Python之路,Day8 - Socket编程进阶
本节内容:
???Socket语法及相关socket概念socket本质上就是在2台网络互通的电脑之间,架设一个通道,两台电脑通过这个通道来实现数据的互相传递。 我们知道网络 通信 都 是基于 ip+port 方能定位到目标的具体机器上的具体服务,操作系统有0-65535个端口,每个端口都可以独立对外提供服务,如果 把一个公司比做一台电脑 ,那公司的总机号码就相当于ip地址, 每个员工的分机号就相当于端口, 你想找公司某个人,必须 先打电话到总机,然后再转分机 。 建立一个socket必须至少有2端, 一个服务端,一个客户端, 服务端被动等待并接收请求,客户端主动发起请求, 连接建立之后,双方可以互发数据。? A?network socket?is an endpoint of a connection across a?. Today,most communication between computers is based on the?; therefore most network sockets are?Internet sockets. More precisely,a socket is a??(abstract reference) that a local program can pass to the networking??(API) to use the connection,for example "send this data on this socket". Sockets are internally often simply?,which identify which connection to use. For example,to send "Hello,world!" via??to port 80 of the host with address 1.2.3.4,one might get a socket,connect it to the remote host,send the string,then close the socket: A?socket API?is an??(API),usually provided by the?,that allows application programs to control and use network sockets. Internet socket APIs are usually based on the??standard. In the Berkeley sockets standard,sockets are a form of??(a?file?handle),due to the??that "everything is a file",and the analogies between sockets and files: you can read,write,open,and close both. In practice the differences mean the analogy is strained,and one instead use different interfaces (send and receive) on a socket. In?,each end will generally have its own socket,but these may use different APIs: they are abstracted by the network protocol. A?socket address?is the combination of an??and a?,much like one end of a telephone connection is the combination of a??and a particular?. Sockets need not have an address (for example for only sending data),but if a program?binds?a socket to an address,the socket can be used to receive data sent to that address. Based on this address,internet sockets deliver incoming data packets to the appropriate application??or?. Socket Families(地址簇)
Socket TypesThese constants represent the socket types,used for the second argument to?. More constants may be available depending on the system. (Only??and??appear to be generally useful.)
Socket 方法
family=AF_INET,?type=SOCK_STREAM,?proto=0,?fileno=None
Create a new socket using the given address family,socket type and protocol number. The address family should be??(the default),?,?,??or?. The socket type should be?(the default),?,??or perhaps one of the other?
Build a pair of connected socket objects using the given address family,socket type,and protocol number. Address family,and protocol number are as for the??function above. The default family is??if defined on the platform; otherwise,the default is?.
Connect to a TCP service listening on the Internet?address?(a 2-tuple? Passing the optional?timeout?parameter will set the timeout on the socket instance before attempting to connect. If no?timeout?is supplied,the global default timeout setting returned by??is used. If supplied,?source_address?must be a 2-tuple?
sk.bind(address) s.bind(address) 将套接字绑定到地址。address地址的格式取决于地址族。在AF_INET下,以元组(host,port)的形式表示地址。 sk.listen(backlog) 开始监听传入连接。backlog指定在拒绝连接之前,可以挂起的最大连接数量。 ? ? ? backlog等于5,表示内核已经接到了连接请求,但服务器还没有调用accept进行处理的连接个数最大为5? ? ? 这个值不能无限大,因为要在内核中维护连接队列 sk.setblocking(bool) 是否阻塞(默认True),如果设置False,那么accept和recv时一旦无数据,则报错。 sk.accept() 接受连接并返回(conn,address),其中conn是新的套接字对象,可以用来接收和发送数据。address是连接客户端的地址。 接收TCP 客户的连接(阻塞式)等待连接的到来 sk.connect(address) 连接到address处的套接字。一般,address的格式为元组(hostname,port),如果连接出错,返回socket.error错误。 sk.connect_ex(address) 同上,只不过会有返回值,连接成功时返回 0 ,连接失败时候返回编码,例如:10061 sk.close() 关闭套接字 sk.recv(bufsize[,flag]) 接受套接字的数据。数据以字符串形式返回,bufsize指定最多可以接收的数量。flag提供有关消息的其他信息,通常可以忽略。 sk.recvfrom(bufsize[.flag]) 与recv()类似,但返回值是(data,address)。其中data是包含接收数据的字符串,address是发送数据的套接字地址。 sk.send(string[,flag]) 将string中的数据发送到连接的套接字。返回值是要发送的字节数量,该数量可能小于string的字节大小。即:可能未将指定内容全部发送。 sk.sendall(string[,flag]) 将string中的数据发送到连接的套接字,但在返回之前会尝试发送所有数据。成功返回None,失败则抛出异常。 ? ? ? 内部通过递归调用send,将所有内容发送出去。 sk.sendto(string[,flag],address) 将数据发送到套接字,address是形式为(ipaddr,port)的元组,指定远程地址。返回值是发送的字节数。该函数主要用于UDP协议。 sk.settimeout(timeout) 设置套接字操作的超时期,timeout是一个浮点数,单位是秒。值为None表示没有超时期。一般,超时期应该在刚创建套接字时设置,因为它们可能用于连接的操作(如 client 连接最多等待5s ) sk.getpeername() 返回连接套接字的远程地址。返回值通常是元组(ipaddr,port)。 sk.getsockname() 返回套接字自己的地址。通常是一个元组(ipaddr,port) sk.fileno() 套接字的文件描述符
The??module simplifies the task of writing network servers. There are four basic concrete server classes:
,?RequestHandlerClass,?bind_and_activate=True
,?bind_and_activate=True
,?bind_and_activate=True
These four classes process requests?; each request must be completed before the next request can be started. This isn’t suitable if each request takes a long time to complete,because it requires a lot of computation,or because it returns a lot of data which the client is slow to process. The solution is to create a separate process or thread to handle each request; the??and??mix-in classes can be used to support asynchronous behaviour. There are five classes in an inheritance diagram,four of which represent synchronous servers of four types: | |
Note that??derives from?,not from??— the only difference between an IP and a Unix stream server is the address family,which is simply repeated in both Unix server classes.
. Setting the various attributes also changes the behavior of the underlying server mechanism.
?raises an exception,this function will not be called.
?Exampleserver side class MyTCPHandler(socketserver.BaseRequestHandler):
""" The request handler class for our server.
if name == "main":
client side HOST,9999
data = " ".join(sys.argv[1:]) Create a socket (SOCK_STREAM means a TCP socket)sock = socket.socket(socket.AF_INET,socket.SOCK_STREAM) try: Connect to server and send data
finally: print("Sent: {}".format(data)) 上面这个例子你会发现,依然不能实现多并发,哈哈,在server端做一下更改就可以了把
<div class="cnblogs_Highlighter">
线程与进程http://www.cnblogs.com/alex3714/articles/5230609.html?
主机管理之paramiko模块学习?http://www.cnblogs.com/wupeiqi/articles/5095821.html? 作业1:用socketserver继续完善FTP作业 需求: (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |