400多行Python代码实现了一个FTP服务器

Python版本
实现了比之前的xxftp更多更完善的功能
1、继续支持多用户
2、继续支持虚拟目录
3、增加支持用户根目录以及映射虚拟目录的权限设置
4、增加支持限制用户根目录或者虚拟目录的空间大小

xxftp的特点
1、开源、跨平台
2、简单、易用
3、不需要数据库
4、可扩展性超强
5、你可以免费使用xxftp假设自己的私人FTP服务器

测试地址
ftp://xiaoxia.org
匿名帐号可以使用！
匿名根目录只读，映射了一个虚拟目录，可以上传文件但不允许更改！

使用方法
跟之前用C语言写的xxftp使用方法一样：

1. Create a root directory to hold the user directories.
Configure it in config.xml.
2. Create user directories under the root directory.
If you want to specify a password, create a directory named ".xxftp",
under which create a text file named "password" containing the MD5
code of the password.
3. If you want to specify the welcome and goodbye message, write it in
xxftp.welcome and xxftp.goodbye under the root directory.
4. Configure config.xml.

The structure of your FTP server root may be like:

-/root
-xxftp.welcome
-xxftp.goodbye

-user1
-.xxftp
-password
-...
-user2
-.xxftp
-password
-...
-anonymous源代码

import socket, threading, os, sys, time 
import hashlib, platform, stat 
listen_ip = "localhost" 
listen_port = 21 
conn_list = [] 
root_dir = "./home" 
max_connections = 500 
conn_timeout = 120 
class FtpConnection(threading.Thread): 
def __init__(self, fd): 
threading.Thread.__init__(self) 
self.fd = fd 
self.running = True 
self.setDaemon(True) 
self.alive_time = time.time() 
self.option_utf8 = False 
self.identified = False 
self.option_pasv = True 
self.username = "" 
def process(self, cmd, arg): 
cmd = cmd.upper(); 
if self.option_utf8: 
arg = unicode(arg, "utf8").encode(sys.getfilesystemencoding()) 
print "<<", cmd, arg, self.fd 
# Ftp Command 
if cmd == "BYE" or cmd == "QUIT": 
if os.path.exists(root_dir + "/xxftp.goodbye"): 
self.message(221, open(root_dir + "/xxftp.goodbye").read()) 
else: 
self.message(221, "Bye!") 
self.running = False 
return 
elif cmd == "USER": 
# Set Anonymous User 
if arg == "": arg = "anonymous" 
for c in arg: 
if not c.isalpha() and not c.isdigit() and c!="_": 
self.message(530, "Incorrect username.") 
return 
self.username = arg 
self.home_dir = root_dir + "/" + self.username 
self.curr_dir = "/" 
self.curr_dir, self.full_path, permission, self.vdir_list, \ 
limit_size, is_virtual = self.parse_path("/") 
if not os.path.isdir(self.home_dir): 
self.message(530, "User " + self.username + " not exists.") 
return 
self.pass_path = self.home_dir + "/.xxftp/password" 
if os.path.isfile(self.pass_path): 
self.message(331, "Password required for " + self.username) 
else: 
self.message(230, "Identified!") 
self.identified = True 
return 
elif cmd == "PASS": 
if open(self.pass_path).read() == hashlib.md5(arg).hexdigest(): 
self.message(230, "Identified!") 
self.identified = True 
else: 
self.message(530, "Not identified!") 
self.identified = False 
return 
elif not self.identified: 
self.message(530, "Please login with USER and PASS.") 
return 
self.alive_time = time.time() 
finish = True 
if cmd == "NOOP": 
self.message(200, "ok") 
elif cmd == "TYPE": 
self.message(200, "ok") 
elif cmd == "SYST": 
self.message(200, "UNIX") 
elif cmd == "EPSV" or cmd == "PASV": 
self.option_pasv = True 
try: 
self.data_fd = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
self.data_fd.bind((listen_ip, 0)) 
self.data_fd.listen(1) 
ip, port = self.data_fd.getsockname() 
if cmd == "EPSV": 
self.message(229, "Entering Extended Passive Mode (|||" + str(port) + "|)") 
else: 
ipnum = socket.inet_aton(ip) 
self.message(227, "Entering Passive Mode (%s,%u,%u)." % 
(",".join(ip.split(".")), (port>>8&0xff), (port&0xff))) 
except: 
self.message(500, "failed to create data socket.") 
elif cmd == "EPRT": 
self.message(500, "implement EPRT later...") 
elif cmd == "PORT": 
self.option_pasv = False 
self.data_fd = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
s = arg.split(",") 
self.data_ip = ".".join(s[:4]) 
self.data_port = int(s[4])*256 + int(s[5]) 
self.message(200, "ok") 
elif cmd == "PWD" or cmd == "XPWD": 
if self.curr_dir == "": self.curr_dir = "/" 
self.message(257, '"' + self.curr_dir + '"') 
elif cmd == "LIST" or cmd == "NLST": 
if arg != "" and arg[0] == "-": arg = "" # omit parameters 
remote, local, perm, vdir_list, limit_size, is_virtual = self.parse_path(arg) 
if not os.path.exists(local): 
self.message(550, "failed.") 
return 
if not self.establish(): return 
