jchat_server:    main.o process.o sql.o
    gcc -o jchat_server main.o process.o sql.o -L/usr/lib/mysql -lmysqlclient
    rm -f *.o *.gch *~
main.o:            main.c process.h sql.h
    gcc -c main.c process.h sql.h -I/usr/include/mysql
process.o:        process.h process.h
    gcc -c process.c process.h -I/usr/include/mysql
sql.o:            sql.c sql.h
    gcc -c sql.c sql.h -I/usr/include/mysql

clean:
    rm -f *.o *.gch *~ jchat_server

/*server/main.c*/

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>

#include "process.h"
#include "sql.h"

#define MAXLINE 4096
#define LISTENQ 1024
#define PORT 12345

int listenfd;
pid_t pid_online_time, pid_conn;

/*
 * init server create socket
 */
void server_init()
{
    listenfd = socket(AF_INET, SOCK_STREAM, );

    struct sockaddr_in servaddr;
    memset(&servaddr, , sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(PORT);

    bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr));

    listen(listenfd, LISTENQ);
}

int main(int argc, char *argv[])
{
    server_init();

    pid_online_time = fork();
    ) {
        refresh_online_time();
    }

    ) {
        struct sockaddr_in cliaddr;
        int clilen = sizeof(cliaddr);

        int connfd = accept(listenfd, (struct sockaddr *)&cliaddr, &clilen);

        ) {
            close(listenfd);
            process(connfd);
        }
        else {
            pid_t pid = getpid();
            //printf("fork process pid = %d\n", pid);
        }

        close(connfd);
    }

    exit();
}

/*server/process.c*/

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <my_global.h>
#include <my_sys.h>
#include <mysql.h>

#include "process.h"
#include "sql.h"

#define MAXLINE 4096

char sendbuff[MAXLINE], recvbuff[MAXLINE];
int recv_len;

/*
 * all users' online time - 1 every second
 */
void refresh_online_time()
{
    MYSQL *conn = sql_init();

    ) {
        mysql_query(conn, "update jchat.user set online_time=online_time-1 \
                    ;");
        //printf("refresh online time -1\n");
        sleep();
    }
}

/*
 * regist new user
 * fail when user exists already
 */
void regist(int sockfd)
{
    MYSQL *conn = sql_init();

    int i, j, k, l;
    i = ;j = ;
    while (recvbuff[j] != ':') ++j;
    k = j + ;
    ], passwd[];
    for (l=i; l<j; ++l) {
        user[l-i] = recvbuff[l];
    }
    user[j-i] = '\0';
    for (l=k; l<recv_len; ++l) {
        passwd[l-k] = recvbuff[l];
    }
    user[recv_len-k] = '\0';

    ];
    sprintf(query, \
            "select * from jchat.user where user='%s';", \
            user);
    mysql_query(conn, query);

    MYSQL_RES *res = mysql_use_result(conn);
    MYSQL_ROW row = mysql_fetch_row(res);
    if (row != NULL) { // exist user
        sendbuff[] = ] = '\0';
    }
    else {
        sendbuff[] = ] = '\0';
        sprintf(query, \
                "insert into jchat.user values('%s','%s',0);", \
                user, passwd);
        mysql_query(conn, query);
    }
    mysql_free_result(res);

    write(sockfd, sendbuff, strlen(sendbuff));
    //printf("sendbuff> '%s'\n", sendbuff);

    sql_exit(conn);

    printf("regist user=%s passwd=%s\n", user, passwd);
}

/*
 * login a user
 * fail if user and password not match
 */
void login(int sockfd)
{
    MYSQL *conn = sql_init();

    int i, j, k, l;
    i = ;j = ;
    while (recvbuff[j] != ':') ++j;
    k = j + ;
    ], passwd[];
    for (l=i; l<j; ++l) {
        user[l-i] = recvbuff[l];
    }
    user[j-i] = '\0';
    for (l=k; l<recv_len; ++l) {
        passwd[l-k] = recvbuff[l];
    }
    user[recv_len-k] = '\0';

    ];
    sprintf(query, \
            "select * from jchat.user where user='%s' and passwd='%s';", \
            user, passwd);
    mysql_query(conn, query);

    MYSQL_RES *res = mysql_use_result(conn);
    MYSQL_ROW row = mysql_fetch_row(res);
    if (row != NULL) { // user and passwd correct
        sendbuff[] = ] = '\0';
        sprintf(query, \
                "update jchat.user set online_time=7 \
                where user='%s';", user);
        mysql_query(conn, query);
    }
    else {
        sendbuff[] = ] = '\0';
    }
    mysql_free_result(res);

    write(sockfd, sendbuff, strlen(sendbuff));
    //printf("sendbuff> '%s'\n", sendbuff);

    sql_exit(conn);

    printf("login user=%s passwd=%s\n", user, passwd);
}

/*
 * get user online notice and update online time to 12
 */
void user_at()
{
    MYSQL *conn = sql_init();

    int i;
    ];
    ; i<recv_len; ++i) {
        user[i-] = recvbuff[i];
    }
    user[recv_len-] = '\0';

    ];
    sprintf(query, \
            "update jchat.user set online_time=12 where user='%s';", \
            user);
    mysql_query(conn, query);

    sql_exit(conn);

