Mac-Source 1994 July/Mac-Source_July_1994.iso/Other Langs/python/Lib/ftplib.py

Python Source | 1994-04-01 | 12.3 KB | 453 lines | [TEXT/R*ch]

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

# Changes and improvements suggested by Steve Majewski


# Example:
#
# >>> from ftplib import FTP
# >>> ftp = FTP('ftp.cwi.nl') # connect to host, default port
# >>> ftp.login() # default, i.e.: user anonymous, passwd user@hostname
# >>> def handle_one_line(line): # callback for ftp.retrlines
# ...     print line
# ...
# >>> ftp.retrlines('LIST', handle_one_line) # list directory contents
# total 43
# d--x--x--x   2 root     root         512 Jul  1 16:50 bin
# d--x--x--x   2 root     root         512 Sep 16  1991 etc
# drwxr-xr-x   2 root     ftp        10752 Sep 16  1991 lost+found
# drwxr-srwt  15 root     ftp        10240 Nov  5 20:43 pub
# >>> ftp.quit()
#
# To download a file, use ftp.retrlines('RETR ' + filename, handle_one_line),
# or ftp.retrbinary() with slightly different arguments.
# To upload a file, use ftp.storlines() or ftp.storbinary(), which have
# an open file as argument.
# The download/upload functions first issue appropriate TYPE and PORT
# commands.


import os
import sys
import socket
import string


# 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)


# Line terminators (we always output CRLF, but accept any of CRLF, CR, LF)
CRLF = '\r\n'


# Next port to be used by makeport(), with PORT_OFFSET added
# (This is now only used when the python interpreter doesn't support
# the getsockname() method yet)
nextport = 0
PORT_OFFSET = 40000
PORT_CYCLE = 1000


# The class itself
class FTP:

    # New 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, *args):
        # 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 args:
            self.connect(args[0])
            if args[1:]:
                apply(self.login, args[1:])

    # Connect to host.  Arguments:
    # - host: hostname to connect to (default previous host)
    # - port: port to connect to (default previous port)
    def connect(self, *args):
        if args: self.host = args[0]
        if args[1:]: self.port = args[1]
        if args[2:]: raise TypeError, 'too many args'
        self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.sock.connect(self.host, self.port)
        self.file = self.sock.makefile('r')
        self.welcome = self.getresp()

    # Get the welcome message from the server
    # (this is read and squirreled away by connect())
    def getwelcome(self):
        if self.debugging: print '*welcome*', `self.welcome`
        return self.welcome

    # Set the debugging level.  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
    def set_debuglevel(self, level):
        self.debugging = level
    debug = set_debuglevel

    # Internal: send one line to the server, appending CRLF
    def putline(self, line):
        line = line + CRLF
        if self.debugging > 1: print '*put*', `line`
        self.sock.send(line)

    # Internal: send one command to the server (through putline())
    def putcmd(self, line):
        if self.debugging: print '*cmd*', `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*', `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*', `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

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

    # 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.
    def abort(self):
        line = 'ABOR' + CRLF
        if self.debugging > 1: print '*put urgent*', `line`
        self.sock.send(line, MSG_OOB)
        resp = self.getmultiline()
        if resp[:3] not in ('426', '226'):
            raise error_proto, resp

    # Send a command and return the response
    def sendcmd(self, cmd):
        self.putcmd(cmd)
        return self.getresp()

    # Send a command and expect a response beginning with '2'
    def voidcmd(self, cmd):
        self.putcmd(cmd)
        self.voidresp()

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

    # Create a new socket and send a PORT command for it
    def makeport(self):
        global nextport
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        try:
            getsockname = sock.getsockname
        except AttributeError:
            if self.debugging > 1:
                print '*** getsockname not supported',
                print '-- using manual port assignment ***'
            port = nextport + PORT_OFFSET
            nextport = (nextport + 1) % PORT_CYCLE
            sock.bind('', port)
            getsockname = None
        sock.listen(0) # Assigns the port if not explicitly bound
        if getsockname:
            host, port = getsockname()
        resp = self.sendport(port)
        return sock

    # Send a port command and a transfer command, accept the connection
    # and return the socket for the connection
    def transfercmd(self, cmd):
        sock = self.makeport()
        resp = self.sendcmd(cmd)
        if resp[0] <> '1':
            raise error_reply, resp
        conn, sockaddr = sock.accept()
        return conn

    # Login, default anonymous
    def login(self, *args):
        user = passwd = acct = ''
        n = len(args)
        if n > 3: raise TypeError, 'too many arguments'
        if n > 0: user = args[0]
        if n > 1: passwd = args[1]
        if n > 2: acct = args[2]
        if not user: user = 'anonymous'
        if user == 'anonymous' and passwd in ('', '-'):
            thishost = socket.gethostname()
            if os.environ.has_key('LOGNAME'):
                realuser = os.environ['LOGNAME']
            elif os.environ.has_key('USER'):
                realuser = os.environ['USER']
            else:
                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

    # 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
    def retrbinary(self, cmd, callback, blocksize):
        self.voidcmd('TYPE I')
        conn = self.transfercmd(cmd)
        while 1:
            data = conn.recv(blocksize)
            if not data:
                break
            callback(data)
        conn.close()
        self.voidresp()

    # Retrieve data in line mode.
    # The argument is a RETR or LIST command.
    # The callback function is called for each line, with trailing
    # CRLF stripped.  This creates a new port for you.
    # print_lines is the default callback
    def retrlines(self, cmd, *args):
        callback = None
        if args:
            callback = args[0]
            if args[1:]: raise TypeError, 'too many args'
        if not callback: callback = print_line
        resp = self.sendcmd('TYPE A')
        conn = self.transfercmd(cmd)
        fp = conn.makefile('r')
        while 1:
            line = fp.readline()
            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()

    # Store a file in binary mode
    def storbinary(self, cmd, fp, blocksize):
        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()

    # Store a file in line mode
    def storlines(self, cmd, fp):
        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()

    # Return a list of files in a given directory (default the current)
    def nlst(self, *args):
        cmd = 'NLST'
        for arg in args:
            cmd = cmd + (' ' + arg)
        files = []
        self.retrlines(cmd, files.append)
        return files

    # 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.)
    def dir(self, *args):
        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)

    # Rename a file
    def rename(self, fromname, toname):
        resp = self.sendcmd('RNFR ' + fromname)
        if resp[0] <> '3':
            raise error_reply, resp
        self.voidcmd('RNTO ' + toname)

    # Change to a directory
    def cwd(self, dirname):
        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)

    # Retrieve the size of a file
    def size(self, filename):
        resp = self.sendcmd('SIZE ' + filename)
        if resp[:3] == '213':
            return string.atoi(string.strip(resp[3:]))

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

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

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

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


# Parse a response type 257
def parse257(resp):
    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

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


# Test program.
# Usage: ftp [-d] host [-l[dir]] [-d[dir]] [file] ...
def test():
    import marshal
    global nextport
    try:
        nextport = marshal.load(open('.@nextport', 'r'))
    except IOError:
        pass
    try:
        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)
            else:
                ftp.retrbinary('RETR ' + file, \
                           sys.stdout.write, 1024)
        ftp.quit()
    finally:
        marshal.dump(nextport, open('.@nextport', 'w'))