C++如何监听http请求

转载
shixin_0125 2022-08-20 01:28:13
下面有个例子，基于 Windows 的，编译完，运行 : WebSrv 7070 即可。在程序的目录中放一个 index.html 文件。

/*************************************************************************
 * 
 * Copyright (c) 2002-2005 by Zhang Huiyong All Rights Reserved
 *
 * FILENAME:  WebSrv.c
 *
 * PURPOSE :  HTTP 服务器程序, 向客户端提供请求的文件内容.
 *  
 * AUTHOR  :  张会勇
 * 
 * BOOK    :  <<WinSock网络编程经络>>
 * 
 **************************************************************************/

#include <stdio.h>
#include <winsock2.h>

#pragma comment(lib, "ws2_32.lib")  /* WinSock使用的库函数 */

/* 定义常量 */
#define HTTP_DEF_PORT        80     /* 连接的缺省端口 */
#define HTTP_BUF_SIZE      1024     /* 缓冲区的大小 */
#define HTTP_FILENAME_LEN   256     /* 文件名长度 */

/* 定义文件类型对应的 Content-Type */
struct doc_type
{
    char *suffix; /* 文件后缀 */
    char *type;   /* Content-Type */
};

struct doc_type file_type[] = 
{
    {"html",    "text/html"  },
    {"gif",     "image/gif"  },
    {"jpeg",    "image/jpeg" },
    { NULL,      NULL        }
};

char *http_res_hdr_tmpl = "HTTP/1.1 200 OK\r\nServer: Huiyong's Server <0.1>\r\n"
    "Accept-Ranges: bytes\r\nContent-Length: %d\r\nConnection: close\r\n"
    "Content-Type: %s\r\n\r\n";


/**************************************************************************
 *
 * 函数功能: 根据文件后缀查找对应的 Content-Type.
 *
 * 参数说明: [IN] suffix, 文件名后缀;
 *
 * 返 回 值: 成功返回文件对应的 Content-Type, 失败返回 NULL.
 *
 **************************************************************************/
char *http_get_type_by_suffix(const char *suffix)
{
    struct doc_type *type;

    for (type = file_type; type->suffix; type++)
    {
        if (strcmp(type->suffix, suffix) == 0)
            return type->type;
    }

    return NULL;
}

/**************************************************************************
 *
 * 函数功能: 解析请求行, 得到文件名及其后缀. 请求行格式:
 *           [GET http://www.baidu.com:8080/index.html HTTP/1.1]
 *
 * 参数说明: [IN]  buf, 字符串指针数组;
 *           [IN]  buflen, buf 的长度;
 *           [OUT] file_name, 文件名;
 *           [OUT] suffix, 文件名后缀;
 *
 * 返 回 值: void.
 *
 **************************************************************************/
void http_parse_request_cmd(char *buf, int buflen, char *file_name, char *suffix)
{
    int length = 0;
    char *begin, *end, *bias;

    /* 查找 URL 的开始位置 */
    begin = strchr(buf, ' ');
    begin += 1;
        
    /* 查找 URL 的结束位置 */
    end = strchr(begin, ' ');
    *end = 0;

    bias = strrchr(begin, '/');
    length = end - bias;

    /* 找到文件名的开始位置 */
    if ((*bias == '/') || (*bias == '\\'))
    {
        bias++;
        length--;
    }

    /* 得到文件名 */
    if (length > 0)
    {
        memcpy(file_name, bias, length);
        file_name[length] = 0;

        begin = strchr(file_name, '.');
        if (begin)
            strcpy(suffix, begin + 1);
    }
}


/**************************************************************************
 *
 * 函数功能: 向客户端发送 HTTP 响应.
 *
 * 参数说明: [IN]  buf, 字符串指针数组;
 *           [IN]  buf_len, buf 的长度;
 *
 * 返 回 值: 成功返回非0, 失败返回0.
 *
 **************************************************************************/
int http_send_response(SOCKET soc, char *buf, int buf_len)
{
    int read_len, file_len, hdr_len, send_len;
    char *type;
    char read_buf[HTTP_BUF_SIZE];
    char http_header[HTTP_BUF_SIZE];
    char file_name[HTTP_FILENAME_LEN] = "index.html", suffix[16] = "html";
    FILE *res_file;

