TCP/IP协议学习(四) 基于C# Socket的Web服务器---静态资源处理

2023-03-19 20:30:18

1. C# Socket通讯

2. HTTP 解析引擎

3. 资源读取和返回

4. 服务器测试和代码下载

　　Web服务器是Web资源的宿主，它需要处理用户端浏览器的请求，并指定对应的Web资源返回给用户，这些资源不仅包括HTML文件，JS脚本，JPG图片等，还包括由软件生成的动态内容。为了满足上述需求，一个完整的Web服务器工作流程:

　　1) 服务器获得浏览器通过TCP/IP连接向服务器发送的http请求数据包。

　　2) HTTP请求经过Web服务器的HTTP解析引擎分析得出请求方法、资源地址等信息，然后开始处理。

　　3) 对于静态请求，则在服务器上查询请求url路径下文件，并返回(如果未找到则返回404 No Found)。

　　4) 涉及动态请求，如CGI， AJAX， ASP等，则根据http方法，采取不同处理。

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" 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　　Web服务器的核心由C# Socket通讯，http解析引擎，静态资源文件查找，动态数据接收和发送4部分组成，本节因为个人编写进度原因主要实现前3个部分(即能够查询静态资源的Web服务器)，动态数据处理因为涉及的处理方式CGI，AJAX，ASP的方法不同，后续完成后在总结相关知识。

1. C# Socket通讯　

　　C# Socket通过对TCP/IP协议进行封装，用于实现满足TCP通讯的API。在B/S架构中，服务器端的处理和C/S连接基本相同，主要工作包含：创建Socket套接字，监听连接，建立连接，获得请求，处理并返回数据，关闭连接等。

　　程序入口函数，采用轮询方式实现对客户端请求的监听。

          //创建监听线程

          Thread Listen_thread = new Thread(socket_listen);

          Listen_thread.IsBackground = false;

          Listen_thread.Start();

　　监听线程，创建Socket套接字，绑定并监听指定端口，等待连接建立，连接建立后，考虑到网页请求高并发的特性，采用另开线程的方式来处理建立的连接，从而实现并发服务器模式。

            Socket server_socket = null;

            //监听的IP地址和端口 作为服务器，绑定的只能是本机Ip地址或者环回地址(不能与系统其它进程端口冲突)

            //如果绑定为本节IP地址，局域网下其它设备可以通过http://host:port来访问当前服务器

            string host = "127.0.0.1";

            int port = ;

            IPAddress ip = IPAddress.Parse(host);

            IPEndPoint ipe = new IPEndPoint(ip, port);

            //新建Socket套接字，绑定在指定的端口并开始监听

            server_socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);

            server_socket.Bind(ipe);

            server_socket.Listen();

            Console.WriteLine("Server Binding at " + host + ":" + port.ToString() +"...");

            Console.WriteLine("Wait for connect....");

            while (true)

            {

                Socket CurrentSocket;

                //三次握手成功，新建一个连接

                CurrentSocket = server_socket.Accept();

                Console.WriteLine("New TCP Socket Create...");

                //单开一个线程用来处理服务器收发, 并发服务器模式

                ParameterizedThreadStart tStart = new ParameterizedThreadStart(socket_process);

                Thread process_thread = new Thread(tStart);

                process_thread.IsBackground = false;

                process_thread.Start(CurrentSocket);

            }

　　连接处理，socket通讯处理主要负责接收连接产生的数据，并将http引擎处理后数据提交给客户端浏览器。

          Socket CurrentSocket = (Socket)obj;

          try

          {

                string recvStr = "";

                byte[] recvBytes = new byte[];

                int length;

                //获得当前Socket连接传输的数据，并转换为ASCII码格式

                length = CurrentSocket.Receive(recvBytes, recvBytes.Length, );

                recvStr = Encoding.ASCII.GetString(recvBytes, , length);

                //http引擎处理，返回获得数据

                byte[] bs =  http_engine(recvStr, length);

                //通过socket发送引擎处理后数据

                CurrentSocket.Send(bs, bs.Length, );

