黑马程序员---搭建静态web服务器

偏执的太偏执、 2022-11-26 04:56 189阅读 0赞

一：返回固定页面的静态web服务器：  
1：初始化web服务器：创建套接字—> 设置端口复用—>绑定本地端口—>设置监听模式  
2：循环接受用户：accpet —>接受用户数据---->recv  
3：读取服务器固定页面信息  
4：构造响应报文  
5：向客户端发送指定页面信息  
6：关闭套接字

二：返回指定页面的静态web服务器  
思路：要想返回指定页面就需要，分析请求报文：请求报文格式：请求行（请求方式 请求地址 HTTP协议版本）  
所以我只需要使用空格将字符串分割一下就好了。分割的第二部分就是请求地址。

#得到请求后分割字符串，设置分割两次
            request_list = recv_data.split(" ",maxsplit=2)
            
    		# 取出资源路径部分
            request_addr = request_list[1]
    
    
            # 3:读取服务器指定文件
            
    		#将指定路径加进去
            with open("static"+ request_addr,"rb") as file:
                send_data = file.read()

三：增加默认页面：  
思路：如果我输入127.0.0.1:7788/ 会报错，因为服务器找不到这个路径。所以需要设置默认路径。  
解决方式就是判断截取到的信息是不是“/” 如果是替换成"/index.html"

request_addr = request_list[1]
    
            if request_addr == "/":
                request_addr = "/index.html"

四：解决找不到报错问题：  
问题：如果服务器中没有这个文件，那么在`with open("static"+ request_addr,"rb") as file: send_data = file.read()`这个地方就会报错。导致服务器直接挂掉了。  
解决办法：给这段代码加`try ... except...else...finally`进行捕获，并且让他出错后返回到错误页面。  
核心代码：

try:
    
                with open("static"+ request_addr,"rb") as file:
                    send_data = file.read()
            except Exception as e:
    
                # 4:构造相应报文
                response_line = "HTTP:/1.1 200 ok\r\n"
                response_head = "NBNB:ASD\r\n"
                with open("static/error.html", "rb") as file:
                    send_data = file.read()
                response_data = (response_line + response_head+"\r\n").encode("utf-8")+send_data
    
                #5: 发送给客户端
                new_socket.send(response_data)
            else:
                # 4:构造相应报文
                response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
                response_head = "NBNB:ASD\r\n"
    
                response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                # 5: 发送给客户端
                new_socket.send(response_data)
    
            finally:
                # 6关闭套接字
                new_socket.close()

import socket
    
    def main():
    
        # 1:初始化服务器
        tcp_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        tcp_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,True)
        tcp_socket.bind(("",7788))
        tcp_socket.listen(128)
    
        # 2:循环接收用户
        while True:
    
            new_socket, client_msg = tcp_socket.accept()
            print("客户端%s发来请求",client_msg)
    
            recv_data = new_socket.recv(1024).decode("utf-8")
            print(recv_data)
    
            request_list = recv_data.split(" ",maxsplit=2)
    
            request_addr = request_list[1]
    
    
            if request_addr == "/":
                request_addr = "/index.html"
    
            # 3:读取服务器指定文件
    
            try:
    
                with open("static"+ request_addr,"rb") as file:
                    send_data = file.read()
            except Exception as e:
    
                # 4:构造相应报文
                response_line = "HTTP:/1.1 200 ok\r\n"
                response_head = "NBNB:ASD\r\n"
                with open("static/error.html", "rb") as file:
                    send_data = file.read()
                response_data = (response_line + response_head+"\r\n").encode("utf-8")+send_data
    
                #5: 发送给客户端
                new_socket.send(response_data)
            else:
                # 4:构造相应报文
                response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
                response_head = "NBNB:ASD\r\n"
    
                response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                # 5: 发送给客户端
                new_socket.send(response_data)
    
            finally:
                # 6关闭套接字
                new_socket.close()
    
    
    if __name__ == '__main__':
        main()

五：解决客户端异常关闭问题：  
问题：如果客户端突然关闭，会导致`recv_data = new_socket.recv(1024).decode("utf-8")`这个地方解阻塞，此时服务器会收到来自客户端的空数据，此时`request_addr = request_list[1]`这里就会拿不到数据，导致下标越界。

解决方案：  
判断是不是空数据，如果是关闭套接字，然后直接退出。

核心代码：

recv_data = new_socket.recv(1024).decode("utf-8")
    
            if len(recv_data) == 0:
                new_socket.close()
                continue

import socket
    
    def main():
    
