网络编程之socket

import socket

#创建socket对象
sock_ser = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

#绑定ip和端口
sock_ser.bind((‘127.0.0.1‘,8000))

#监听ip和端口
sock_ser.listen(5)

#不断循环连接，等待多个客户端连接
while True:
    conn, addr = sock_ser.accept()
    #不断循环通信，与客户端连续交互
    while True:
        msg = conn.recv(1024) #收消息
        if msg:
            print(‘客户端发来的消息是：‘, msg.decode()) #客户端发来的消息是： b‘\xe4\xbd\xa0\xe5\xa5\xbd‘
            # 发送消息
            conn.send(msg.upper())
        else:
            break #如果没有消息发送过来就退出循环
#关闭连接
    conn.close()
#关闭套接字socket
sock_ser.close()

# import socket
#
# #创建socket对象
# sock_cli = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
#
# #连接服务端监听的ip和端口
# sock_cli.connect(("127.0.0.1",8000))
#
# #发送消息
# sock_cli.send(bytes("你好",encoding="utf-8"))
#
# #接收消息
# data = sock_cli.recv(1024)
# print(‘服务端发来的消息‘,data) #服务端发来的消息 b‘\xe4\xbd\xa0\xe5\xa5\xbd‘
#
# #关闭套接字socket对象
# sock_cli.close()

import socket

#创建socket对象
sock_cli = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

#连接服务端监听的ip和端口
sock_cli.connect(("127.0.0.1",8000))

while True:
    #发送消息
    msg = input(‘>>:‘)
    if msg:
        sock_cli.send(msg.encode()) #将字符串转成字节，或者sock_cli.send(bytes(msg,encoding=""utf-8))
        #接收消息
        data = sock_cli.recv(1024)
        print(‘服务端发来的消息‘,data.decode()) #服务端发来的消息 b‘\xe4\xbd\xa0\xe5\xa5\xbd‘
    else:
        break
#关闭套接字socket对象
sock_cli.close()

import socket

#创建socket对象
sock_ser = socket.socket(socket.AF_INET,socket.SOCK_STREAM)

#绑定ip和端口
sock_ser.bind((‘127.0.0.1‘,8000))

#监听ip和端口
sock_ser.listen(5)

# 不断循环连接，等待多个客户端连接
while True:
    conn, addr = sock_ser.accept()
    #不断循环通信，与客户端连续交互
    while True:
        #加入异常处理，如果有客户端断开，服务端不会报错，继续处理下一个连接的请求
        try:
            msg = conn.recv(1024) #收消息
            if msg:
                print(‘客户端发来的消息是：‘, msg.decode()) #客户端发来的消息是： b‘\xe4\xbd\xa0\xe5\xa5\xbd‘
                # 发送消息
                conn.send(msg.upper())
            else:
                break #如果没有消息发送过来就退出循环
        except Exception as e:
            break
#关闭连接
    conn.close()
#关闭套接字socket
sock_ser.close()

class ThreadingTCPServer(ThreadingMixIn, TCPServer): pass

class TCPServer(BaseServer):

    """Base class for various socket-based server classes.

    Defaults to synchronous IP stream (i.e., TCP).

    Methods for the caller:

    - __init__(server_address, RequestHandlerClass, bind_and_activate=True)
    - serve_forever(poll_interval=0.5)
    - shutdown()
    - handle_request()  # if you don‘t use serve_forever()
    - fileno() -> int   # for selector

    Methods that may be overridden:

    - server_bind()
    - server_activate()
    - get_request() -> request, client_address
    - handle_timeout()
    - verify_request(request, client_address)
    - process_request(request, client_address)
    - shutdown_request(request)
    - close_request(request)
    - handle_error()

    Methods for derived classes:

    - finish_request(request, client_address)

    Class variables that may be overridden by derived classes or
    instances:

    - timeout
    - address_family
    - socket_type
    - request_queue_size (only for stream sockets)
    - allow_reuse_address

    Instance variables:

    - server_address
    - RequestHandlerClass
    - socket

    """

    address_family = socket.AF_INET

    socket_type = socket.SOCK_STREAM

    request_queue_size = 5

    allow_reuse_address = False

    def __init__(self, server_address, RequestHandlerClass, bind_and_activate=True):
        """Constructor.  May be extended, do not override."""
        BaseServer.__init__(self, server_address, RequestHandlerClass)
        self.socket = socket.socket(self.address_family,
                                    self.socket_type)
        if bind_and_activate:
            try:
                self.server_bind() #self.socket.bind(self.server_address)  绑定主机和端口
                self.server_activate() #elf.socket.listen(self.request_queue_size) 监听
            except:
                self.server_close()
                raise

    def server_bind(self):
        """Called by constructor to bind the socket.

