异步通信WebSocket

        - 服务端（socket服务端）
            1. 服务端开启socket，监听IP和端口
            3. 允许连接
            * 5. 服务端接收到特殊值【加密sha1,特殊值,migic string="258EAFA5-E914-47DA-95CA-C5AB0DC85B11"】
            * 6. 加密后的值发送给客户端
                        
        - 客户端（浏览器）
            2. 客户端发起连接请求（IP和端口）
            * 4. 客户端生成一个xxx，【加密sha1,特殊值,migic string="258EAFA5-E914-47DA-95CA-C5AB0DC85B11"】,向服务端发送一段特殊值
            * 7. 客户端接收到加密的值

import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((‘127.0.0.1‘, 8002))
sock.listen(5)
# 等待用户连接
conn, address = sock.accept()
...
...
...

import socket
 
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((‘127.0.0.1‘, 8002))
sock.listen(5)
# 获取客户端socket对象
conn, address = sock.accept()
# 获取客户端的【握手】信息
data = conn.recv(1024)
...
...
...
conn.send(‘响应【握手】信息‘)　　

GET /chatsocket HTTP/1.1
Host: 127.0.0.1:8002
Connection: Upgrade
Pragma: no-cache
Cache-Control: no-cache
Upgrade: websocket
Origin: http://localhost:63342
Sec-WebSocket-Version: 13
Sec-WebSocket-Key: mnwFxiOlctXFN/DeMt1Amg==
Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
...
...

import socket
import base64
import hashlib
 
def get_headers(data):
    """
    将请求头格式化成字典
    :param data:
    :return:
    """
    header_dict = {}
    data = str(data, encoding=‘utf-8‘)
 
    for i in data.split(‘\r\n‘):
        print(i)
    header, body = data.split(‘\r\n\r\n‘, 1)
    header_list = header.split(‘\r\n‘)
    for i in range(0, len(header_list)):
        if i == 0:
            if len(header_list[i].split(‘ ‘)) == 3:
                header_dict[‘method‘], header_dict[‘url‘], header_dict[‘protocol‘] = header_list[i].split(‘ ‘)
        else:
            k, v = header_list[i].split(‘:‘, 1)
            header_dict[k] = v.strip()
    return header_dict
 
 
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
sock.bind((‘127.0.0.1‘, 8002))
sock.listen(5)
 
conn, address = sock.accept()
data = conn.recv(1024)
headers = get_headers(data) # 提取请求头信息
# 对请求头中的sec-websocket-key进行加密
response_tpl = "HTTP/1.1 101 Switching Protocols\r\n"       "Upgrade:websocket\r\n"       "Connection: Upgrade\r\n"       "Sec-WebSocket-Accept: %s\r\n"       "WebSocket-Location: ws://%s%s\r\n\r\n"
magic_string = ‘258EAFA5-E914-47DA-95CA-C5AB0DC85B11‘
value = headers[‘Sec-WebSocket-Key‘] + magic_string
ac = base64.b64encode(hashlib.sha1(value.encode(‘utf-8‘)).digest())    #获取加密后的字符串二进制
response_str = response_tpl % (ac.decode(‘utf-8‘), headers[‘Host‘], headers[‘url‘])
# 响应【握手】信息
conn.send(bytes(response_str, encoding=‘utf-8‘))
...
...
...

0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len |    Extended payload length    |
|I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
|N|V|V|V|       |S|             |   (if payload len==126/127)   |
| |1|2|3|       |K|             |                               |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
|     Extended payload length continued, if payload len == 127  |
+ - - - - - - - - - - - - - - - +-------------------------------+
|                               |Masking-key, if MASK set to 1  |
+-------------------------------+-------------------------------+
| Masking-key (continued)       |          Payload Data         |
+-------------------------------- - - - - - - - - - - - - - - - +
:                     Payload Data continued ...                :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
|                     Payload Data continued ...                |
+---------------------------------------------------------------+

第一个字节

最高位用于描述消息是否结束,如果为1则该消息为消息尾部,如果为零则还有后续数据包;后面3位是用于扩展定义的,如果没有扩展约定的情况则必须为0.可以通过以下c#代码方式得到相应值


mDataPackage.IsEof = (data[start] >> 7) > 0;
最低4位用于描述消息类型,消息类型暂定有15种,其中有几种是预留设置.c#代码可以这样得到消息类型:

int type = data[start] & 0xF;
mDataPackage.Type = (PackageType)type;
第二个字节

消息的第二个字节主要用一描述掩码和消息长度,最高位用0或1来描述是否有掩码处理,可以通过以下c#代码方式得到相应值


bool hasMask = (data[start] >>7) > 0;
剩下的后面7位用来描述消息长度,由于7位最多只能描述127所以这个值会代表三种情况,一种是消息内容少于126存储消息长度,如果消息长度少于UINT16的情况此值为126,当消息长度大于UINT16的情况下此值为127;这两种情况的消息长度存储到紧随后面的byte[],分别是UINT16(2位byte)和UINT64(4位byte).可以通过以下c#代码方式得到相应值


mPackageLength = (uint)(data[start] & 0x7F);
start++;
if (mPackageLength == 126)
{
    mPackageLength = BitConverter.ToUInt16(data, start);
    start = start + 2;
}
else if (mPackageLength == 127)
{
    mPackageLength = BitConverter.ToUInt64(data, start);
    start = start + 8;
}
如果存在掩码的情况下获取4位掩码值:


if (hasMask)
{
    mDataPackage.Masking_key = new byte[4];
    Buffer.BlockCopy(data, start, mDataPackage.Masking_key, 0, 4);
           
    start = start + 4;
    count = count - 4;
}
获取消息体

当得到消息体长度后就可以获取对应长度的byte[],有些消息类型是没有长度的如%x8 denotes a connection close.对于Text类型的消息对应的byte[]是相应字符的UTF8编码.获取消息体还有一个需要注意的地方就是掩码,如果存在掩码的情况下接收的byte[]要做如下转换处理:


if (mDataPackage.Masking_key != null)
    {
        int length = mDataPackage.Data.Count;
        for (var i = 0; i