#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
 
#define SERV_PORT 9003
 
char *str_join(char *str1, char *str2);
 
char *html_response(char *res, char *buf);
 
int main(void) {
    int lfd, cfd;
    struct sockaddr_in serv_addr, clin_addr;
    socklen_t clin_len;
    char buf[1024], web_result[1024];
    int len;
    FILE *cin;
 
    if ((lfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        perror("create socket failed");
        exit(1);
    }
 
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(SERV_PORT);
 
    if (bind(lfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) == -1) {
        perror("bind error");
        exit(1);
    }
 
    if (listen(lfd, 128) == -1) {
        perror("listen error");
        exit(1);
    }
 
    signal(SIGCLD, SIG_IGN);
 
    while (1) {
        clin_len = sizeof(clin_addr);
        if ((cfd = accept(lfd, (struct sockaddr *) &clin_addr, &clin_len)) == -1) {
            perror("接收错误\n");
            continue;
        }
 
        cin = fdopen(cfd, "r");
        setbuf(cin, (char *) 0);
        fgets(buf, 1024, cin); //读取第一行
        printf("\n%s", buf);
 
        //============================ cgi 环境变量设置演示 ============================
 
        // 例如 "GET /cgi-bin/user?id=1 HTTP/1.1";
 
        char *delim = " ";
        char *p;
        char *method, *filename, *query_string;
        char *query_string_pre = "QUERY_STRING=";
 
        method = strtok(buf, delim);         // GET
        p = strtok(NULL, delim);             // /user?id=1 
        filename = strtok(p, "?");           // /user
 
        if (strcmp(filename, "/favicon.ico") == 0) {
            continue;
        }
 
        query_string = strtok(NULL, "?");    // id=1
        putenv(str_join(query_string_pre, query_string));
 
        //============================ cgi 环境变量设置演示 ============================
 
        int pid = fork();
 
        if (pid > 0) {
            close(cfd);
        }
        else if (pid == 0) {
            close(lfd);
            FILE *stream = popen(str_join(".", filename), "r");
            fread(buf, sizeof(char), sizeof(buf), stream);
            html_response(web_result, buf);
            write(cfd, web_result, sizeof(web_result));
            pclose(stream);
            close(cfd);
            exit(0);
        }
        else {
            perror("fork error");
            exit(1);
        }
    }
 
    close(lfd);
 
    return 0;
}
 
char *str_join(char *str1, char *str2) {
    char *result = malloc(strlen(str1) + strlen(str2) + 1);
    if (result == NULL) exit(1);
    strcpy(result, str1);
    strcat(result, str2);
 
    return result;
}
 
char *html_response(char *res, char *buf) {
    char *html_response_template = "HTTP/1.1 200 OK\r\nContent-Type:text/html\r\nContent-Length: %d\r\nServer: mengkang\r\n\r\n%s";
 
    sprintf(res, html_response_template, strlen(buf), buf);
 
    return res;
}

#include <stdio.h>
#include <stdlib.h>
 
// 通过获取的 id 查询用户的信息
int main(void) {
 
    //============================ 模拟数据库 ============================
    typedef struct {
        int id;
        char *username;
        int age;
    } user;
 
    user users[] = {
            {},
            {
                    1,
                    "taoshihan",
                    10
            }
    };
    //============================ 模拟数据库 ============================
 
 
    char *query_string;
    int id;
 
    query_string = getenv("QUERY_STRING");
 
    if (query_string == NULL) {
        printf("没有输入数据");
    } else if (sscanf(query_string, "id=%d", &id) != 1) {
        printf("没有输入id");
    } else {
        printf("用户信息查询<br>学号: %d<br>姓名: %s<br>年龄: %d", id, users[id].username, users[id].age);
    }
 
    return 0;
}