        May be overridden.

        """
        if self.allow_reuse_address:
            self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.socket.bind(self.server_address)
        self.server_address = self.socket.getsockname()

    def server_activate(self):
        """Called by constructor to activate the server.

        May be overridden.

        """
        self.socket.listen(self.request_queue_size)

    def server_close(self):
        """Called to clean-up the server.

        May be overridden.

        """
        self.socket.close()

    def fileno(self):
        """Return socket file number.

        Interface required by selector.

        """
        return self.socket.fileno()

    def get_request(self):
        """Get the request and client address from the socket.

        May be overridden.

        """
        return self.socket.accept()

    def shutdown_request(self, request):
        """Called to shutdown and close an individual request."""
        try:
            #explicitly shutdown.  socket.close() merely releases
            #the socket and waits for GC to perform the actual close.
            request.shutdown(socket.SHUT_WR)
        except OSError:
            pass #some platforms may raise ENOTCONN here
        self.close_request(request)

    def close_request(self, request):
        """Called to clean up an individual request."""
        request.close()

class BaseServer:

    """Base class for server classes.

    Methods for the caller:

    - __init__(server_address, RequestHandlerClass)
    - serve_forever(poll_interval=0.5)
    - shutdown()
    - handle_request()  # if you do not use serve_forever()
    - fileno() -> int   # for selector

    Methods that may be overridden:

    - server_bind()
    - server_activate()
    - get_request() -> request, client_address
    - handle_timeout()
    - verify_request(request, client_address)
    - server_close()
    - process_request(request, client_address)
    - shutdown_request(request)
    - close_request(request)
    - service_actions()
    - handle_error()

    Methods for derived classes:

    - finish_request(request, client_address)

    Class variables that may be overridden by derived classes or
    instances:

    - timeout
    - address_family
    - socket_type
    - allow_reuse_address

    Instance variables:

    - RequestHandlerClass
    - socket

    """

    timeout = None

    def __init__(self, server_address, RequestHandlerClass):
        """Constructor.  May be extended, do not override."""
        self.server_address = server_address
        self.RequestHandlerClass = RequestHandlerClass
        self.__is_shut_down = threading.Event()
        self.__shutdown_request = False

    def server_activate(self):
        """Called by constructor to activate the server.

        May be overridden.

        """
        pass

    def serve_forever(self, poll_interval=0.5):
        """Handle one request at a time until shutdown.

        Polls for shutdown every poll_interval seconds. Ignores
        self.timeout. If you need to do periodic tasks, do them in
        another thread.
        """
        self.__is_shut_down.clear()
        try:
            # XXX: Consider using another file descriptor or connecting to the
            # socket to wake this up instead of polling. Polling reduces our
            # responsiveness to a shutdown request and wastes cpu at all other
            # times.
            with _ServerSelector() as selector:
                selector.register(self, selectors.EVENT_READ)

                while not self.__shutdown_request:
                    ready = selector.select(poll_interval)
                    if ready:
                        self._handle_request_noblock()

                    self.service_actions()
        finally:
            self.__shutdown_request = False
            self.__is_shut_down.set()

    def shutdown(self):
        """Stops the serve_forever loop.

        Blocks until the loop has finished. This must be called while
        serve_forever() is running in another thread, or it will
        deadlock.
        """
        self.__shutdown_request = True
        self.__is_shut_down.wait()

    def service_actions(self):
        """Called by the serve_forever() loop.

        May be overridden by a subclass / Mixin to implement any code that
        needs to be run during the loop.
        """
        pass

    # The distinction between handling, getting, processing and finishing a
    # request is fairly arbitrary.  Remember:
    #
    # - handle_request() is the top-level call.  It calls selector.select(),
    #   get_request(), verify_request() and process_request()
    # - get_request() is different for stream or datagram sockets
    # - process_request() is the place that may fork a new process or create a
    #   new thread to finish the request
    # - finish_request() instantiates the request handler class; this
    #   constructor will handle the request all by itself

    def handle_request(self):
        """Handle one request, possibly blocking.

