Web框架的引入

为什么会有web框架

有了上一篇内容，静态、动态web服务器的实现，已经掌握了客户端请求到服务器处理的机制。在动态资源处理中，根据请求 .py 导入模块应用，然后调用应用入口程序实现动态处理。但是在真实的项目中，肯定有很多应用（.py文件），按照这种处理机制（每个应用中都要写一个入口，设置状态码、headers）不符合架构设计原则，这一部分肯定是可以复用的，所用应用应该公用一个入口，这就引入一个概念web框架。

设计思路

把每个应用中入口 application(env,start_response) 提取到web服务器中，然后在入口中通过路由机制分发到各应用中处理。

代码如下：

- WebFramework.py

`

# coding:utf-8

import time

from MyWebServer import WebServer

HTML_ROOT_DIR = "./static"

class Application(object):

    '''自定义通用的web框架'''

    # 初始化路由信息

    def __init__(self,urls):

        self.urls = urls

    # 匹配路由

    def __call__(self, env, start_response):

        path = env.get("PATH_INFO", "/")

        # /static/index.html

        if path.startswith("/static"):

            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:

            if path == url:

                return handler(env,start_response)

        # 未匹配到

        status = '404 Not Found'

        headers = []

        start_response(status,headers)

        return 'not found'

def showtime(env,start_response):

    status = '200 OK'

    headers = [

        ('Content-Type', 'text/plain')

    ]

    start_response(status, headers)

    return str(time.time())

def sayhello(env,start_response):

    status = '200 OK'

    headers = [

        ('Content-Type','text/plain')

    ]

    start_response(status,headers)

    return 'say hello'

def helloworld(env,start_response):

    status = '200 OK'

    headers =[

        ('Content-Type','text/plain')

    ]

    start_response(status,headers)

    return 'hello world'

if __name__ == '__main__':

    urls = [

        ('/', showtime),

        ('/sayhello',sayhello),

        ('/helloworld',helloworld)

    ]

    app = Application(urls)

    webServer = WebServer(app)

    webServer.bind(8000)

    webServer.start()

`

- MyWebServer.py

`

# coding:utf-8

import socket

import re

import sys

from multiprocessing import Process

HTML_ROOT_DIR = './static'

WSGI_PY = './wsgipy'

class WebServer(object):

    '''

    简单的webserver

    '''

    def __init__(self,application):

        '''application：框架'''

        self.sock_server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

        self.sock_server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

        self.app = application

    def start(self):

        self.sock_server.listen(128)

        while True:

            sock_client, addr = self.sock_server.accept()

            print('[%s,%s]用户已连接......' % addr)

            handle_client_process = Process(target=self.handle_client, args=(sock_client,))

            handle_client_process.start()

            sock_client.close()

    def start_response(self, status, headers):

        """

                 status = "200 OK"

            headers = [

                ("Content-Type", "text/plain")

            ]

            star

                """

        resp_headers = 'HTTP/1.1 ' + status + '\r\n'

        for header in headers:

            resp_headers += '%s: %s\r\n' % header

        self.resp_headers = resp_headers

    def handle_client(self, sock_client):

        '''处理客户端请求'''

        recv_data = sock_client.recv(1024)

        #print('请求数据：', recv_data)

        req_lines = recv_data.splitlines()

        #for line in req_lines:

        #    print(line)

        req_start_line = req_lines[0]

        #print(req_start_line.decode('utf-8'))

        file_name = re.match(r"\w+ +(/[^ ]*) ", req_start_line.decode("utf-8")).group(1)

        method = re.match(r"(\w+) +/[^ ]* ", req_start_line.decode("utf-8")).group(1)

        env = {

            "PATH_INFO": file_name,

            "METHOD": method

        }

        response_body = self.app(env, self.start_response)

        response = self.resp_headers + "\r\n" + response_body

        # 向客户端返回响应数据

        sock_client.send(bytes(response, "utf-8"))

        # 关闭客户端连接

        sock_client.close()

    def bind(self, port):

        self.sock_server.bind(('', port))

def main():

    sys.path.insert(1,WSGI_PY)

    webServer = WebServer()

    webServer.bind(8000)

    webServer.start()

if __name__ == '__main__':

    main()

`

启动

入口实在WebFramework.py 中，直接启动该文件，客户端请求指定路径即可看到效果。但是对于大多框架都是通过命令行启动，我们不可能在程序中这样启动，而且对于webserver来说始终是不变得，变的是web框架，所以改造成命令行启动，代码如下：

