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socket

1.      socket

Source code: Lib/socket.py

This module provides access to the BSD socket interface. It is available on all modern Unix systems, Windows, MacOS, and probably additional platforms.

The Python interface is a straightforward transliteration of the Unix system call and library interface for sockets to Python’s object-oriented style: the socket() function returns a socket object whose methods implement the various socket system calls. Parameter types are somewhat higher-level than in the C interface: as with read() and write() operations on Python files, buffer allocation on receive operations is automatic, and buffer length is implicit on send operations.

简单来说，它只是对底层进行了简单的封装；返回一个socket对象，可以执行系统调用。

参数类别比C接口中的封装程序稍高一些：与文件的read()和write()操作一样，接收操作的缓冲区分配是自动的，而发送操作的缓冲区长度是隐式的。

1.1.    Socket families

Depending on the system and the build options, various socket families are supported by this module.

The address format required by a particular socket object is automatically selected based on the address family specified when the socket object was created.

可根据所给出的地址类型自动选择套接字类型。

常用地址类型如下：

socket families：

　　AF_UNIX  unix本机之间进行通信

　　AF_INET  使用IPv4

　　AF_INET6  使用IPv6

socket types：

　　SOCK_STREAM          # TCP套接字类型

　　SOCK_DGRAM　　　# UDP套接字类型

　　SOCK_RAW      #原始套接字类型，这个套接字比较强大,创建这种套接字可以监听网卡上的所有数据帧

　　SOCK_RDM  #是一种可靠的UDP形式，即保证交付数据报但不保证顺序。SOCK_RAM用来提供对原始协议的低级访问，在需要执行某些特殊操作时使用，如发送ICMP报文。SOCK_RAM通常仅限于高级用户或管理员运行的程序使用。

其它具体可见相关文档。

1.2.    Functions

1.2.1.   Creating sockets

The following functions all create socket objects.

socket.socket(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 AF_INET (the default), AF_INET6, AF_UNIX, AF_CAN, AF_PACKET, or AF_RDS. The socket type should be SOCK_STREAM (the default), SOCK_DGRAM, SOCK_RAW or perhaps one of the other SOCK_ constants. The protocol number is usually zero and may be omitted or in the case where the address family is AF_CAN the protocol should be one of CAN_RAW, CAN_BCM or CAN_ISOTP.

If fileno is specified, the values for family, type, and proto are auto-detected from the specified file descriptor. Auto-detection can be overruled by calling the function with explicit family, type, or proto arguments. This only affects how Python represents e.g. the return value of socket.getpeername() but not the actual OS resource. Unlike socket.fromfd(), fileno will return the same socket and not a duplicate. This may help close a detached socket using socket.close().

The newly created socket is non-inheritable.

socket对象不可继承。

socket.socketpair([family[, type[, proto]]])

Build a pair of connected socket objects using the given address family, socket type, and protocol number. Address family, socket type, and protocol number are as for the socket() function above. The default family is AF_UNIX if defined on the platform; otherwise, the default is AF_INET.

socket.create_connection(address[, timeout[, source_address]])

Connect to a TCP service listening on the Internet address (a 2-tuple (host, port)), and return the socket object. This is a higher-level function than socket.connect(): if host is a non-numeric hostname, it will try to resolve it for both AF_INET and AF_INET6, and then try to connect to all possible addresses in turn until a connection succeeds. This makes it easy to write clients that are compatible to both IPv4 and IPv6.

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 getdefaulttimeout() is used.

If supplied, source_address must be a 2-tuple (host, port) for the socket to bind to as its source address before connecting. If host or port are ‘’ or 0 respectively the OS default behavior will be used.

socket.fromfd(fd, family, type, proto=0)

Duplicate the file descriptor fd (an integer as returned by a file object’s fileno() method) and build a socket object from the result. Address family, socket type and protocol number are as for the socket() function above. The file descriptor should refer to a socket, but this is not checked — subsequent operations on the object may fail if the file descriptor is invalid. This function is rarely needed, but can be used to get or set socket options on a socket passed to a program as standard input or output (such as a server started by the Unix inet daemon). The socket is assumed to be in blocking mode.

The newly created socket is non-inheritable.

