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@1405010312 2016-12-02T04:13:39.000000Z 字数 3553 阅读 495

web服务器

web服务器

1.http协议

  • 其响应客户端的请求后就立马断开连接,也就是说服务端不会维持客户端状态.所以其又称为"无状态的Stateless协议"由于这个特性,web编程通常用Cookie和Session技术.

  • 请求消息结构:其由消息行,消息头,消息体构成.请求行含有请求方式信息(GET和POST),请求行只有一行.消息头包含发送请求的浏览器信息,用户认证信息等附加信息.消息体与消息头中有一行空行用来区分消息头和消息体.

2.实验原理

  • 获取请求消息,并相应提取请求方式和文件的绝对路径,通过绝对路径打开文件,然后传送给浏览器.

3.实验代码

  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4. #include <winsock2.h>
  5. #include <process.h>
  7. #define BUF_SIZE  2048
  8. #define BUF_SMALL  100
  10. unsigned  WINAPI RequestHandler(void* arg);
  11. char* ContentType(char* file);
  12. void SendData(SOCKET sock, char* ct, char* fileName);
  13. void SendErrorMSG(SOCKET sock);
  14. void ErrorHandling(char *message);
  16. int main(int argc, char *argv[])
  17. {
  18.     WSADATA wsaData;
  19.     SOCKET hServSock, hClntSock;
  20.     SOCKADDR_IN servAdr, clntAdr;
  22.     HANDLE hThread;
  23.     DWORD dwThreadID;
  24.     int clntAdrSize;
  26.     if(argc!=2) {
  27.         printf("Usage : %s <port>\n", argv[0]);
  28.         exit(1);
  29.     }
  31.     if(WSAStartup(MAKEWORD(2, 2), &wsaData)!=0)
  32.         ErrorHandling("WSAStartup() error!");
  34.     hServSock=socket(PF_INET, SOCK_STREAM, 0);   
  35.     memset(&servAdr, 0, sizeof(servAdr));
  36.     servAdr.sin_family=AF_INET;
  37.     servAdr.sin_addr.s_addr=htonl(INADDR_ANY);
  38.     servAdr.sin_port=htons(atoi(argv[1]));
  40.     if(bind(hServSock, (SOCKADDR*) &servAdr, sizeof(servAdr))==SOCKET_ERROR)
  41.         ErrorHandling("bind() error");
  42.     if(listen(hServSock, 5)==SOCKET_ERROR)
  43.         ErrorHandling("listen() error");
  46.     while(1)
  47.     {
  48.         clntAdrSize=sizeof(clntAdr);
  49.         hClntSock=accept(hServSock, (SOCKADDR*)&clntAdr, &clntAdrSize);
  50.         printf("Connection Request : %s:%d\n", 
  51.             inet_ntoa(clntAdr.sin_addr), ntohs(clntAdr.sin_port));
  52.         hThread=(HANDLE)_beginthreadex(
  53.             NULL, 0, RequestHandler, (void*)hClntSock, 0, (unsigned *)&dwThreadID);
  54.     }
  55.     closesocket(hServSock);
  56.     WSACleanup();
  57.     return 0;
  58. }
  60. unsigned WINAPI RequestHandler(void *arg)
  61. {
  62.     SOCKET hClntSock=(SOCKET)arg;
  63.     char buf[BUF_SIZE];
  64.     char method[BUF_SMALL];
  65.     char ct[BUF_SMALL];
  66.     char fileName[BUF_SMALL];
  68.     recv(hClntSock, buf, BUF_SIZE, 0);
  69.     if(strstr(buf, "HTTP/")==NULL) 
  70.     {
  71.         SendErrorMSG(hClntSock);
  72.         closesocket(hClntSock);
  73.         return 1;
  74.     }
  76.     strcpy(method, strtok(buf, "/"));
  77.     if(strcmp(method, "GET "))
  78.         SendErrorMSG(hClntSock);
  80.     strcpy(fileName, strtok(NULL, " "));  
  81.     strcpy(ct, ContentType(fileName));      
  82.     SendData(hClntSock, ct, fileName);    
  83.     return 0;
  84. }
  86. void SendData(SOCKET sock, char* ct, char* fileName) 
  87. {   
  88.     char protocol[]="HTTP/1.0 200 OK\r\n";
  89.     char servName[]="Server:simple web server\r\n";
  90.     char cntLen[]="Content-length:2048\r\n";
  91.     char cntType[BUF_SMALL];
  92.     char buf[BUF_SIZE];
  93.     FILE* sendFile;
  95.     sprintf(cntType, "Content-type:%s\r\n\r\n", ct);
  96.     if((sendFile=fopen(fileName, "r"))==NULL)
  97.     {
  98.         SendErrorMSG(sock);
  99.         return;
  100.     }
  102.     send(sock, protocol, strlen(protocol), 0);
  103.     send(sock, servName, strlen(servName), 0);
  104.     send(sock, cntLen, strlen(cntLen), 0); 
  105.     send(sock, cntType, strlen(cntType), 0);
  107.     while(fgets(buf, BUF_SIZE, sendFile)!=NULL) 
  108.         send(sock, buf, strlen(buf), 0);
  110.     closesocket(sock);  
  111. }
  113. void SendErrorMSG(SOCKET sock)  
  114. {   
  115.     char protocol[]="HTTP/1.0 400 Bad Request\r\n";
  116.     char servName[]="Server:simple web server\r\n";
  117.     char cntLen[]="Content-length:2048\r\n";
  118.     char cntType[]="Content-type:text/html\r\n\r\n";
  119.     char content[]="<html><head><title>NETWORK</title></head>"
  120.            "<body><font size=+5><br>发生错误!"
  121.            "</font></body></html>";
  123.     send(sock, protocol, strlen(protocol), 0);
  124.     send(sock, servName, strlen(servName), 0);
  125.     send(sock, cntLen, strlen(cntLen), 0); 
  126.     send(sock, cntType, strlen(cntType), 0);
  127.     send(sock, content, strlen(content), 0);
  128.     closesocket(sock);
  129. }
  131. char* ContentType(char* file)   
  132. {
  133.     char extension[BUF_SMALL];
  134.     char fileName[BUF_SMALL];
  135.     strcpy(fileName, file);
  136.     strtok(fileName, ".");
  137.     strcpy(extension, strtok(NULL, "."));
  138.     if(!strcmp(extension, "html")||!strcmp(extension, "htm")) 
  139.         return "text/html";
  140.     else
  141.         return "text/plain";
  142. }
  144. void ErrorHandling(char* message)
  145. {
  146.     fputs(message, stderr);
  147.     fputc('\n', stderr);
  148.     exit(1);
  149. }

4.实验结果:
No
Yes

5.实验总结
感觉这次学到了很多东西,主要是知道了HTTP协议,并懂得了如何初步处理它.在实验过程中也遇到了各种各样的问题,比如消息行的处理等.这次没有写图形界面了,感觉好难写不出来.还有就是由于HTTP是无状态的协议,所以最好是来个while循环发送消息,不然很容易看不到内容.

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