- WebFramework.py

`

# coding:utf-8

import time

HTML_ROOT_DIR = "./static"

class Application(object):

    '''自定义通用的web框架'''

    # 初始化路由信息

    def __init__(self,urls):

        self.urls = urls

    # 匹配路由

    def __call__(self, env, start_response):

        path = env.get("PATH_INFO", "/")

        # /static/index.html

        if path.startswith("/static"):

            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:

            if path == url:

                return handler(env,start_response)

        # 未匹配到

        status = '404 Not Found'

        headers = []

        start_response(status,headers)

        return 'not found'

def showtime(env,start_response):

    status = '200 OK'

    headers = [

        ('Content-Type', 'text/plain')

    ]

    start_response(status, headers)

    return str(time.time())

def sayhello(env,start_response):

    status = '200 OK'

    headers = [

        ('Content-Type','text/plain')

    ]

    start_response(status,headers)

    return 'say hello'

def helloworld(env,start_response):

    status = '200 OK'

    headers =[

        ('Content-Type','text/plain')

    ]

    start_response(status,headers)

    return 'hello world'

urls = [

    ('/', showtime),

    ('/sayhello',sayhello),

    ('/helloworld',helloworld)

]

app = Application(urls)

# if __name__ == '__main__':

#     urls = [

#         ('/', showtime),

#         ('/sayhello',sayhello),

#         ('/helloworld',helloworld)

#     ]

#     app = Application(urls)

#

#     webServer = WebServer(app)

#     webServer.bind(8000)

#     webServer.start()

`

- MyWebServer.py

`

# coding:utf-8

import socket

import re

import sys

from multiprocessing import Process

HTML_ROOT_DIR = './static'

WSGI_PY = './wsgipy'

class WebServer(object):

    '''

    简单的webserver

    '''

    def __init__(self,application):

        '''application：框架'''

        self.sock_server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

        self.sock_server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

        self.app = application

    def start(self):

        self.sock_server.listen(128)

        while True:

            sock_client, addr = self.sock_server.accept()

            print('[%s,%s]用户已连接......' % addr)

            handle_client_process = Process(target=self.handle_client, args=(sock_client,))

            handle_client_process.start()

            sock_client.close()

    def start_response(self, status, headers):

        """

                 status = "200 OK"

            headers = [

                ("Content-Type", "text/plain")

            ]

            star

                """

        resp_headers = 'HTTP/1.1 ' + status + '\r\n'

        for header in headers:

            resp_headers += '%s: %s\r\n' % header

        self.resp_headers = resp_headers

    def handle_client(self, sock_client):

        '''处理客户端请求'''

        recv_data = sock_client.recv(1024)

        #print('请求数据：', recv_data)

        req_lines = recv_data.splitlines()

        #for line in req_lines:

        #    print(line)

        req_start_line = req_lines[0]

        #print(req_start_line.decode('utf-8'))

        file_name = re.match(r"\w+ +(/[^ ]*) ", req_start_line.decode("utf-8")).group(1)

        method = re.match(r"(\w+) +/[^ ]* ", req_start_line.decode("utf-8")).group(1)

        env = {

            "PATH_INFO": file_name,

            "METHOD": method

        }

        response_body = self.app(env, self.start_response)

        response = self.resp_headers + "\r\n" + response_body

        # 向客户端返回响应数据

        sock_client.send(bytes(response, "utf-8"))

        # 关闭客户端连接

        sock_client.close()

    def bind(self, port):

        self.sock_server.bind(('', port))

def main():

    sys.path.insert(1,WSGI_PY)

    if len(sys.argv) < 2:

        sys.exit("python MyWebServer.py Module:app")

    module_name, app_name = sys.argv[1].split(':')

    m = __import__(module_name)

    app = getattr(m,app_name)

    webServer = WebServer(app)

    webServer.bind(8000)

    webServer.start()

if __name__ == '__main__':

    main()

`

调用方式

在命令行中，执行如下命令即可启动webserver服务，模块名称：应用框架名，其中这里的app指的是WebFramework.py中Application类的实例，其实也就是应用框架的实例。后续自定义框架的时候，直接调用即可。

`

python MyWebServer.py WebFramework:app

`

代码已上传到github：python 小程序

巴特西

Web框架的引入

为什么会有web框架

设计思路

代码如下：

- WebFramework.py

- MyWebServer.py

启动

- WebFramework.py

- MyWebServer.py

调用方式

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