Web应用
对于所有的web应用，本质上其实就是一个socket服务端，用户的浏览器其实就是一个socket客户端
import socketdef handle_request(client): ???buf = client.recv(1024) ???client.send("HTTP/1.1 200 OK\r\n\r\n".encode("utf8")) ???client.send("<h1 style=‘color:red‘>Hello, yuan</h1>".encode("utf8"))def main(): ???sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) ???sock.bind((‘localhost‘,8001)) ???sock.listen(5) ???while True: ???????connection, address = sock.accept() ???????handle_request(connection) ???????connection.close()if __name__ == ‘__main__‘: ???main()最简单的web应用就是先把HTML用文件保存好，用一个现成的HTTP服务器软件，接受用户请求，接受用户请求并返回
如果要动态生成HTML，就需要把上述步骤自己来实现。不过，接受HTTP请求、解析HTTP请求、发送HTTP响应都是苦力活，如果我们自己来写这些底层代码，还没开始写动态HTML呢，就得花个把月去读HTTP规范。
正确的做法是底层代码由专门的服务器软件实现，我们用Python专注于生成HTML文档。因为我们不希望接触到TCP连接、HTTP原始请求和响应格式，所以，需要一个统一的接口，让我们专心用Python编写Web业务。
这个接口就是WSGI：Web Server Gateway Interface。
wsgiref模块
from wsgiref.simple_server import make_serverdef application(environ, start_response): ???start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘)]) ???return [b‘<h1>Hello, web!</h1>‘]httpd = make_server(‘‘, 8080, application)print(‘Serving HTTP on port 8000...‘)# 开始监听HTTP请求:httpd.serve_forever()
对比socketserver模块
DIY一个自己的web框架
manage.py
from wsgiref.simple_server import make_server# ?request ???????????responsefrom app01.views import *from app01 import urlsdef routers(): ???URLpattern=urls.URLpattern ???return URLpatterndef applications(environ,start_response): ???path=environ.get("PATH_INFO") ???print("path",path) ???start_response(‘200 OK‘, [(‘Content-Type‘, ‘text/html‘),(‘Charset‘, ‘utf8‘)]) ???urlpattern=routers() ???func=None ???for item in urlpattern: ???????if path==item[0]: ???????????func=item[1] ???????????break ???if func: ???????return [func(environ)] ???else: ???????return [b"<h1>404!<h1>"] ???# return [b"<h1>hello world<h1>"]if __name__ == ‘__main__‘: ???t=make_server("",8810,applications) ???print("server is working...") ???t.serve_forever()urls
from app01.views import *URLpattern = ( ???("/login/", login),)views
import pymysqlfrom urllib.parse import parse_qsdef login(request): ???if request.get("REQUEST_METHOD")=="POST": ???????print("+++++",request) ???????#当请求方式是GET时 ???????# user_union,pwd_union=request.get("QUERY_STRING").split("&") ???????# _,user=user_union.split("=") ???????# _,pwd=pwd_union.split("=") ???????# 环境变量 CONTENT_LENGTH 可能是空值 或者 值丢失 ???????try: ???????????request_body_size = int(request.get(‘CONTENT_LENGTH‘, 0)) ???????except (ValueError): ???????????request_body_size = 0 ???????# 当请求方式是POST时, 变量将会被放在存在域wsgi.input文件中的HTTP请求信息中, 由WSGI 服务器一起发送. ???????request_body = request[‘wsgi.input‘].read(request_body_size) ???????d = parse_qs(request_body) ???????user=d.get(b"user")[0].decode("utf8") ???????pwd=d.get(b"pwd")[0].decode("utf8") ???????print("user",user,pwd) ???????#连接数据库 ???????conn = pymysql.connect(host=‘‘,port= 3306,user = ‘root‘,passwd=‘‘,db=‘s6‘) #db：库名 ???????#创建游标 ???????cur = conn.cursor() ???????SQL="select * from userinfo2 WHERE NAME =‘%s‘ AND PASSWORD =‘%s‘"%(user,pwd) ???????cur.execute(SQL) ???????if cur.fetchone(): ???????????f=open("templates/backend.html","rb") ???????????data=f.read() ???????????data=(data.decode("utf8"))%user ???????????return data.encode("utf8") ???????else: ????????????return b"user or pwd is wrong" ???else: ???????f = open("templates/login.html", "rb") ???????data = f.read() ???????f.close() ???????return datamodels
import pymysqlimport pymysql#连接数据库conn = pymysql.connect(host=‘‘,port= 3306,user = ‘root‘,passwd=‘‘,db=‘s6‘) #db：库名#创建游标cur = conn.cursor()# sql=‘‘‘# create table userinfo2(# ????????id INT PRIMARY KEY ,# ????????name VARCHAR(32) ,# ????????password VARCHAR(32)# )## ‘‘‘## cur.execute(sql)## cur.executemany("insert into userinfo2 values(%s,%s,%s)", [(1,"yuan","123"),# ??????????????????????????????????????????????????????????(2,"alex","456"),# ??????????????????????????????????????????????????????????(3,"egon","789")])cur.execute("select * from userinfo2 WHERE NAME=‘yuan‘ AND PASSWORD =‘123‘")#提交conn.commit()#关闭指针对象cur.close()#关闭连接对象conn.close()web应用与web框架（Day65）
原文地址：http://www.cnblogs.com/shaojiafeng/p/7717622.html