WSGI Web服务器网关接口
WSGI主要规定了Web服务器如何与Web应用程序进行通信，以及如何将Web应用程序链接在一起来处理一个请求。
wsgiref Python中的WSGI参考模块
一、WSGI 应用程序端：
1、 根据WSGI定义，应用程序应该是可调用对象
2、该可调用对象必须有两个固定参数：一个是含有服务器环境变量的字典，另一个是可调用对象，该对象使用HTTP状态码和会返回给客户端的HTTP头来初始化响应
environ 变量包含一些熟悉的环境变量，如HTTP_HOST，HTTP_USER_AGENT，REMOTE_ADDR，REQUEST_METHOD，SERVER_PORT，部分如下：
Hello world! GATEWAY_INTERFACE = ‘CGI/1.1‘ HTTP_ACCEPT = ‘text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8‘ HTTP_ACCEPT_ENCODING = ‘gzip, deflate, br‘ HTTP_ACCEPT_LANGUAGE = ‘zh-CN,zh;q=0.9,en;q=0.8‘ HTTP_CONNECTION = ‘keep-alive‘ HTTP_HOST = ‘127.0.0.1:9999‘ HTTP_USER_AGENT = ‘Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36‘ QUERY_STRING = ‘‘ REMOTE_ADDR = ‘127.0.0.1‘ REQUEST_METHOD = ‘GET‘ SERVER_PORT = ‘9999‘ SERVER_PROTOCOL = ‘HTTP/1.1‘ SERVER_SOFTWARE = ‘WSGIServer/0.2‘
3、这个可调用对象必须返回一个可迭代对象用于组成响应
wsgiref参考库中有以下几个子模块：
* util -- 一些有用的功能和包装
* headers -- 管理响应头
* handlers -- 为server/gateway实现如何处理的基类
* simple_server -- 实现一个简单的WSGI HTTP服务器
* validate -- 位于应用程序和server之间检测错误的校验包装
二、WSGI HTTP Server端的使用
1. 启动一个简单的WSGI HTTP Server：
# 简单web 1
from wsgiref.simple_server import make_server
def demo_app(environ, start_response): #copy自simple_server模块
from io import StringIO
stdout = StringIO()
print("Hello world!", file=stdout)
print(file=stdout)
h = sorted(environ.items())
for k, v in h:
print(k, ‘=‘, repr(v), file=stdout)
start_response("200 OK", [(‘Content-Type‘, ‘text/plain; charset=utf-8‘)])
return [stdout.getvalue().encode("utf-8")]
ip = ‘127.0.0.1‘
port = 9999
server = make_server(ip, port, demo_app)
server.serve_forever()
server.server_close()
wsgiref.simple_server.make_server(host, port, app, server_class=WSGIServer, handler_class=WSGIRequestHandler)
启动一个WSGI服务器，必须传入host, port, app三个参数。
在运行这段程序之后，就已经实现了一个监听在9999端口的webServer，下面是服务端运行状态和浏览器中访问结果：
访问 http://127.0.0.1:9999/ #server端运行状态： 127.0.0.1 - - [26/Dec/2017 15:01:13] "GET / HTTP/1.1" 200 2128 127.0.0.1 - - [26/Dec/2017 15:01:13] "GET /favicon.ico HTTP/1.1" 200 2096 #浏览器访问结果： Hello world! Apple_PubSub_Socket_Render = ‘/private/tmp/com.apple.launchd.Gx10g4snot/Render‘ CLICOLOR = ‘1‘ CONTENT_LENGTH = ‘‘ CONTENT_TYPE = ‘text/plain‘ GATEWAY_INTERFACE = ‘CGI/1.1‘ GREP_OPTIONS = ‘--color=auto‘ HOME = ‘/Users/ihoney‘ HTTP_ACCEPT = ‘text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8‘ HTTP_ACCEPT_ENCODING = ‘gzip, deflate, br‘ HTTP_ACCEPT_LANGUAGE = ‘zh-CN,zh;q=0.9,en;q=0.8‘ HTTP_CONNECTION = ‘keep-alive‘ HTTP_HOST = ‘127.0.0.1:9999‘ HTTP_UPGRADE_INSECURE_REQUESTS = ‘1‘ HTTP_USER_AGENT = ‘Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36‘ LC_CTYPE = ‘zh_CN.UTF-8‘ ......
