Web伺服器程式設計

晖_IL發表於2024-06-13
Web伺服器程式設計

Web程式設計

Web程式設計.c

伺服器應答格式：

伺服器接收到瀏覽器的資料之後，需要判斷GET/後面跟的網頁是否存在，如果存在則請求成功，傳送指定的指令，併傳送檔案內容給瀏覽器，如果不存在，則傳送請求失敗的指令

請求成功：

"HTTP/1.1 200 OK\r\n "   \
"Content-Type: text/html\r\n"  \
"\r\n";

請求失敗

"HTTP/1.1 400 OK\r\n "   \"
"Content-Type: text/html\r\n"   \
"\r\n"   \
"<HTML><BOOY>File not found</BODY></HTML>"

案例

/*
#    Web程式設計
#    https://www.cnblogs.com/kencszqh
#
#    File Name:  Web_servicer.c
#    Created  :  2024-06-13
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/wait.h>
#include <signal.h>
#include <errno.h>

#define PATH "./xxxwork/"
#define N 128
#define ERR_LOG(errmsg)                                     \
    do                                                      \
    {                                                       \
        perror(errmsg);                                     \
        exit(1);                                            \
    } while (0)

void *pthread_func(void *arg)
{
    int acceptfd = *(int *)arg;
    char buf[N] = {0};
    char head[] = "HTTP/1.1 200 OK\r\n"
                  " Content-Type: text/html\r\n"
                  "\r\n ";
    char err[] = "HTTP/1.1 404 Not Found\r\n"
                 "Content-Type: text/html\r\n"
                 "\r\n"
                 "<html><body><h1>404 Not Found</h1></body></html>";

    // 接收瀏覽器透過HTTP協議傳送的資料包
    if (recv(acceptfd, buf, N, 0) < 0)
    {
        ERR_LOG("recv");
    }
    printf("%s\n", buf);
    // GET /index.html HTTP/1.1
    char filename[N] = {0};
    sscanf(buf, "GET /%s", filename); // sscanf()函式與空格結束，所以直接可以獲取到檔名

    // 擷取檔名後判段一下是否是HTTP/1.1
    if (strncmp(filename, "HTTP/1.1", strlen("http/1.1")) == 0)
    {
        strcpy(filename, "index.html");
    }
    printf("filename:%s\n", filename);

    char path[N] = "PATH";

    // 透過解析出來的網頁檔名，查詢本地中有沒有這個檔案
    int fd;
    if ((fd = open(path, O_RDONLY)) < 0)
    {
        // 如果檔案不存在，則發生不存在對應的指令
        if (errno == ENOENT)
        {
            if (send(acceptfd, err, strlen(err), 0) < 0)
            {
                ERR_LOG("send");
            }
            close(acceptfd);
            pthread_exit(NULL);
        }
        else
        {
            ERR_LOG("open");
        }
    }

    // 如果檔案存在，則傳送檔案內容
    if (send(acceptfd, head, strlen(head), 0) < 0)
    {
        ERR_LOG("send");
    }

    // 讀取檔案內容，併傳送給瀏覽器
    ssize_t n;
    char text[1024] = {0};
    while ((n = read(fd, text, sizeof(text))) > 0)
    {
        if (send(acceptfd, text, n, 0) < 0)
        {
            ERR_LOG("send");
        }
    }
}

int main(int argc, char const *argv[])
{
    if (argc != 3)
    {
        fprintf(stderr, "Usage:%s [ip] [port]\n", argv[0]);
        exit(1);
    }

    int sockfd, acceptfd;
    struct sockaddr_in serveraddr, clientaddr;
    socklen_t addrlen = sizeof(serveraddr);

    // 1.建立套接字
    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        ERR_LOG("socket");
    }

    // 2.繫結
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_port = htons(atoi(argv[2]));
    serveraddr.sin_addr.s_addr = inet_addr(argv[1]);

    if (bind(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
    {
        ERR_LOG("bind");
    }

    // 3.監聽
    if (listen(sockfd, 5) < 0)
    {
        ERR_LOG("listen");
    }

    // 4.接受客戶端連線
    while (1)
    {
        if ((acceptfd = accept(sockfd, (struct sockaddr *)&clientaddr, &addrlen)) < 0)
        {
            ERR_LOG("accept");
        }

        printf("client ip:%s,port:%d\n", inet_ntoa(clientaddr.sin_addr), ntohs(clientaddr.sin_port));

        pthread_t thread;
        if (pthread_create(&thread, NULL, pthread_func, &acceptfd) != 0)
        {
            ERR_LOG("pthread_create");
        }

        pthread_detach(thread);
    }

    return 0;
}

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