python_web（三）一个简单web后端框架

#简单的web后端框架
#coding: utf-8

import socket


def log(*args, **kwargs):
    print('log', *args, **kwargs)
#日志输出记录函数


def route_index():
    header = 'HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n'
    body = '<h1>hello world</h1><img src="/doge.gif">'
    #应将上式换做自己的图片路径
    r = header + '\r\n' + body
    return r.encode(encoding='utf-8')
#制作返回给客户端的内容，返回为bytes格式


def page(name):
    with open(name, encoding='utf-8') as f:
        return f.read()
#打开文件路径为name的html文件，返回值为文件编码后内容


def route_msg():
    header = 'HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n'
    body = page('html_basic.html')
    # 应将上式换做自己的html文件展现
    r = header + '\r\n' + body
    return r.encode(encoding='utf-8')
#制作返回给客户端的内容(其中含有html文件)，返回为bytes格式


def route_image():
    with open('doge.gif', 'rb') as f:
        header = b'HTTP/1.1 200 OK\r\nContent-Type: image/gif\r\n'
        img = header + b'\r\n' + f.read()
        return img
#图片的处理函数，读取图片并生成响应返回(读取图片形式为rb，bytes)


def error(code = 404):
    e = {
        404: b'HTTP/1.1 404 NOT FOUND\r\n\r\n<h1>NOT FOUND</h1>',
    }
    return e.get(code, b'')
#404错误返回函数


def response_for_path(path):
    r = {
        '/': route_index,
        '/doge.gif': route_image,
        '/msg': route_msg,
    }
    response = r.get(path, error)
    return response()
#路由函数，不同地址，出现不同的结果，取不到地址，返回错误函数


def run(host='', port = 3000):
    with socket.socket() as s:
        s.bind((host, port))
        while True:
            s.listen(5)
            connection, address = s.accept()
            request = connection.recv(1024)
            log('raw, ', request)
            request = request.decode('utf-8')
            log('ip and request, {}\n{}'.format(address, request))
            try:
                path = request.split()[1]
                log('path, ', path)
                response = response_for_path(path)
                connection.sendall(response)
            except Exception as e:
                log('error', e)
                #异常时返回异常信息
            connection.close()
#服务器运行函数，运行，连接


def main():
    config = dict(
        host = '',
        port = 3000,
    )
    run(**config)
    #生成配置并运行程序


if __name__ == '__main__':
    main()