                Console.WriteLine("File Send Finish, Socket Close....\r\n");

                //关闭socket连接

                CurrentSocket.Close();

            }

            catch (Exception exception)

            {

                Console.WriteLine(exception);

                CurrentSocket.Close();

            }

　　C# Socket通讯架构的实现和C/S结构没有什么区别，如果了解过Socket可以轻松实现上述socket通讯架构。不过下面这部分将讲述Web服务器的实现核心--http解析引擎，这也是B/S架构和C/S架构中服务器端最大的区别。

2. http解析引擎

　 Web服务器主要实现对浏览器请求数据包的处理，并返回指定的http资源或者数据，这些都是由http解析引擎实现，在写http解析引擎之前，我们要知晓接收到的数据才能进行后续的处理，这里提供通过WireShark抓取的http请求包:

　　虽然HTTP请求包的内容很多，但因为目前实现的功能较少，所以关注的只有http报文起始行就可以，而首部字段可以直接丢弃不处理，后续如果使用认证机制，如白名单，黑名单过滤，帐号/密码保护，资源权限管理等，首部仍然要处理。

　　对于http报文起始行, 内部以space隔开，并以'\r\n'作为结尾与首部隔开。其中GET：HTTP方法， '/' ：资源路径url， HTTP/1.1:协议版本，参照http权威指南的内容,　　HTTP协议的常见方法有GET, PUT, DELETE, POST, HEAD这5种，本节中的静态服务器主要涉及到GET方法。了解了需要如何解析HTTP请求报文后，我们先定义一个HTTP报文解析结构，用于存储到解析的信息。

        public class HTTPPrase

        {

           //http方法

           public string http_method;

           //http资源

           public string url;

           //http版本号

           public string version;

           //url解析的请求网页类型

           public string type;

        };

　　下面我们就要开始利用C#提供的String方法来截取http报文来实现上述结构体内参数的初始化。

            int pos;

           //根据\r\n截断，获取http报文首部并转换为小写，方便后续处理

           //Get / HTTP/1.1/r/n

           pos = str.IndexOf("\r\n");

           string str_head = str.Substring(, pos);

           str_head = str_head.ToLower();

            //根据' '来截断起始行，并赋值给对应参数

           string[] arr = Regex.Split(str_head, @"\s+");

           HTTPServer.HTTPPrase http_head = new HTTPServer.HTTPPrase();

           http_head.http_method = arr[];      // "Get"

           http_head.url = arr[];              // "/"

           http_head.version = arr[];          // "HTTP/1.1"

            //判断是否有通过ajax要求获得或者提交的动态数据

           http_head.ajax_status = str_head.IndexOf(".ajax") != - ? true : false;

           byte[] bs = http_head.ajax_status == true ? ajax_process(http_head, str) : static_process(http_head, str);

           return bs;

　　下面就可以把数据提交给后端接口，进行处理。因为动态网页处理需要网页端和后端相互的配合，工作量较大，因此本节主要阐述静态网页请求的实现。

3. 资源读取和返回

　　局域网Web请求一般是通过ip+port的模式直接访问服务器端，所以第一个接收到的请求的url为‘/',这时我们需要将它映射到服务端定位的访问主页，目前设置为index.html，对于其它请求，url的值一般是'/xxx/xxx.js"， '/xxx/xxx.jpg"等，而在服务器中读取时我们需要定义绝对地址，所以还要在前面添加资源存储的根地址，目前将程序当前所在文件夹+html作为资源的根地址，而且操作系统存储的数据路径为\xxx\xxx.js，所以对于请求中url数据还要替换为'\\'（为了保证转义符能够转变为路径符，需要用'\\'表示实际的'\')，此外为了后续的http响应报文中返回正确的Content-Type字段，还有截取'.'后字段，来获取请求文件的类型。

              //获得当前程序所在的文件夹

              string url_str = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase;

              if (string.Compare(head.url, "/") == )

              {

                 //对于首个请求127.0.0.1:3000/ 返回index.html

                 url_str += "html\\index.html";

                 head.type = "html";