1.2.2.   other functions

一些功能函数

socket.close(fd)

Close a socket file descriptor. This is like os.close(), but for sockets. On some platforms (most noticeable Windows) os.close() does not work for socket file descriptors.

socket.getaddrinfo(host, port, family=0, type=0, proto=0, flags=0)

socket.gethostbyname(hostname)

1.3.    socket objects

对象方法，基本含义都可以看名猜意，具体见相关文档。

1.4.    Notes on socket timeouts

A socket object can be in one of three modes: blocking, non-blocking, or timeout. Sockets are by default always created in blocking mode, but this can be changed by calling setdefaulttimeout().

In blocking mode, operations block until complete or the system returns an error (such as connection timed out).

In non-blocking mode, operations fail (with an error that is unfortunately system-dependent) if they cannot be completed immediately: functions from the select can be used to know when and whether a socket is available for reading or writing.

In timeout mode, operations fail if they cannot be completed within the timeout specified for the socket (they raise a timeout exception) or if the system returns an error.

1.5.    案例1

使用socket传输文件。

# server
# 使用socket传输文件
import select
import socket
import queue
from time import sleep


def socket_service():
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # get hostname
    host = socket.gethostname()
    # set port
    port = 9009
    try:
        s.bind((host, port))
        s.listen(3)
        c, addr = s.accept()
    except socket.error as msg:
        print(msg)
        exit(1)

    print(‘server ready, waiting for connetion...‘)

    fi = open(‘3.jpg‘,‘wb‘)
    while True:
        print(‘connetion addr:‘, addr)
        #c.send(‘first socket message.‘.encode())
        data = c.recv(1024)
        if not data:
            break
        fi.write(data)

    fi.close()
    c.close()
    s.close()

if __name__ == ‘__main__‘:
    #pr_type(‘s‘)
    socket_service()

# client
# 使用socket传输文件
import socket

def socket_client():
    s = socket.socket()
    host = socket.gethostname()
    port = 9009

    s.connect((host, port))
    f = open(‘2.jpg‘, ‘rb‘)
    while 1:
        data = f.read(1024)
        if not data:
            break
        s.send(data)
    f.close()
    s.close()


if __name__ == ‘__main__‘:
    #pr_type(‘s‘)
    socket_client()

1.6.    案例2

socket一对多

测试方法：

相差2秒，依次运行三个client脚本

测试结果描述：

比较长，简单描述；

三个脚本均会每间隔1秒发送一条消息至sever，

console中看到第一个脚本的所有消息是间隔1秒显示；

第二个脚本的所有消息是瞬间打印

第三个脚本前面部分消息是瞬间打印，后面部分消息是间隔打印。

测试结果解析：

1. 一对多不可以同时实现，只能是一对一结束后，另一个client连接；
2. 根据结果推理，socket底层会接收所有信息，但的ython层级只会同时处理一个socket，待一个socket断开连接后再处理下一个。

#coding:utf-8

# server
# 使用socket传输文件
import select
import socket
import queue
from time import sleep


def socket_service():
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    # get hostname
    host = socket.gethostname()
    # set port
    port = 9009

    try:
        s.bind((host, port))
        s.listen(3)
        c, addr = s.accept()
        print(‘www‘)
    except socket.error as msg:
        print(msg)
        exit(1)
    else:
        print(‘server ready, waiting for connetion...‘)

    print(‘wwww‘)
    print(c)
    while True:
        print(‘connetion addr:‘, addr)
        #c.send(‘first socket message.‘.encode())
        data = c.recv(1024)
        print(‘data reciveing: ‘, data.decode())
        if not data:
            #break
            print(‘no data‘)
            c, addr = s.accept()
            print(c)

    c.close()
    s.close()

if __name__ == ‘__main__‘:
    #pr_type(‘s‘)
    socket_service()

# client
# 使用socket传输文件
import socket
import time

def socket_client():
    s = socket.socket()
    host = socket.gethostname()
    port = 9009

    s.connect((host, port))
    print(s.getpeername())
    f = open(‘2.txt‘, ‘r‘, encoding=‘utf-8‘)
    while 1:
        data = f.readline()
        if not data:
            break
        s.send(data.encode())
        time.sleep(1)

    f.close()
    s.close()


if __name__ == ‘__main__‘:
    #pr_type(‘s‘)
    socket_client()

socket

标签：相关   for   return   encode   ipv4   lib   unix   NPU   exp   

原文地址：https://www.cnblogs.com/wodeboke-y/p/11241472.html