背景
目前看到实现websocket的框架的
- django的channels
- flask
- sanic
好奇，用python怎样写一个websokcet服务器，以及socket如何与应用框一起启动
后记
- accept 与recv是阻塞模式，调用时候，同时新开一个threading解决同步阻塞的问题
- while True 要写在 sock.accept() 之前，因为在要等不同的socket连接，如果写在这之后，只能有一个socket连接
- 首次连接通过http建立，之后直接互相通信 while True 同样要写在conn.recv(8094) 之前， 因为要不停的通信
- 整个socket通信要写两次 while True
- werkzeug与websocket同时启动， 在主进程内，各开一个子进程即可
6.在此基础上可以按需扩展，如改成python3 的async写法 ， 引用更高级别的库websocket或python3的protocol等。万变不离其宗，从python层面，这是比较底层的写法，其它的写法大多是在此基础上封装的。
第一版后端
import socket
import struct
import hashlib
import base64
def get_headers(data):
headers = {}
data = str(data, encoding="utf-8")
header, body = data.split("\r\n\r\n", 1)
header_list = header.split("\r\n")
for i in header_list:
i_list = i.split(":", 1)
if len(i_list) >= 2:
headers[i_list[0]] = "".join(i_list[1::]).strip()
else:
i_list = i.split(" ", 1)
if i_list and len(i_list) == 2:
headers["method"] = i_list[0]
headers["protocol"] = i_list[1]
return headers
def parse_payload(payload):
payload_len = payload[1] & 127
if payload_len == 126:
extend_payload_len = payload[2:4]
mask = payload[4:8]
decoded = payload[8:]
elif payload_len == 127:
extend_payload_len = payload[2:10]
mask = payload[10:14]
decoded = payload[14:]
else:
extend_payload_len = None
mask = payload[2:6]
decoded = payload[6:]
# 这里我们使用字节将数据全部收集，再去字符串编码，这样不会导致中文乱码
bytes_list = bytearray()
for i in range(len(decoded)):
# 解码方式
chunk = decoded[i] ^ mask[i % 4]
bytes_list.append(chunk)
body = str(bytes_list, encoding='utf-8')
return body
def send_msg(conn, msg_bytes):
token = b"\x81"
length = len(msg_bytes)
if length < 126:
token += struct.pack("B", length)
elif length <= 0xFFFF:
token += struct.pack("!BH", 126, length)
else:
token += struct.pack("!BQ", 127, length)
msg = token + msg_bytes
conn.sendall(msg)
return True
def server_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", 10083))
sock.listen(5)
conn, addr = sock.accept()
print(conn)
data = conn.recv(8096)
headers = get_headers(data)
# 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\r\n\r\n"
magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
if headers.get('Sec-WebSocket-Key'):
value = headers['Sec-WebSocket-Key'] + magic_string
ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest())
response_str = response_tpl % (ac.decode('utf-8'), headers.get("Host"))
conn.sendall(bytes(response_str, encoding="utf-8"))
while True:
data_1 = conn.recv(8096)
data_2 = parse_payload(data_1)
print(data_2)
send_msg(conn, b"test")
if __name__ == "__main__":
server_socket()
web 端
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
<style>
*{
margin: 0;
padding: 0;
}
.message{
width: 60%;
margin: 0 10px;
display: inline-block;
text-align: center;
height: 40px;
line-height: 40px;
font-size: 20px;
border-radius: 5px;
border: 1px solid #B3D33F;
}
.form{
width:100%;
position: fixed;
bottom: 300px;
left: 0;
}
.connect{
height: 40px;
vertical-align: top;
/* padding: 0; */
width: 80px;
font-size: 20px;
border-radius: 5px;
border: none;
background: #B3D33F;
color: #fff;
}
</style>
<script src="https://cdn.bootcss.com/jquery/3.4.1/jquery.js"></script>
</head>
<body>
<ul id="content"></ul>
<form class="form">
<input type="text" placeholder="请输入发送的消息" class="message" id="message"/>
<input type="button" value="发送" id="send" class="connect"/>
<input type="button" value="连接" id="connect" class="connect"/>
</form>
<script>
var oUl=document.getElementById('content');
var oConnect=document.getElementById('connect');
var oSend=document.getElementById('send');
var oInput=document.getElementById('message');
var ws=null;
oConnect.onclick=function(){
ws=new WebSocket('ws://127.0.0.1:10083');
ws.onopen=function(){
oUl.innerHTML+="<li>客户端已连接</li>";
}
ws.onmessage=function(evt){
console.log("fdsa")
oUl.innerHTML+="<li>"+evt.data+"</li>";
}
ws.onclose=function(){
oUl.innerHTML+="<li>客户端已断开连接</li>";
};
ws.onerror=function(evt){
oUl.innerHTML+="<li>"+evt.data+"</li>";
};
};
oSend.onclick=function(){
if(ws){
ws.send($("#message").val())
}
}
</script>
</body>
</html>
效果
image.png
image.png
这版有些问题
- 客户端断开，服务端就挂了
- 单线程.....
