如何在C中使用套接字向http/https网站发送GET请求

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>

#define BUFFER_SIZE 4096

int main() {
    // 创建套接字
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd == -1) {
        perror("Failed to create socket");
        exit(1);
    }

    // 解析主机名
    struct hostent *host = gethostbyname("www.example.com");
    if (host == NULL) {
        perror("Failed to resolve hostname");
        exit(1);
    }

    // 设置服务器地址
    struct sockaddr_in server_addr;
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(80);  // HTTP默认端口为80
    server_addr.sin_addr = *((struct in_addr *)host->h_addr);
    memset(&(server_addr.sin_zero), '\0', 8);

    // 连接服务器
    if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {
        perror("Failed to connect to server");
        exit(1);
    }

    // 构造HTTP请求
    char request[BUFFER_SIZE];
    snprintf(request, BUFFER_SIZE, "GET / HTTP/1.1\r\nHost: www.example.com\r\n\r\n");

    // 发送请求
    if (send(sockfd, request, strlen(request), 0) == -1) {
        perror("Failed to send request");
        exit(1);
    }

    // 接收响应并打印
    char response[BUFFER_SIZE];
    memset(response, 0, BUFFER_SIZE);
    while (recv(sockfd, response, BUFFER_SIZE - 1, 0) > 0) {
        printf("%s", response);
        memset(response, 0, BUFFER_SIZE);
    }

    // 关闭套接字
    close(sockfd);

    return 0;
}