【05】Python搭建简单服务器

　　Python动态服务器网页（需要使用WSGI接口），基本实现步骤如下：  
　　　　1.等待客户端的链接，服务器会收到一个http协议的请求数据报  
　　　　2.利用正则表达式对这个请求数据报进行解析（请求方式、提取出文件的环境）
　　　　3.提取出文件的环境之后，利用截断取片的方法将文件名转化为模块名称
　　　　4.使用m = __import__(),就可以得到返回值为m的模块
　　　　5.创建一个env字典：其中包含的是请求方式及文件环境等各种的键值对
　　　　6.创建一个新的动态脚本，其中定义了application这个函数，必须包含env和start_response的参数（也是服务器里的调用方法）
　　　　7.在这个动态脚本中定义状态码status和响应头headers（注意是字典形式，如Content-Type）
　　　　8.然后再调用start_response(status,headers)，但是要注意，这个函数在服务器被定义
　　　　9.在动态脚本中编写动态执行程序
　　　　10.m.appliction的返回值就是回应数据包的body，它的数据头在start_response被整合
　　　　11.将数据头与数据body拼接起来，然后发送给客户端，就可显示动态网页 

MyWebServer
# coding:utf-8
import socket
import re
import sys

from multiprocessing import Process
from MyWebFramework import Application

# 设置静态文件根目录
HTML_ROOT_DIR = "./html"
WSGI_PYTHON_DIR = "./wsgipython"

class HTTPServer(object):
    """"""
    def __init__(self, application):
        """构造函数， application指的是框架的app"""
        self.server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        self.app = application

    def start(self):
        self.server_socket.listen(128)
        while True:
            client_socket, client_address = self.server_socket.accept()
            #print("[%s,%s]用户连接上了" % (client_address[0],client_address[1]))
            print("[%s, %s]用户连接上了" % client_address)
            handle_client_process = Process(target=self.handle_client, args=(client_socket,))
            handle_client_process.start()
            client_socket.close()

    def start_response(self, status, headers):
        """
         status = "200 OK"
    headers = [
        ("Content-Type", "text/plain")
    ]
    star 
        """
        response_headers = "HTTP/1.1 " + status + "
"
        for header in headers:
            response_headers += "%s: %s
" % header

        self.response_headers = response_headers

    def handle_client(self, client_socket):
        """处理客户端请求"""
        # 获取客户端请求数据
        request_data = client_socket.recv(1024)
        print("request data:", request_data)
        request_lines = request_data.splitlines()
        for line in request_lines:
            print(line)

        # 解析请求报文
        # 'GET / HTTP/1.1'
        request_start_line = request_lines[0]
        # 提取用户请求的文件名
        print("*" * 10)
        print(request_start_line.decode("utf-8"))
        file_name = re.match(r"w+ +(/[^ ]*) ", request_start_line.decode("utf-8")).group(1)
        method = re.match(r"(w+) +/[^ ]* ", request_start_line.decode("utf-8")).group(1)

        env = {
            "PATH_INFO": file_name,
            "METHOD": method
        }
        response_body = self.app(env, self.start_response)
        response = self.response_headers + "
" + response_body

        # 向客户端返回响应数据
        client_socket.send(bytes(response, "utf-8"))
        # 关闭客户端连接
        client_socket.close()

    def bind(self, port):
        self.server_socket.bind(("", port))

def main():
    sys.path.insert(1, WSGI_PYTHON_DIR)
    if len(sys.argv) < 2:
        sys.exit("python MyWebServer.py Module:app")
    # python MyWebServer.py  MyWebFrameWork:app
    module_name, app_name = sys.argv[1].split(":")
    # module_name = "MyWebFrameWork"
    # app_name = "app"
    m = __import__(module_name)
    app = getattr(m, app_name)
    http_server = HTTPServer(app)
    # http_server.set_port
    http_server.bind(8000)
    http_server.start()

if __name__ == "__main__":
    main()

MyWebFrameWork
# coding:utf-8
import time
# from MyWebServer import HTTPServer

# 设置静态文件根目录
HTML_ROOT_DIR = "./html"

class Application(object):
    """框架的核心部分，也就是框架的主题程序，框架是通用的"""
    def __init__(self, urls):
        # 设置路由信息
        self.urls = urls

    def __call__(self, env, start_response):
        path = env.get("PATH_INFO", "/")
        # /static/index.html
        if path.startswith("/static"):
            # 要访问静态文件
            file_name = path[7:]
            # 打开文件，读取内容
            try:
                file = open(HTML_ROOT_DIR + file_name, "rb")
            except IOError:
                # 代表未找到路由信息，404错误
                status = "404 Not Found"
                headers = []
                start_response(status, headers)
                return "not found"
            else:
                file_data = file.read()
                file.close()

                status = "200 OK"
                headers = []
                start_response(status, headers)
                return file_data.decode("utf-8")

        for url, handler in self.urls:
            #("/ctime", show_ctime)
            if path == url:
                return handler(env, start_response)

        # 代表未找到路由信息，404错误
        status = "404 Not Found"
        headers = []
        start_response(status, headers)
        return "not found"

def show_ctime(env, start_response):
    status = "200 OK"
    headers = [
        ("Content-Type", "text/plain")
    ]
    start_response(status, headers)
    return time.ctime()

def say_hello(env, start_response):
    status = "200 OK"
    headers = [
        ("Content-Type", "text/plain")
    ]
    start_response(status, headers)
    return "hello itcast"

def say_haha(env, start_response):
    status = "200 OK"
    headers = [
        ("Content-Type", "text/plain")
    ]
    start_response(status, headers)
    return "hello haha"

urls = [
            ("/", show_ctime),
            ("/ctime", show_ctime),
            ("/sayhello", say_hello),
            ("/sayhaha", say_haha),
        ]
app = Application(urls)
# if __name__ == "__main__":
#     urls = [
#             ("/", show_ctime),
#             ("/ctime", show_ctime),
#             ("/sayhello", say_hello),
#             ("/sayhaha", say_haha),
#         ]
#     app = Application(urls)
#     http_server = HTTPServer(app)
#     http_server.bind(8000)
#     http_server.start()