        # 1:初始化服务器
        tcp_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        tcp_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,True)
        tcp_socket.bind(("",7788))
        tcp_socket.listen(128)
    
        # 2:循环接收用户
        while True:
    
            new_socket, client_msg = tcp_socket.accept()
            print("客户端%s发来请求",client_msg)
    
            recv_data = new_socket.recv(1024).decode("utf-8")
    
            if len(recv_data) == 0:
            
            	new_socket.close()
                continue
    
                
            print(recv_data)
    
            request_list = recv_data.split(" ",maxsplit=2)
    
            request_addr = request_list[1]
    
    
            if request_addr == "/":
                request_addr = "/index.html"
    
            # 3:读取服务器指定文件
    
            try:
    
                with open("static"+ request_addr,"rb") as file:
                    send_data = file.read()
            except Exception as e:
    
                # 4:构造相应报文
                response_line = "HTTP:/1.1 200 ok\r\n"
                response_head = "NBNB:ASD\r\n"
                with open("static/error.html", "rb") as file:
                    send_data = file.read()
                response_data = (response_line + response_head+"\r\n").encode("utf-8")+send_data
    
                #5: 发送给客户端
                new_socket.send(response_data)
            else:
                # 4:构造相应报文
                response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
                response_head = "NBNB:ASD\r\n"
    
                response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                # 5: 发送给客户端
                new_socket.send(response_data)
    
            finally:
                # 6关闭套接字
                new_socket.close()
    
    
    if __name__ == '__main__':
        main()

六：多任务版本  
问题：现在是服务器只有服务完第一个客户端，并且关闭new\_socket才能为下一个客户端服务。  
解决办法：让服务客户端的另外创建一个线程，单独服务。这样主线程还可以继续让客户端连接。  
并且，为了保证服务器断掉，必成功，就要保证子线程守护主线程。  
核心代码：

while True:
    
            new_socket, client_msg = tcp_socket.accept()
            print("客户端%s发来请求",client_msg)
    
            t1 = threading.Thread(target=service_client, args=(new_socket,))
    
            t1.daemon = True
    
            t1.start()

import socket
    
    import threading
    
    
    def service_client(new_socket):
        recv_data = new_socket.recv(1024).decode("utf-8")
    
        if len(recv_data) == 0:
            new_socket.close()
            return
    
        print(recv_data)
    
        request_list = recv_data.split(" ", maxsplit=2)
    
        request_addr = request_list[1]
    
        if request_addr == "/":
            request_addr = "/index.html"
    
        # 3:读取服务器指定文件
    
        try:
    
            with open("static" + request_addr, "rb") as file:
                send_data = file.read()
        except Exception as e:
    
            # 4:构造相应报文
            response_line = "HTTP:/1.1 200 ok\r\n"
            response_head = "NBNB:ASD\r\n"
            with open("static/error.html", "rb") as file:
                send_data = file.read()
            response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
            # 5: 发送给客户端
            new_socket.send(response_data)
        else:
            # 4:构造相应报文
            response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
            response_head = "NBNB:ASD\r\n"
    
            response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
            # 5: 发送给客户端
            new_socket.send(response_data)
    
        finally:
            # 6关闭套接字
            new_socket.close()
    
    
    def main():
    
        # 1:初始化服务器
        tcp_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        tcp_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,True)
        tcp_socket.bind(("",7788))
        tcp_socket.listen(128)
    
        # 2:循环接收用户
        while True:
    
            new_socket, client_msg = tcp_socket.accept()
            print("客户端%s发来请求",client_msg)
    
            t1 = threading.Thread(target=service_client, args=(new_socket,))
    
            t1.daemon = True
    
            t1.start()
    
    
    if __name__ == '__main__':
        main()

七：改版成面向对象的格式----搭建静态web服务器

思路：主程序可以定义一个搭建服务器的对象，然后调用它的start() 方法就可以了。  
搭建服务器的类：1: init初始化方法 2：start方法 3子线程处理的方法。

import socket
    
    import threading
    
    
    class  Create_Web_Service(object):
    
            def __init__(self):
                # 1:初始化服务器
                self.tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                self.tcp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
                self.tcp_socket.bind(("", 7788))
                self.tcp_socket.listen(128)
    
    
            def start(self):
                while True:
                    new_socket, client_msg = self.tcp_socket.accept()
                    print("客户端%s发来请求", client_msg)
    
                    t1 = threading.Thread(target=self.handle_client, args=(new_socket,))
    
                    t1.daemon = True
    
                    t1.start()
    
