n:
        c = resp[i]
        i = i+1
        if c == '"':
            if i >= n or resp[i] <> '"':
                break
            i = i+1
        dirname = dirname + c
    return dirname

def print_line(line):
    '''Default retrlines callback to print a line.'''
    print line

def ftpcp(source, sourcename, target, targetname = '', type = 'I'):
    '''Copy file from one FTP-instance to another.'''
    if not targetname: targetname = sourcename
    type = 'TYPE ' + type
    source.voidcmd(type)
    target.voidcmd(type)
    sourcehost, sourceport = parse227(source.sendcmd('PASV'))
    target.sendport(sourcehost, sourceport)
    # RFC 959: the user must "listen" [...] BEFORE sending the
    # transfer request.
    # So: STOR before RETR, because here the target is a "user".
    treply = target.sendcmd('STOR ' + targetname)
    if treply[:3] not in ('125', '150'): raise error_proto    # RFC 959
    sreply = source.sendcmd('RETR ' + sourcename)
    if sreply[:3] not in ('125', '150'): raise error_proto    # RFC 959
    source.voidresp()
    target.voidresp()

def test():
    '''Test program.
    Usage: ftp [-d] host [-l[dir]] [-d[dir]] [-p] [file] ...'''

    debugging = 0
    while sys.argv[1] == '-d':
        debugging = debugging+1
        del sys.argv[1]
    host = sys.argv[1]
    ftp = FTP(host)
    ftp.set_debuglevel(debugging)
    ftp.login()
    for file in sys.argv[2:]:
        if file[:2] == '-l':
            ftp.dir(file[2:])
        elif file[:2] == '-d':
            cmd = 'CWD'
            if file[2:]: cmd = cmd + ' ' + file[2:]
            resp = ftp.sendcmd(cmd)
        elif file == '-p':
            ftp.set_pasv(not ftp.passiveserver)
        else:
            ftp.retrbinary('RETR ' + file, \
                       sys.stdout.write, 1024)
    ftp.quit()


if __name__ == '__main__':
    test()