改进版
import socket
import struct
import hashlib
import base64
import threading
def get_headers(data):
headers = {}
data = str(data, encoding="utf-8")
header, body = data.split("\r\n\r\n", 1)
header_list = header.split("\r\n")
for i in header_list:
i_list = i.split(":", 1)
if len(i_list) >= 2:
headers[i_list[0]] = "".join(i_list[1::]).strip()
else:
i_list = i.split(" ", 1)
if i_list and len(i_list) == 2:
headers["method"] = i_list[0]
headers["protocol"] = i_list[1]
return headers
def parse_payload(payload):
payload_len = payload[1] & 127
if payload_len == 126:
extend_payload_len = payload[2:4]
mask = payload[4:8]
decoded = payload[8:]
elif payload_len == 127:
extend_payload_len = payload[2:10]
mask = payload[10:14]
decoded = payload[14:]
else:
extend_payload_len = None
mask = payload[2:6]
decoded = payload[6:]
# 这里我们使用字节将数据全部收集，再去字符串编码，这样不会导致中文乱码
bytes_list = bytearray()
for i in range(len(decoded)):
# 解码方式
chunk = decoded[i] ^ mask[i % 4]
bytes_list.append(chunk)
body = str(bytes_list, encoding='utf-8')
return body
def send_msg(conn, msg_bytes):
# 接收的第一字节，一般都是x81不变
first_byte = b"\x81"
length = len(msg_bytes)
if length < 126:
first_byte += struct.pack("B", length)
elif length <= 0xFFFF:
first_byte += struct.pack("!BH", 126, length)
else:
first_byte += struct.pack("!BQ", 127, length)
msg = first_byte + msg_bytes
conn.sendall(msg)
return True
sock_pool = []
def handler_accept(sock):
while True:
conn, addr = sock.accept()
data = conn.recv(8096)
headers = get_headers(data)
# 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\r\n\r\n"
# 第一次连接发回报文
magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
if headers.get('Sec-WebSocket-Key'):
value = headers['Sec-WebSocket-Key'] + magic_string
ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest())
response_str = response_tpl % (ac.decode('utf-8'), headers.get("Host"))
conn.sendall(bytes(response_str, encoding="utf-8"))
t = threading.Thread(target=handler_msg, args=(conn, ))
t.start()
def handler_msg(conn):
with conn as c:
while True:
data_recv = c.recv(8096)
if data_recv[0:1] == b"\x81":
data_parse = parse_payload(data_recv)
print(data_parse)
send_msg(c, bytes("recv: {}".format(data_parse), encoding="utf-8"))
def server_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", 10083))
sock.listen(5)
t = threading.Thread(target=handler_accept(sock))
t.start()
# data = conn.recv(8096)
# headers = get_headers(data)
#
# # 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\r\n\r\n"
#
# # 第一次连接发回报文
# magic_string = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
# if headers.get('Sec-WebSocket-Key'):
# value = headers['Sec-WebSocket-Key'] + magic_string
#
# ac = base64.b64encode(hashlib.sha1(value.encode('utf-8')).digest())
# response_str = response_tpl % (ac.decode('utf-8'), headers.get("Host"))
# conn.sendall(bytes(response_str, encoding="utf-8"))
if __name__ == "__main__":
server_socket()
参考
websocket例子
https://www.cnblogs.com/ssyfj/p/9245150.html
websocket 理论理解的例子
https://www.cnblogs.com/IT-Scavenger/p/9435405.html
一个不错的例子
https://blog.csdn.net/qq_39687901/article/details/81531101
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