Python的Web框架中Tornado以异步非阻塞而闻名。本篇将使用200行代码完成一个微型异步非阻塞Web框架:Snow。
一、源码
本文基于非阻塞的Socket以及IO多路复用从而实现异步非阻塞的Web框架,其中便是众多异步非阻塞Web框架内部原理。
复制代码#!/usr/bin/env python# -*- coding:utf-8 -*-import reimport socketimport selectimport timeclass HttpResponse(object): ???""" ???封装响应信息 ???""" ???def __init__(self, content=‘‘): ???????self.content = content ???????self.headers = {} ???????self.cookies = {} ???def response(self): ???????return bytes(self.content, encoding=‘utf-8‘)class HttpNotFound(HttpResponse): ???""" ???404时的错误提示 ???""" ???def __init__(self): ???????super(HttpNotFound, self).__init__(‘404 Not Found‘)class HttpRequest(object): ???""" ???用户封装用户请求信息 ???""" ???def __init__(self, conn): ???????self.conn = conn ???????self.header_bytes = bytes() ???????self.header_dict = {} ???????self.body_bytes = bytes() ???????self.method = "" ???????self.url = "" ???????self.protocol = "" ???????self.initialize() ???????self.initialize_headers() ???def initialize(self): ???????header_flag = False ???????while True: ???????????try: ???????????????received = self.conn.recv(8096) ???????????except Exception as e: ???????????????received = None ???????????if not received: ???????????????break ???????????if header_flag: ???????????????self.body_bytes += received ???????????????continue ???????????temp = received.split(b‘\r\n\r\n‘, 1) ???????????if len(temp) == 1: ???????????????self.header_bytes += temp ???????????else: ???????????????h, b = temp ???????????????self.header_bytes += h ???????????????self.body_bytes += b ???????????????header_flag = True ???@property ???def header_str(self): ???????return str(self.header_bytes, encoding=‘utf-8‘) ???def initialize_headers(self): ???????headers = self.header_str.split(‘\r\n‘) ???????first_line = headers[0].split(‘ ‘) ???????if len(first_line) == 3: ???????????self.method, self.url, self.protocol = headers[0].split(‘ ‘) ???????????for line in headers: ???????????????kv = line.split(‘:‘) ???????????????if len(kv) == 2: ???????????????????k, v = kv ???????????????????self.header_dict[k] = vclass Future(object): ???""" ???异步非阻塞模式时封装回调函数以及是否准备就绪 ???""" ???def __init__(self, callback): ???????self.callback = callback ???????self._ready = False ???????self.value = None ???def set_result(self, value=None): ???????self.value = value ???????self._ready = True ???@property ???def ready(self): ???????return self._readyclass TimeoutFuture(Future): ???""" ???异步非阻塞超时 ???""" ???def __init__(self, timeout): ???????super(TimeoutFuture, self).__init__(callback=None) ???????self.timeout = timeout ???????self.start_time = time.time() ???@property ???def ready(self): ???????current_time = time.time() ???????if current_time > self.start_time + self.timeout: ???????????self._ready = True ???????return self._readyclass Snow(object): ???""" ???微型Web框架类 ???""" ???def __init__(self, routes): ???????self.routes = routes ???????self.inputs = set() ???????self.request = None ???????self.async_request_handler = {} ???def run(self, host=‘localhost‘, port=9999): ???????""" ???????事件循环 ???????:param host: ???????:param port: ???????:return: ???????""" ???????sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) ???????sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) ???????sock.bind((host, port,)) ???????sock.setblocking(False) ???????sock.listen(128) ???????sock.setblocking(0) ???????self.inputs.add(sock) ???????try: ???????????while True: ???????????????readable_list, writeable_list, error_list = select.select(self.inputs, [], self.inputs,0.005) ???????????????for conn in readable_list: ???????????????????if sock == conn: ???????????????????????client, address = conn.accept() ???????????????????????client.setblocking(False) ???????????????????????self.inputs.add(client) ???????????????????else: ???????????????????????gen = self.process(conn) ???????????????????????if isinstance(gen, HttpResponse): ???????????????????????????conn.sendall(gen.response()) ???????????????????????????self.inputs.remove(conn) ???????????????????????????conn.close() ???????????????????????else: ???????????????????????????yielded = next(gen) ???????????????????????????self.async_request_handler[conn] = yielded ???????????????self.polling_callback() ???????except Exception as e: ???????????pass ???????finally: ???????????sock.close() ???def polling_callback(self): ???????""" ???????遍历触发异步非阻塞的回调函数 ???????:return: ???????""" ???????for conn in list(self.async_request_handler.keys()): ???????????yielded = self.async_request_handler[conn] ???????????if not yielded.ready: ???????????????continue ???????????if yielded.callback: ???????????????ret = yielded.callback(self.request, yielded) ???????????????conn.sendall(ret.response()) ???????????self.inputs.remove(conn) ???????????del self.async_request_handler[conn] ???????????conn.close() ???def process(self, conn): ???????""" ???????处理路由系统以及执行函数 ???????:param conn: ???????:return: ???????""" ???????self.request = HttpRequest(conn) ???????func = None ???????for route in self.routes: ???????????if re.match(route[0], self.request.url): ???????????????func = route[1] ???????????????break ???????if not func: ???????????return HttpNotFound() ???????else: ???????????return func(self.request)复制代码
二、使用
1. 基本使用
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | from snow import Snow from snow import HttpResponse def index(request): return HttpResponse( ‘OK‘ ) routes = [ (r ‘/index/‘ , index), ] app = Snow(routes) app.run(port = 8012 ) |
2.异步非阻塞:超时
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | from snow import Snow from snow import HttpResponse from snow import TimeoutFuture request_list = [] def async(request): obj = TimeoutFuture( 5 ) yield obj def home(request): return HttpResponse( ‘home‘ ) routes = [ (r ‘/home/‘ , home), (r ‘/async/‘ , async), ] app = Snow(routes) app.run(port = 8012 ) |
3.异步非阻塞:等待
基于等待模式可以完成自定制操作
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 | from snow import Snow from snow import HttpResponse from snow import Future request_list = [] def callback(request, future): return HttpResponse(future.value) def req(request): obj = Future(callback = callback) request_list.append(obj) yield obj def stop(request): obj = request_list[ 0 ] del request_list[ 0 ] obj.set_result( ‘done‘ ) return HttpResponse( ‘stop‘ ) routes = [ (r ‘/req/‘ , req), (r ‘/stop/‘ , stop), ] app = Snow(routes) app.run(port = 8012 ) |
200行自定义异步非阻塞Web框架
原文地址:http://www.cnblogs.com/xuaijun/p/7524478.html