• 粘包：发送方发送两个字符串”hello”, ”world”，接收方却一次性接收到了”helloworld”
• 分包：发送方发送字符串”helloworld”，接收方却接收到了两个字符串”hello”和”world”

1 服务端

import socket
import struct
HOST = ''
PORT = 1234
# FIFO消息队列
dataBuffer = bytes()
# 自定义消息头的长度
headerSize = 12
# 定义数据包的个数
sn = 0
# 正文数据处理
def dataHandle(headPack, body):
    global sn
    sn += 1
    print(f"第{sn}个数据包")
    print(body.decode())
    print("\n")
if __name__ == '__main__':
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.bind((HOST, PORT))
        s.listen(1)
        conn, addr = s.accept()
        with conn:
            print('Connected by', addr)
            while True:
                data = conn.recv(1024)
                if data:
                    # 把数据存入缓冲区，类似于push数据
                    dataBuffer += data
                    while True:
                        if len(dataBuffer) < headerSize:
                            print("数据包（%s Byte）小于消息头部长度，跳出小循环" % len(dataBuffer))
                            break
                        # 读取包头
                        # struct中!代表Network order，3I代表3个unsigned int数据
                        headPack = struct.unpack('!3I', dataBuffer[:headerSize])
                        bodySize = headPack[1]
                        # 分包情况处理，跳出函数继续接收数据
                        if len(dataBuffer) < headerSize+bodySize :
                            print("数据包（%s Byte）不完整（总共%s Byte），跳出小循环" % (len(dataBuffer), headerSize+bodySize))
                            break
                        # 读取消息正文的内容
                        body = dataBuffer[headerSize:headerSize+bodySize]
                        # 数据处理
                        dataHandle(headPack, body)
                        # 数据出列
                        dataBuffer = dataBuffer[headerSize+bodySize:] # 获取下一个数据包，类似于把数据pop出

2 客户端

import socket
import time
import struct
import json
host = "localhost"
port = 1234
ADDR = (host, port)
if __name__ == '__main__':
    client = socket.socket()
    client.connect(ADDR)
    # 正常数据包定义
    ver = 1
    body = json.dumps(dict(hello="world"))
    print(body)
    cmd = 101
    header = [ver, body.__len__(), cmd]
    headPack = struct.pack("!3I", *header)
    sendData1 = headPack+body.encode()
    # 分包数据定义
    ver = 2
    body = json.dumps(dict(hello="world2"))
    print(body)
    cmd = 102
    header = [ver, body.__len__(), cmd]
    headPack = struct.pack("!3I", *header)
    sendData2_1 = headPack+body[:2].encode()
    sendData2_2 = body[2:].encode()
    # 粘包数据定义
    ver = 3
    body1 = json.dumps(dict(hello="world3"))
    print(body1)
    cmd = 103
    header = [ver, body1.__len__(), cmd]
    headPack1 = struct.pack("!3I", *header)
    ver = 4
    body2 = json.dumps(dict(hello="world4"))
    print(body2)
    cmd = 104
    header = [ver, body2.__len__(), cmd]
    headPack2 = struct.pack("!3I", *header)
    sendData3 = headPack1+body1.encode()+headPack2+body2.encode()
    # 正常数据包
    client.send(sendData1)
    time.sleep(3)
    # 分包测试
    client.send(sendData2_1)
    time.sleep(0.2)
    client.send(sendData2_2)
    time.sleep(3)
    # 粘包测试
    client.send(sendData3)
    time.sleep(3)
    client.close()