非阻塞IO发送http请求

import socket
from urllib.parse import urlparse
from selectors import DefaultSelector, EVENT_READ, EVENT_WRITE
def get_url(url):
    #通过socket请求html
    url = urlparse(url)
    host = url.netloc
    path = url.path
    if path == "":
        path = "/"

    #建立socket连接
    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    client.setblocking(False)
    try:
        #如果不try的话 则会有异常，因为链接还没建立好
        #BlockingIOError: [WinError 10035] 无法立即完成一个非阻止性套接字操作。
        client.connect((host, 80)) #阻塞不会消耗cpu
    except BlockingIOError as e:
        pass

    #不停的询问连接是否建立好， 需要while循环不停的去检查状态
    #做计算任务或者再次发起其他的连接请求

    while True:
        try:
            #发送http请求
            #请求行
请求头

请求体
            client.send("GET {} HTTP/1.1
Host:{}
Connection:close

".format(path, host).encode("utf8"))
            break
        except OSError as e:
            pass


    data = b""
    while True:
        try:
            d = client.recv(1024)
        except BlockingIOError as e:
            continue
        if d:
            data += d
        else:
            break

    data = data.decode("utf8")
    html_data = data.split("

")[1]
    print(html_data)
    client.close()


get_url('http://www.baidu.com')

响应结果：

响应行

响应头

...........

响应体

"C:Program Filespython3.5python.exe" E:/pythoncode/day07/01.py
HTTP/1.1 200 OK
Accept-Ranges: bytes
Cache-Control: no-cache
Content-Length: 14615
Content-Type: text/html
Date: Thu, 16 Aug 2018 08:52:32 GMT
Etag: "5b56b4a8-3917"
Last-Modified: Tue, 24 Jul 2018 05:10:00 GMT
P3p: CP=" OTI DSP COR IVA OUR IND COM "
Pragma: no-cache
Server: BWS/1.1
Set-Cookie: BAIDUID=DCD58464E426E409DBF02803181718DB:FG=1; expires=Thu, 31-Dec-37 23:55:55 GMT; max-age=2147483647; path=/; domain=.baidu.com
Set-Cookie: BIDUPSID=DCD58464E426E409DBF02803181718DB; expires=Thu, 31-Dec-37 23:55:55 GMT; max-age=2147483647; path=/; domain=.baidu.com
Set-Cookie: PSTM=1534409552; expires=Thu, 31-Dec-37 23:55:55 GMT; max-age=2147483647; path=/; domain=.baidu.com
Vary: Accept-Encoding
X-Ua-Compatible: IE=Edge,chrome=1
Connection: close

<!DOCTYPE html><!--STATUS OK-->
<html>
<head>
	<meta http-equiv="content-type" content="text/html;charset=utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=Edge">
	<link rel="dns-prefetch" href="//s1.bdstatic.com"/>
	<link rel="dns-prefetch" href="//t1.baidu.com"/>
	<link rel="dns-prefetch" href="//t2.baidu.com"/>
	<link rel="dns-prefetch" href="//t3.baidu.com"/>
	<link rel="dns-prefetch" href="//t10.baidu.com"/>
	<link rel="dns-prefetch" href="//t11.baidu.com"/>
	<link rel="dns-prefetch" href="//t12.baidu.com"/>
	<link rel="dns-prefetch" href="//b1.bdstatic.com"/>