    /* 得到文件名和后缀 */
    http_parse_request_cmd(buf, buf_len, file_name, suffix);

    res_file = fopen(file_name, "rb+"); /* 用二进制格式打开文件 */
    if (res_file == NULL)
    {
        printf("[Web] The file [%s] is not existed\n", file_name);
        return 0;
    }

    fseek(res_file, 0, SEEK_END);
    file_len = ftell(res_file);
    fseek(res_file, 0, SEEK_SET);
    
    type = http_get_type_by_suffix(suffix); /* 文件对应的 Content-Type */
    if (type == NULL)
    {
        printf("[Web] There is not the related content type\n");
        return 0;
    }

    /* 构造 HTTP 首部，并发送 */
    hdr_len = sprintf(http_header, http_res_hdr_tmpl, file_len, type);
    send_len = send(soc, http_header, hdr_len, 0);

    if (send_len == SOCKET_ERROR)
    {
        fclose(res_file);
        printf("[Web] Fail to send, error = %d\n", WSAGetLastError());
        return 0;
    }

    do /* 发送文件, HTTP 的消息体 */
    {
        read_len = fread(read_buf, sizeof(char), HTTP_BUF_SIZE, res_file);

        if (read_len > 0)
        {
            send_len = send(soc, read_buf, read_len, 0);
            file_len -= read_len;
        }
    } while ((read_len > 0) && (file_len > 0));

    fclose(res_file);
    
    return 1;
}


int main(int argc, char **argv)
{
    WSADATA wsa_data;
    SOCKET  srv_soc = 0, acpt_soc;  /* socket 句柄 */ 
    struct sockaddr_in serv_addr;   /* 服务器地址  */
    struct sockaddr_in from_addr;   /* 客户端地址  */
    char recv_buf[HTTP_BUF_SIZE];
    unsigned short port = HTTP_DEF_PORT;
    unsigned long from_len = sizeof(from_addr);
    int result = 0, recv_len;

    if (argc == 2) /* 端口号 */
        port = atoi(argv[1]);

    WSAStartup(MAKEWORD(2,0), &wsa_data); /* 初始化 WinSock 资源 */
    
    srv_soc = socket(AF_INET, SOCK_STREAM, 0); /* 创建 socket */
    if (srv_soc == INVALID_SOCKET)
    {
        printf("[Web] socket() Fails, error = %d\n", WSAGetLastError());
        return -1; 
    }
    
    /* 服务器地址 */
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(port);
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    result = bind(srv_soc, (struct sockaddr *) &serv_addr, sizeof(serv_addr));
    if (result == SOCKET_ERROR) /* 绑定失败 */
    {
        closesocket(srv_soc);
        printf("[Web] Fail to bind, error = %d\n", WSAGetLastError());
        return -1; 
    }

    result = listen(srv_soc, SOMAXCONN);
    printf("[Web] The server is running ... ...\n");

    while (1)
    {
        acpt_soc = accept(srv_soc, (struct sockaddr *) &from_addr, &from_len);
        if (acpt_soc == INVALID_SOCKET) /* 接受失败 */
        {
            printf("[Web] Fail to accept, error = %d\n", WSAGetLastError());
            break; 
        }

        printf("[Web] Accepted address:[%s], port:[%d]\n", 
            inet_ntoa(from_addr.sin_addr), ntohs(from_addr.sin_port));

        recv_len = recv(acpt_soc, recv_buf, HTTP_BUF_SIZE, 0);
        if (recv_len == SOCKET_ERROR) /* 接收失败 */
        {
            closesocket(acpt_soc);
            printf("[Web] Fail to recv, error = %d\n", WSAGetLastError());
            break; 
        }

        recv_buf[recv_len] = 0;

        /* 向客户端发送响应数据 */
        result = http_send_response(acpt_soc, recv_buf, recv_len);
        closesocket(acpt_soc);
    }
    
    closesocket(srv_soc);
    WSACleanup();
    printf("[Web] The server is stopped.\n");

    return 0;
}