self.message(150, "ok") 
for v in vdir_list: 
f = v[0] 
if self.option_utf8: 
f = unicode(f, sys.getfilesystemencoding()).encode("utf8") 
if cmd == "NLST": 
info = f + "\r\n" 
else: 
info = "d%s%s------- %04u %8s %8s %8lu %s %s\r\n" % ( 
"r" if "read" in perm else "-", 
"w" if "write" in perm else "-", 
1, "0", "0", 0, 
time.strftime("%b %d %Y", time.localtime(time.time())), 
f) 
self.data_fd.send(info) 
for f in os.listdir(local): 
if f[0] == ".": continue 
path = local + "/" + f 
if self.option_utf8: 
f = unicode(f, sys.getfilesystemencoding()).encode("utf8") 
if cmd == "NLST": 
info = f + "\r\n" 
else: 
st = os.stat(path) 
info = "%s%s%s------- %04u %8s %8s %8lu %s %s\r\n" % ( 
"-" if os.path.isfile(path) else "d", 
"r" if "read" in perm else "-", 
"w" if "write" in perm else "-", 
1, "0", "0", st[stat.ST_SIZE], 
time.strftime("%b %d %Y", time.localtime(st[stat.ST_MTIME])), 
f) 
self.data_fd.send(info) 
self.message(226, "Limit size: " + str(limit_size)) 
self.data_fd.close() 
self.data_fd = 0 
elif cmd == "REST": 
self.file_pos = int(arg) 
self.message(250, "ok") 
elif cmd == "FEAT": 
features = "211-Features:\r\nSITES\r\nEPRT\r\nEPSV\r\nMDTM\r\nPASV\r\n"\ 
"REST STREAM\r\nSIZE\r\nUTF8\r\n211 End\r\n" 
self.fd.send(features) 
elif cmd == "OPTS": 
arg = arg.upper() 
if arg == "UTF8 ON": 
self.option_utf8 = True 
self.message(200, "ok") 
elif arg == "UTF8 OFF": 
self.option_utf8 = False 
self.message(200, "ok") 
else: 
self.message(500, "unrecognized option") 
elif cmd == "CDUP": 
finish = False 
arg = ".." 
else: 
finish = False 
if finish: return 
# Parse argument ( It's a path ) 
if arg == "": 
self.message(500, "where's my argument?") 
return 
remote, local, permission, vdir_list, limit_size, is_virtual = \ 
self.parse_path(arg) 
# can not do anything to virtual directory 
if is_virtual: permission = "none" 
can_read, can_write, can_modify = "read" in permission, "write" in permission, "modify" in permission 
newpath = local 
try: 
if cmd == "CWD": 
if(os.path.isdir(newpath)): 
self.curr_dir = remote 
self.full_path = newpath 
self.message(250, '"' + remote + '"') 
else: 
self.message(550, "failed") 
elif cmd == "MDTM": 
if os.path.exists(newpath): 
self.message(213, time.strftime("%Y%m%d%I%M%S", time.localtime( 
os.path.getmtime(newpath)))) 
else: 
self.message(550, "failed") 
elif cmd == "SIZE": 
self.message(231, os.path.getsize(newpath)) 
elif cmd == "XMKD" or cmd == "MKD": 
if not can_modify: 
self.message(550, "permission denied.") 
return 
os.mkdir(newpath) 
self.message(250, "ok") 
elif cmd == "RNFR": 
if not can_modify: 
self.message(550, "permission denied.") 
return 
self.temp_path = newpath 
self.message(350, "rename from " + remote) 
elif cmd == "RNTO": 
os.rename(self.temp_path, newpath) 
self.message(250, "RNTO to " + remote) 
elif cmd == "XRMD" or cmd == "RMD": 
if not can_modify: 
self.message(550, "permission denied.") 
return 
os.rmdir(newpath) 
self.message(250, "ok") 
elif cmd == "DELE": 
if not can_modify: 
self.message(550, "permission denied.") 
return 
os.remove(newpath) 
self.message(250, "ok") 
elif cmd == "RETR": 
if not os.path.isfile(newpath): 
self.message(550, "failed") 
return 
if not can_read: 
self.message(550, "permission denied.") 
return 
if not self.establish(): return 
self.message(150, "ok") 
f = open(newpath, "rb") 
while self.running: 
self.alive_time = time.time() 
data = f.read(8192) 
if len(data) == 0: break 
self.data_fd.send(data) 
f.close() 
self.data_fd.close() 
self.data_fd = 0 
self.message(226, "ok") 
elif cmd == "STOR" or cmd == "APPE": 
if not can_write: 
self.message(550, "permission denied.") 
return 
if os.path.exists(newpath) and not can_modify: 
self.message(550, "permission denied.") 
return 
# Check space size remained! 
used_size = 0 
if limit_size > 0: 
used_size = self.get_dir_size(os.path.dirname(newpath)) 
if not self.establish(): return 
self.message(150, "ok") 
f = open(newpath, ("ab" if cmd == "APPE" else "wb") ) 
while self.running: 
self.alive_time = time.time() 
data = self.data_fd.recv(8192) 
if len(data) == 0: break 
if limit_size > 0: 
used_size = used_size + len(data) 
if used_size > limit_size: break 
f.write(data) 
f.close() 
self.data_fd.close() 
self.data_fd = 0 