              }

              else

              {

                 //其它请求 如/spring.js 替换为 ...\html\spring.js便于C#查询文件路径

                 url_str =url_str + "html\\" + head.url.Substring();

                 url_str = url_str.Replace('/', '\\');

                 int pos = url_str.IndexOf('.');

                //获得当前请求的网页类型

                head.type = url_str.Substring(pos + );

              }

　　到此为止，完成了整个http解析的过程，包括http方法， url资源地址获得并转换为windows系统路径，协议版本获得三个部分。对于静态网页请求，后续就比较简单，查询系统路径下资源，通过文件流打开，并以字符流的形式放置在内存中，作为http响应报文的正文部分。

             //以文件流的方式打开指定路径内文件

             using (FileStream fs = new FileStream(url_str, FileMode.Open, FileAccess.Read))

             {

                  //StreamReader temp = new StreamReader(fs, Encoding.Default);

                  int fslen = (int)fs.Length;

                  byte[] fbyte = new byte[fslen];

                  int r = fs.Read(fbyte, , fslen);

                  fs.Close();   

                  //......

            }

文件打开成功后，我们就要生成http响应报文了，http响应报文和请求报文相同，也由三部分构成。

　　状态码:主要为客户端提供一种理解事务处理结果的便捷方式。主要实现的有:

　　HTTP/1.1 200 OK 请求没有问题，实体的主体部分包含请求的资源

HTTP/1.1 400 Bad Request 通知客户端它发送了一个错误的请求

　　HTTP/1.1 401 Unauthorized 与适当的首部一同返回，通知客户端进行相应的认证

HTTP/1.1 404 No Found 说明服务器无法找到请求的URL

　响应首部:为客户端提供额外的关于服务器的消息，本项目中实现比较简单：

　　Content-type:CurrentType\r\n

　　Server:C# Web\r\n

　　Content-Length:CurrentLength\r\n

　　Connection: close

　其中Contenet-type需要根据我们上文获得的type类型来替换，这里阐述常见的替换规则。

Content-Length字段是http响应报文正文的长度，即我们获得资源的总长度(上文中fslen), 最后将状态码，响应首部和正文数据整合在一起通过socket发送到客户端，就实现了静态服务器的全部过程。

                            string HTTP_Current_Head = HTTPServer.HTTP_OK_Head.Replace("CurrentLength", Convert.ToString(fslen));

                            //根据不同url需要返回不同的首部类型 具体对比详见http://tool.oschina.net/commons

                       　　  switch (head.type)

                            {

                                case "jpg":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "application/x-jpg");

                                    break;

                                case "png":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "image/png");

                                    break;

                                case "html":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "text/html");

                                    break;

                                case "gif":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "image/gif");

                                    break;

                                case "js":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "application/x-javascript");

                                    break;

                                case "asp":

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "text/asp");

                                    break;

                                default:

                                    HTTP_Current_Head = HTTP_Current_Head.Replace("CurrentType", "text/html");

                                    break;

                            }

                            send_str = HTTPServer.HTTP_OK_Start + HTTP_Current_Head;

                            byte[] head_byte = new byte[send_str.Length];

                            head_byte = Encoding.UTF8.GetBytes(send_str);

                            //字符串流合并,生成发送文件

                            //之前采用的是byte[]->string, string合并， string->byte[]，这种方法读取图片乱码

                            //因此修改为，string合并， string->byte[], byte[]合并方式，读取图片成功

                            byte[] send_byte = new byte[send_str.Length + fbyte.Length];

                            Buffer.BlockCopy(head_byte, , send_byte, , head_byte.Length);

                            Buffer.BlockCopy(fbyte, , send_byte, head_byte.Length * sizeof(byte), fbyte.Length);

                            Console.WriteLine("File Send....");

                            return send_byte;

4. 服务器测试和代码下载

　　到现在为止，一个简单的静态web服务器就实现了，将希望访问的资源文件放入当前程序文件夹/html/下，并将首页定义为index.html, 点开服务器程序，浏览器中输入http://127.0.0.1:3000, 就可以查看返回的网页。

具体程序参考:Web服务器下载

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