传说中只用了十五行Python语句的P2P客户端/服务端 [转]
#zz from http://www.exonsoft.com/~kochin/TinyP2P/tinyp2p.html# tinyp2p.py 1.0 (documentation at http://freedom-to-tinker.com/tinyp2p.html)# (C) 2004, E.W. Felten# license: http://creativecommons.org/licenses/by-nc-sa/2.0 # Annotated by Kochin Chang, Jan. 2005 # Usage:# Server - python tinyp2p.py password server hostnameportnum # Client - python tinyp2p.py password client serverurl pattern# ar ar arar ar ar import sys, os, SimpleXMLRPCServer, xmlrpclib, re, hmac # Import libraries used in the program.# sys : system variables and functions.# os : portable OS dependent functionalities.# SimpleXMLRPCServer : basic XML-RPC server framework.# xmlrpclib : XML-RPC client support.# re : regular expression support.# hmac : RFC 2104 Keyed-Hashing Message Authentication. ar,pw,res = (sys.argv,lambda u:hmac.new(sys.argv,u).hexdigest(),re.search)# A multiple assignment.# ar <- sys.argv : the argument list.# pw <- lambda u:hmac.new(sys.argv,u).hexdigest() :# a function makes an HMAC digest from a URL.# INPUT: a string, u, which is a URL here.# OUTPUT: a hexdecimal HMAC digest.# DESCRIPTION:# 1. Creates a HMAC object from the URL using network's password,# sys.argv, as the key.# 2. Returns a hexdecimal digest of the HMAC object.# res <- re.search : alias for the regular expression search function. pxy,xs = (xmlrpclib.ServerProxy,SimpleXMLRPCServer.SimpleXMLRPCServer)# A multiple assignment.# pxy <- xmlrpclib.ServerProxy : alias for the ServerProxy class.# xs <- SimpleXMLRPCServer.SimpleXMLRPCServer : alias for the SimpleXMLRPCServer class. def ls(p=""):return filter(lambda n:(p=="")or res(p,n),os.listdir(os.getcwd()))# a function lists directory entries.# INPUT: a string, p, which is a regular expression pattern.# OUTPUT: a list of directory entries matched the pattern.# DESCRIPTION:# 1. Creates a function using lambda expression that takes a pathname as its# parameter. The function returns true if the pattern is empty or the# pathname matches the pattern.# 2. Finds out what is the current working directory.# 3. Retrieves a list of directory entries of current working directory.# 4. Filters the list using the lambda function defined. if ar!="client":# Running in server mode... myU,prs,srv = ("http://"+ar+":"+ar, ar,lambda x:x.serve_forever()) # A multiple assignment. # myU <- "http://"+ar+":"+ar : server's own URL. # prs <- ar : URL's of other servers in the network. # srv <- lambda x:x.serve_forever() : # a function to start a SimpleXMLRPCServer. # INPUT: a SimpleXMLRPCServer object, x. # OUTPUT: (none) # DESCRIPTION: # Calls the server's serve_forever() method to start handling request. def pr(x=[]): return ([(y in prs) or prs.append(y) for y in x] or 1) and prs # a function returns the server list. # INPUT: a list, x, of servers' URLs to be added to the server list. # OUTPUT: the updated server list. # DESCRIPTION: # 1. For each URL in x, checks whether it's already in the server list. # If it's not in the list, appends in onto the list. # 2. Returns the updated server list. def c(n): return ((lambda f: (f.read(), f.close()))(file(n))) # a function returns content of the specified file. # INPUT: a string, n, which is a filename. # OUTPUT: the content of the file in a string. # DESCRIPTION: # 1. Creates a function using lambda expression that takes a file object, f, # as its parameter. The function reads the content of the file, then # closes it. The results of the read and close are put into a tuple, and # the tuple is returned. # 2. Creates a file object with the filename. Passes it to the lambda # function. # 3. Retrieves and returns the first item returned from the lambda function. f=lambda p,n,a:(p==pw(myU))and(((n==0)and pr(a))or((n==1)and )or c(a)) # a request handling function, depending on the mode, returns server list, # directory entries, or content of a file. # INPUT: a string, p, which is a hexdecimal HMAC digest. # a mode number, n. # if n is 0, a is a list of servers to be added to server list. # if n is 1, a is a pattern string. # if n is anything else, a is a filename. # OUTPUT: if n is 0, returns the server list. # if n is 1, returns directory entries match the pattern. # if n is anything else, returns content of the file. # DESCRIPTION: # 1. Verifies the password by comparing the HMAC digest received and the # one created itself. Continues only when they match. # 2. If n is 0, calls pr() to add list, a, and returns the result. # If n is 1, calls ls() to list entries match pattern a, and returns # the result enclosed in a list. # If n is any other value, retreives and return content of the file # with filename specified in a. def aug(u): return ((u==myU) and pr()) or pr(pxy(u).f(pw(u),0,pr())) # a function augments the network. # INPUT: a string, u, which is a URL. # OUTPUT: a list of URL's of servers in the network. # DESCRIPTION: # 1. If the URL, u, equals to my own URL, just returns the server list. # 2. Otherwise, creates a ServerProxy object for server u. Then calls its # request handling function f with a HMAC digest, mode 0, and server # list with myself added. # 3. Calls pr() with the result returned from server u to add them to my # own list. # 4. Returns the new list. pr() and )] # 1. Checks the server list is not empty. # 2. Takes the first server on the list. Asks that server to augment its # server list with my URL. # 3. For each server on the returned list, asks it to add this server to its # list. (lambda sv:sv.register_function(f,"f") or srv(sv))(xs((ar,int(ar)))) # Starts request processing. # 1. Defines a function with lambda expression that takes a SimpleXMLRPCServer # object, registers request handling function, f, and starts the server. # 2. Creates a SimpleXMLRPCServer object using hostname (ar) and portnum # (ar). Then feeds the object to the lambda function. # Running in client mode...for url in pxy(ar).f(pw(ar),0,[]):# 1. Create a ServerProxy object using the serverurl (ar).# 2. Calls the remote server and retrieves a server list.# 3. For each URL on the list, do the following: for fn in filter(lambda n:not n in ls(), (pxy(url).f(pw(url),1,ar))): # 1. Create a ServerProxy object using the URL. # 2. Calls the remote server to return a list of filenames matching the # pattern (ar). # 3. For each filename doesn't exist locally, do the following: (lambda fi:fi.write(pxy(url).f(pw(url),2,fn)) or fi.close())(file(fn,"wc")) # 1. Define a lambda function that takes a file object, calls remote server # for the file content, then closes the file. # 2. Create a file object in write and binary mode with the filename. (I # think the mode "wc" should be "wb".) # 3. Passes the file object to the lambda function.
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