if limit_size > 0 and used_size > limit_size: 
self.message(550, "Exceeding user space limit: " + str(limit_size) + " bytes") 
else: 
self.message(226, "ok") 
else: 
self.message(500, cmd + " not implemented") 
except: 
self.message(550, "failed.") 
def establish(self): 
if self.data_fd == 0: 
self.message(500, "no data connection") 
return False 
if self.option_pasv: 
fd = self.data_fd.accept()[0] 
self.data_fd.close() 
self.data_fd = fd 
else: 
try: 
self.data_fd.connect((self.data_ip, self.data_port)) 
except: 
self.message(500, "failed to establish data connection") 
return False 
return True 
def read_virtual(self, path): 
vdir_list = [] 
path = path + "/.xxftp/virtual" 
if os.path.isfile(path): 
for v in open(path, "r").readlines(): 
items = v.split() 
items[1] = items[1].replace("$root", root_dir) 
vdir_list.append(items) 
return vdir_list 
def get_dir_size(self, folder): 
size = 0 
for path, dirs, files in os.walk(folder): 
for f in files: 
size += os.path.getsize(os.path.join(path, f)) 
return size 
def read_size(self, path): 
size = 0 
path = path + "/.xxftp/size" 
if os.path.isfile(path): 
size = int(open(path, "r").readline()) 
return size 
def read_permission(self, path): 
permission = "read,write,modify" 
path = path + "/.xxftp/permission" 
if os.path.isfile(path): 
permission = open(path, "r").readline() 
return permission 
def parse_path(self, path): 
if path == "": path = "." 
if path[0] != "/": 
path = self.curr_dir + "/" + path 
s = os.path.normpath(path).replace("\\", "/").split("/") 
local = self.home_dir 
# reset directory permission 
vdir_list = self.read_virtual(local) 
limit_size = self.read_size(local) 
permission = self.read_permission(local) 
remote = "" 
is_virtual = False 
for name in s: 
name = name.lstrip(".") 
if name == "": continue 
remote = remote + "/" + name 
is_virtual = False 
for v in vdir_list: 
if v[0] == name: 
permission = v[2] 
local = v[1] 
limit_size = self.read_size(local) 
is_virtual = True 
if not is_virtual: local = local + "/" + name 
vdir_list = self.read_virtual(local) 
return (remote, local, permission, vdir_list, limit_size, is_virtual) 
def run(self): 
''' Connection Process ''' 
try: 
if len(conn_list) > max_connections: 
self.message(500, "too many connections!") 
self.fd.close() 
self.running = False 
return 
# Welcome Message 
if os.path.exists(root_dir + "/xxftp.welcome"): 
self.message(220, open(root_dir + "/xxftp.welcome").read()) 
else: 
self.message(220, "xxftp(Python) www.xiaoxia.org") 
# Command Loop 
line = "" 
while self.running: 
data = self.fd.recv(4096) 
if len(data) == 0: break 
line += data 
if line[-2:] != "\r\n": continue 
line = line[:-2] 
space = line.find(" ") 
if space == -1: 
self.process(line, "") 
else: 
self.process(line[:space], line[space+1:]) 
line = "" 
except: 
print "error", sys.exc_info() 
self.running = False 
self.fd.close() 
print "connection end", self.fd, "user", self.username 
def message(self, code, s): 
''' Send Ftp Message ''' 
s = str(s).replace("\r", "") 
ss = s.split("\n") 
if len(ss) > 1: 
r = (str(code) + "-") + ("\r\n" + str(code) + "-").join(ss[:-1]) 
r += "\r\n" + str(code) + " " + ss[-1] + "\r\n" 
else: 
r = str(code) + " " + ss[0] + "\r\n" 
if self.option_utf8: 
r = unicode(r, sys.getfilesystemencoding()).encode("utf8") 
self.fd.send(r) 
def server_listen(): 
global conn_list 
listen_fd = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
listen_fd.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) 
listen_fd.bind((listen_ip, listen_port)) 
listen_fd.listen(1024) 
conn_lock = threading.Lock() 
print "ftpd is listening on ", listen_ip + ":" + str(listen_port) 
while True: 
conn_fd, remote_addr = listen_fd.accept() 
print "connection from ", remote_addr, "conn_list", len(conn_list) 
conn = FtpConnection(conn_fd) 
conn.start() 
conn_lock.acquire() 
conn_list.append(conn) 
# check timeout 
try: 
curr_time = time.time() 
for conn in conn_list: 
if int(curr_time - conn.alive_time) > conn_timeout: 
if conn.running == True: 
conn.fd.shutdown(socket.SHUT_RDWR) 
conn.running = False 
conn_list = [conn for conn in conn_list if conn.running] 
except: 
print sys.exc_info() 
conn_lock.release() 
def main(): 
server_listen() 
if __name__ == "__main__": 
main()