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。
wsgirefPython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:environ、start_response
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
res_str = b'\n'# 函数实现def application(environ, start_response):return [res_str]# 类实现class Application:def __init__(self, environ, start_response):passdef __iter__(self):yield res_str# 类实现class Application:def __call__(self, environ, start_response):retur [res_str]
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 1from wsgiref.simple_server import make_serverdef demo_app(environ, start_response): #copy自simple_server模块from io import StringIOstdout = 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 = 9999server = 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)
通过这个函数可以启动一个用于简单访问的WSGI参考服务器,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/ 15:01:13] "GET / HTTP/1.1" 200 2128127.0.0.1 - - [26/Dec/ 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 2from wsgiref.simple_server import make_serverdef 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 =9999server = make_server(ip,port,application)server.serve_forever()server.server_close()#运行结果:127.0.0.1 - - [26/Dec/ 15:38:55] "GET / HTTP/1.1" 200 24127.0.0.1 - - [26/Dec/ 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_stringimport cgifrom wsgiref.simple_server import make_serverdef application(environ:dict,start_response):qstr = environ.get("QUERY_STRING")print(qstr)# ?id=5&name=ihoney&age=18,19print(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 =9999server = 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/ 15:51:17] "GET /?id=5&name=ihoney&age=18,19 HTTP/1.1" 200 24id=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_stringfrom urllib import parsefrom wsgiref.simple_server import make_serverdef application(environ:dict,start_response):qstr = environ.get("QUERY_STRING")print(qstr)# ?id=5&name=ihoney&age=18,19print(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 =9999server = 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/ 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。
webob.request module:
req.method: 请求方法
req.GET: 返回一个类字典对象,GET请求方式提交的查询字符串的二元组格式。
req.POST: 也返回一个类字典对象,POST请求正文的查询字符串。一般是表单提交
req.params: 一个类字典对象,包括GET和POST的所有查询字符串。
req.body: POST提交的请求正文的内容
req.cookies: 字典格式的所有cookie
req.headers: 包含所有请求头的字典,不区分大小写
web.response module:
response.status: 响应码加描述信息,如"200 OK"
response.status_code: 响应码,只有 "200"
response.headerlist: 所有响应头的列表,如"[('Content-Type', 'text/html')]"
response.app_iter: 一个可迭代对象(如列表和生成器),用于产生响应的内容
response.content_type: 响应内容的类型,如"text/html","text/plain"
response.charset: 字符集编码类型
response.set_cookie(name=None, value='', max_age=None, path='/', domain=None, secure=False, httponly=False, comment=None, overwrite=False): 为客户端设置一个cookie,max_age控制cookie的有效时长,以秒为单位
response.delete_cookie(key, path='/', domain=None): 从客户端删除一个cookie
response.cache_expires(seconds=0): 设置这个响应的缓存时间,单位为秒,如果seconds为0表示这个响应不缓存
response(environ, start_response): 返回对象是一个WSGI应用程序的响应
3.1 webob.Request
#简单web 5,使用第三方库webob解析from wsgiref.simple_server import make_serverfrom webob import Request, Responsedef 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 = 9999server = 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.htmlGET([('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=18,19127.0.0.1 - - [26/Dec/ 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_serverfrom webob import Request, Responsedef 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 = 9999server = 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/ 18:08:03] "GET /index.html?id=5&name=tom,jerry&age=17&age=18,19 HTTP/1.1" 200 24
3.3 MultiDict
MultiDict允许一个key存好几个值。
Request.GET、Request.POST 都是MultiDict字典
# multidictfrom webob.multidict import MultiDictmd = 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
官方文档:/projects/webob/en/stable/api/dec.html
功能:将一个函数变成一个WSGI应用程序
使用举例:
from webob.dec import wsgify@wsgifydef myfunc(req):return webob.Response('hey there')
wsgi装饰器装饰的函数应该具有一个参数,这个参数是webob.Request类型,是对字典environ的对象化后的实例。返回值必须是一个webob.Respnose类型,所以在函数中应该创建一个webob.Response类型的实例。
# wsgifyfrom wsgiref.simple_server import make_serverfrom webob import Request, Response,decdef 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.wsgifydef 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/ 20:25:14] "GET /index.html?id=5&name=tom,jerry&age=17&age=18,19 HTTP/1.1" 200 27127.0.0.1 - - [26/Dec/ 20:25:14] "GET /favicon.ico HTTP/1.1" 200 27
改进:
from wsgiref.simple_server import make_serverfrom webob import Request, Response,dec@dec.wsgifydef app(request:Request) -> Response:return Response("<h1>Welcome to BeiJing.</h1>")if __name__ == "__main__":ip = '127.0.0.1'port = 9999server = make_server(ip, port, app)try:server.serve_forever()except KeyBoardInterrupt:passfinally:server.server_close()
3.5 webob.Response SourceCode
def __call__(self, environ, start_response):"""WSGI application interface"""if self.conditional_response:return self.conditional_response_app(environ, start_response)headerlist = self._abs_headerlist(environ)start_response(self.status, headerlist)if environ['REQUEST_METHOD'] == 'HEAD':# Special case here...return EmptyResponse(self._app_iter)return self._app_iter
Chrome插件Postman POST 提交:
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。