            @staticmethod
            def handle_client(new_socket):
                recv_data = new_socket.recv(1024).decode("utf-8")
    
                if len(recv_data) == 0:
                    new_socket.close()
                    return
    
                print(recv_data)
    
                request_list = recv_data.split(" ", maxsplit=2)
    
                request_addr = request_list[1]
    
                if request_addr == "/":
                    request_addr = "/index.html"
    
                # 3:读取服务器指定文件
    
                try:
    
                    with open("static" + request_addr, "rb") as file:
                        send_data = file.read()
                except Exception as e:
    
                    # 4:构造相应报文
                    response_line = "HTTP:/1.1 200 ok\r\n"
                    response_head = "NBNB:ASD\r\n"
                    with open("static/error.html", "rb") as file:
                        send_data = file.read()
                    response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                    # 5: 发送给客户端
                    new_socket.send(response_data)
                else:
                    # 4:构造相应报文
                    response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
                    response_head = "NBNB:ASD\r\n"
    
                    response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                    # 5: 发送给客户端
                    new_socket.send(response_data)
    
                finally:
                    # 6关闭套接字
                    new_socket.close()
    
    
    def main():
    
        s = Create_Web_Service()
    
        s.start()
    
    if __name__ == '__main__':
            main()

八：静态Web服务器-命令行启动动态绑定端口号：

因为命令行启动需要两个参数，所以要判断输入的参数是不是两位，此外还要判断端口是不是整数，如果都符合则将命令行输入的端口替换原来的7788.

1：获取执行python程序的终端命令行参数
    
     sys.argv:
    
    2：判断参数的类型，设置端口号必须是整型
    
     if not sys.argv[1].isdigit():
         print("启动命令如下: python3 xxx.py 9090")
         return
     port = int(sys.argv[1])
     
    3：给Web服务器类的初始化方法添加一个端口号参数，用于绑定端口号
    
     def __init__(self, port):
         self.tcp_server_socket.bind((“”, port))

import socket
    
    import threading
    import sys
    
    
    class Create_Web_Service(object):
    
        def __init__(self, port):
            # 1:初始化服务器
            self.tcp_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.tcp_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
            self.tcp_socket.bind(("", port))
            self.tcp_socket.listen(128)
    
        def start(self):
            while True:
                new_socket, client_msg = self.tcp_socket.accept()
                print("客户端%s发来请求", client_msg)
    
                t1 = threading.Thread(target=self.handle_client, args=(new_socket,))
    
                t1.daemon = True
    
                t1.start()
    
        @staticmethod
        def handle_client(new_socket):
            recv_data = new_socket.recv(1024).decode("utf-8")
    
            if len(recv_data) == 0:
                new_socket.close()
                return
    
            print(recv_data)
    
            request_list = recv_data.split(" ", maxsplit=2)
    
            request_addr = request_list[1]
    
            if request_addr == "/":
                request_addr = "/index.html"
    
            # 3:读取服务器指定文件
    
            try:
    
                with open("static" + request_addr, "rb") as file:
                    send_data = file.read()
            except Exception as e:
    
                # 4:构造相应报文
                print(e)
                response_line = "HTTP:/1.1 200 ok\r\n"
                response_head = "NBNB:ASD\r\n"
                with open("static/error.html", "rb") as file:
                    send_data = file.read()
                response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                # 5: 发送给客户端
                new_socket.send(response_data)
            else:
                # 4:构造相应报文
                response_line = "HTTP:/1.1 404 NOT FOUND\r\n"
                response_head = "NBNB:ASD\r\n"
    
                response_data = (response_line + response_head + "\r\n").encode("utf-8") + send_data
    
                # 5: 发送给客户端
                new_socket.send(response_data)
    
            finally:
                # 6关闭套接字
                new_socket.close()
    
    
    def main():
    
        print(sys.argv)
        if len(sys.argv) != 2:
            print("请输入输入两个单词:一个地址,一个端口.")
            return
    
        if not sys.argv[1].isdigit():
            print("请输入输入两个单词:一个地址,一个端口.")
            return
    
        port = int(sys.argv[1])
    
        s = Create_Web_Service(port)
    
        s.start()
    
    if __name__ == '__main__':
        main()