        Respects self.timeout.
        """
        # Support people who used socket.settimeout() to escape
        # handle_request before self.timeout was available.
        timeout = self.socket.gettimeout()
        if timeout is None:
            timeout = self.timeout
        elif self.timeout is not None:
            timeout = min(timeout, self.timeout)
        if timeout is not None:
            deadline = time() + timeout

        # Wait until a request arrives or the timeout expires - the loop is
        # necessary to accommodate early wakeups due to EINTR.
        with _ServerSelector() as selector:
            selector.register(self, selectors.EVENT_READ)

            while True:
                ready = selector.select(timeout)
                if ready:
                    return self._handle_request_noblock()
                else:
                    if timeout is not None:
                        timeout = deadline - time()
                        if timeout < 0:
                            return self.handle_timeout()

    def _handle_request_noblock(self):
        """Handle one request, without blocking.

        I assume that selector.select() has returned that the socket is
        readable before this function was called, so there should be no risk of
        blocking in get_request().
        """
        try:
            request, client_address = self.get_request() #self.socket.accept()所以request相当于连接conn
        except OSError:
            return
        if self.verify_request(request, client_address):
            try:
                self.process_request(request, client_address)
            except:
                self.handle_error(request, client_address)
                self.shutdown_request(request)
        else:
            self.shutdown_request(request)

    def handle_timeout(self):
        """Called if no new request arrives within self.timeout.

        Overridden by ForkingMixIn.
        """
        pass

    def verify_request(self, request, client_address):
        """Verify the request.  May be overridden.

        Return True if we should proceed with this request.

        """
        return True

    def process_request(self, request, client_address):
        """Call finish_request.

        Overridden by ForkingMixIn and ThreadingMixIn.

        """
        self.finish_request(request, client_address)
        self.shutdown_request(request)

    def server_close(self):
        """Called to clean-up the server.

        May be overridden.

        """
        pass

    def finish_request(self, request, client_address):
        """Finish one request by instantiating RequestHandlerClass."""
        self.RequestHandlerClass(request, client_address, self)

    def shutdown_request(self, request):
        """Called to shutdown and close an individual request."""
        self.close_request(request)

    def close_request(self, request):
        """Called to clean up an individual request."""
        pass

    def handle_error(self, request, client_address):
        """Handle an error gracefully.  May be overridden.

        The default is to print a traceback and continue.

        """
        print(‘-‘*40)
        print(‘Exception happened during processing of request from‘, end=‘ ‘)
        print(client_address)
        import traceback
        traceback.print_exc() # XXX But this goes to stderr!
        print(‘-‘*40)

class ThreadingMixIn:
    """Mix-in class to handle each request in a new thread."""

    # Decides how threads will act upon termination of the
    # main process
    daemon_threads = False

    def process_request_thread(self, request, client_address):
        """Same as in BaseServer but as a thread.

        In addition, exception handling is done here.

        """
        try:
            self.finish_request(request, client_address)
            self.shutdown_request(request)
        except:
            self.handle_error(request, client_address)
            self.shutdown_request(request)

    def process_request(self, request, client_address):
        """Start a new thread to process the request."""
        t = threading.Thread(target = self.process_request_thread,
                             args = (request, client_address))
        t.daemon = self.daemon_threads
        t.start()

class BaseRequestHandler:

    """Base class for request handler classes.

    This class is instantiated for each request to be handled.  The
    constructor sets the instance variables request, client_address
    and server, and then calls the handle() method.  To implement a
    specific service, all you need to do is to derive a class which
    defines a handle() method.

    The handle() method can find the request as self.request, the
    client address as self.client_address, and the server (in case it
    needs access to per-server information) as self.server.  Since a
    separate instance is created for each request, the handle() method
    can define other arbitrary instance variables.

    """

    def __init__(self, request, client_address, server):
        self.request = request
        self.client_address = client_address
        self.server = server
        self.setup()
        try:
            self.handle()
        finally:
            self.finish()

    def setup(self):
        pass

    def handle(self):
        pass

    def finish(self):
        pass