2. 自定义响应的网页内容：
# 简单web 2
from wsgiref.simple_server import make_server
def application(environ:dict,start_response):
# print(type(environ),environ)
html = "<h1>北京欢迎你</h1>"
# start_response("200 OK", [(‘Content-Type‘,‘text/plain; charset=utf-8‘)]) #文本格式
start_response("200 OK", [(‘Content-Type‘, ‘text/html; charset=utf-8‘)]) #html格式
return [html.encode()]
ip = ‘127.0.0.1‘
port =9999
server = make_server(ip,port,application)
server.serve_forever()
server.server_close()
#运行结果：
127.0.0.1 - - [26/Dec/2017 15:38:55] "GET / HTTP/1.1" 200 24
127.0.0.1 - - [26/Dec/2017 15:38:55] "GET /favicon.ico HTTP/1.1" 200 24
浏览器访问结果：
simple_server 只是参考，不可用于生产环境。
三、QUERY_STRING 查询字符串的解析
1. 使用cgi模块：
# 简单web 3 使用cgi模块解析query_string
import cgi
from wsgiref.simple_server import make_server
def application(environ:dict,start_response):
qstr = environ.get("QUERY_STRING")
print(qstr)
# ?id=5&name=ihoney&age=18,19
print(cgi.parse_qs(qstr)) #字典,value为列表类型
print(cgi.parse_qsl(qstr)) #二元组列表
html = "<h1>北京欢迎你</h1>"
start_response("200 OK", [(‘Content-Type‘, ‘text/html; charset=utf-8‘)])
return [html.encode()]
ip = ‘127.0.0.1‘
port =9999
server = make_server(ip,port,application)
server.serve_forever()
server.server_close()
#浏览器访问http://127.0.0.1:9999/?id=5&name=ihoney&age=18,19
#运行结果：
127.0.0.1 - - [26/Dec/2017 15:51:17] "GET /?id=5&name=ihoney&age=18,19 HTTP/1.1" 200 24
id=5&name=ihoney&age=18,19
{‘age‘: [‘18,19‘], ‘name‘: [‘ihoney‘], ‘id‘: [‘5‘]}
[(‘id‘, ‘5‘), (‘name‘, ‘ihoney‘), (‘age‘, ‘18,19‘)]
在写的时候IDE工具就会提示CGI模块已经过期了，建议使用urllib库。
2. 使用urllib库
# 简单web 4 使用urllib模块解析query_string
from urllib import parse
from wsgiref.simple_server import make_server
def application(environ:dict,start_response):
qstr = environ.get("QUERY_STRING")
print(qstr)
# ?id=5&name=ihoney&age=18,19
print(parse.parse_qs(qstr)) #字典,value为列表类型
print(parse.parse_qsl(qstr)) #二元组列表
html = "<h1>北京欢迎你</h1>"
start_response("200 OK", [(‘Content-Type‘, ‘text/html; charset=utf-8‘)])
return [html.encode()]
ip = ‘127.0.0.1‘
port =9999
server = make_server(ip,port,application)
server.serve_forever()
server.server_close()
#浏览器访问：http://127.0.0.1:9999/?id=5&name=ihoney&age=18,19
#运行结果：
id=5&name=ihoney&age=18,19
{‘id‘: [‘5‘], ‘age‘: [‘18,19‘], ‘name‘: [‘ihoney‘]}
[(‘id‘, ‘5‘), (‘name‘, ‘ihoney‘), (‘age‘, ‘18,19‘)]
127.0.0.1 - - [26/Dec/2017 15:58:40] "GET /?id=5&name=ihoney&age=18,19 HTTP/1.1" 200 24
3. 使用第三方库webob
pip3 install webob
第三方库webob可以把环境数据的解析封装成对象，使用时直接调用。
3.1 webob.Request
#简单web 5，使用第三方库webob解析
from wsgiref.simple_server import make_server
from webob import Request, Response
def application(environ: dict, start_response):
request = Request(environ)
print(request.method)
print(request.path)
print(request.GET)
print(request.POST)
print(request.params)
print(request.query_string)
html = "<h1>北京欢迎你</h1>"
start_response("200 OK", [(‘Content-Type‘, ‘text/html; charset=utf-8‘)])
return [html.encode()]
ip = ‘127.0.0.1‘
port = 9999
server = make_server(ip, port, application)
server.serve_forever()
server.server_close()
#浏览器访问：http://127.0.0.1:9999/index.html?id=5&name=tom,jerry&age=17&age=18,19
#运行结果：
GET
/index.html
GET([(‘id‘, ‘5‘), (‘name‘, ‘tom,jerry‘), (‘age‘, ‘17‘), (‘age‘, ‘18,19‘)])
<NoVars: Not a form request>
NestedMultiDict([(‘id‘, ‘5‘), (‘name‘, ‘tom,jerry‘), (‘age‘, ‘17‘), (‘age‘, ‘18,19‘)])
id=5&name=tom,jerry&age=17&age=18,19
127.0.0.1 - - [26/Dec/2017 16:51:41] "GET /index.html?id=5&name=tom,jerry&age=17&age=18,19 HTTP/1.1" 200 24
3.2 webob.Resphone
#
from wsgiref.simple_server import make_server
from webob import Request, Response
def application(environ: dict, start_response):
res = Response("<h1>北京欢迎你</h1>")
return res(environ,start_response) #__call__
ip = ‘127.0.0.1‘
port = 9999
server = make_server(ip, port, application)
server.serve_forever()
server.server_close()
#浏览器访问：http://127.0.0.1:9999/index.html?id=5&name=tom,jerry&age=17&age=18,19
#运行结果：
127.0.0.1 - - [26/Dec/2017 18:08:03] "GET /index.html?id=5&name=tom,jerry&age=17&age=18,19 HTTP/1.1" 200 24
3.3 MultiDict
Request.GET、Request.POST 都是MultiDict字典
# multidict from webob.multidict import MultiDict md = MultiDict() md[1] = ‘b‘ md.add(1,‘a‘) print(md.get(1)) #只返回一个值 print(md.getall(1)) # print(md.getone(1)) #要求key的value只能有一个,否则抛KeyError异常 print(md.get(‘c‘)） #不存在返回默认值None #运行结果： a [‘b‘, ‘a‘] None
3.4 webob.dec.wsgify 装饰器
将一个函数变成一个WSGI应用程序
# wsgify
from wsgiref.simple_server import make_server
from webob import Request, Response,dec
def application(environ: dict, start_response):
res = Response("<h1>北京欢迎你</h1>")
#200 OK
#[(‘Content-Type‘, ‘text/html; charset=UTF-8‘), (‘Content-Length‘, ‘0‘)]
return res(environ,start_response) #__call__
@dec.wsgify
def app(request:Request) -> Response:
return Response("<h1>Welcome to BeiJing</h1>")
ip = ‘127.0.0.1‘
port = 9999
# server = make_server(ip, port, application)
server = make_server(ip, port, app)
server.serve_forever()
server.server_close()
#浏览器访问：http://127.0.0.1:9999/index.html?id=5&name=tom,jerry&age=17&age=18,19
#运行结果：
127.0.0.1 - - [26/Dec/2017 20:25:14] "GET /index.html?id=5&name=tom,jerry&age=17&age=18,19 HTTP/1.1" 200 27
127.0.0.1 - - [26/Dec/2017 20:25:14] "GET /favicon.ico HTTP/1.1" 200 27
改进：
from wsgiref.simple_server import make_server
from webob import Request, Response,dec
@dec.wsgify
def app(request:Request) -> Response:
return Response("<h1>Welcome to BeiJing.</h1>")
if __name__ == "__main__":
ip = ‘127.0.0.1‘
port = 9999
server = make_server(ip, port, app)
try:
server.serve_forever()
except KeyBoardInterrupt:
pass
finally:
server.server_close()
总结：
本文简单介绍了WSGI、WSGI HTTP Server、查询字符串的处理、第三方库webob的一些用法。