    //printf("%s is online\n", user);
}

/*
 * return a user's unread message
 * and delete the message in mysql
 */
void get_mesg(int sockfd)
{
    MYSQL *conn = sql_init();

    int i;
    ];
    ; i<recv_len; ++i) {
        user[i-] = recvbuff[i];
    }
    user[recv_len-] = '\0';

    ];
    sprintf(query, \
            "select * from jchat.user where \
            user='%s';", user);
    mysql_query(conn, query);

    MYSQL_RES *res = mysql_use_result(conn);
    MYSQL_ROW row = mysql_fetch_row(res);
    if (row != NULL) { // user exist
        mysql_free_result(res);
        sprintf(query, \
                "select * from jchat.mesg where recvuser='%s';", \
                user);
        mysql_query(conn, query);

        ], recvuser[], text[];

        res = mysql_use_result(conn);
        sendbuff[] = '\0';
        ;
        while ((row = mysql_fetch_row(res)) != NULL) {
            hasMesg = ;
            int row_num = mysql_num_fields(res);
            strcpy(senduser, row[]);
            strcpy(recvuser, row[]);
            strcpy(text,     row[]);

            strcat(sendbuff, senduser);
            strcat(sendbuff, ":"     );
            strcat(sendbuff, text    );
            strcat(sendbuff, ";"     );
        }

        if (!hasMesg) {
            strcpy(sendbuff, ";");
        }

        mysql_free_result(res);

        sprintf(query, \
                "delete from jchat.mesg where recvuser='%s';", \
                user);
        mysql_query(conn, query);

        write(sockfd, sendbuff, strlen(sendbuff));
        //printf("get_mesg sendbuff> '%s'\n", sendbuff);
    }

    sql_exit(conn);

    //printf("%s get message from server\n", user);
}

/*
 * one user send message to another user
 * store to mysql
 */
void send_mesg()
{
    MYSQL *conn = sql_init();

    int i, j, k, x;
    i = ;j = ;
    while (recvbuff[j] != ':') ++j;
    ++j;
    k = j + ;
    while (recvbuff[k] != ':') ++k;
    ++k;
    //printf("i=%d, j=%d, k=%d\n",i,j,k);

    ], recvuser[], text[];
    ; x<j--i; ++x) {
        senduser[x] = recvbuff[x+i];
    }
    senduser[j--i] = '\0';
    ; x<k--j; ++x) {
        recvuser[x] = recvbuff[x+j];
    }
    recvuser[k--j] = '\0';
    ; x<recv_len-k; ++x) {
        text[x] = recvbuff[x+k];
    }
    text[recv_len-k] = '\0';
    //printf("senduser = '%s'\nrecvuser = '%s'\n", senduser, recvuser);

    ;

    ];
    sprintf(query, \
            "select * from jchat.user where user='%s';", \
            senduser);
    mysql_query(conn, query);

    MYSQL_RES *res = mysql_use_result(conn);
    MYSQL_ROW row = mysql_fetch_row(res);
    if (row == NULL) { // send user not exist
        user_exist = ;
    }
    mysql_free_result(res);

    sprintf(query, \
            "select * from jchat.user where user='%s';", \
            recvuser);
    mysql_query(conn, query);

    res = mysql_use_result(conn);
    row = mysql_fetch_row(res);
    if (row == NULL) { // recv user not exist
        user_exist = ;
    }
    mysql_free_result(res);

    if (user_exist) {
        sprintf(query, \
                "insert into jchat.mesg values('%s','%s','%s');", \
                senduser, recvuser, text);
        mysql_query(conn, query);
    }

    sql_exit(conn);

    printf("%s send message to %s\n", senduser, recvuser);
}

/*
 * return current online users
 */
void online_user(int sockfd)
{
    MYSQL *conn = sql_init();

    mysql_query(conn, "select user from jchat.user where online_time>0;");
    sendbuff[] = '\0';
    MYSQL_RES *res = mysql_use_result(conn);
    MYSQL_ROW row;
    ;
    while ((row = mysql_fetch_row(res)) != NULL) {
        hasOnline = ;
        strcat(sendbuff, row[]);
        strcat(sendbuff, ";"   );
       }

    if (!hasOnline) {
        strcpy(sendbuff, ";");
    }

    mysql_free_result(res);

    write(sockfd, sendbuff, strlen(sendbuff));
    //printf("online_user sendbuff> '%s'\n", sendbuff);

    sql_exit(conn);
}

/*
 * user quit
 * update online time to 0
 */
void quit()
{
    MYSQL *conn = sql_init();

    int i;
    ];
    ; i<recv_len; ++i) {
        user[i-] = recvbuff[i];
    }
    user[recv_len-] = '\0';

    ];
    sprintf(query, \
            "update jchat.user set online_time=0 where user='%s';", \
            user);
    mysql_query(conn, query);

    printf("%s quit\n", user);

    sql_exit(conn);
    exit(); // exit this process
}

void process(int sockfd)
{
    ) {
        recvbuff[recv_len] = '\0';
        //printf("process recvbuff> '%s'\n", recvbuff);
        ]) {
            case 'r': // regist
                regist(sockfd);
                break;
            case 'l': // login
                login(sockfd);
                break;
            case 'a': // online notice
                user_at();
                break;
            case 'g': // get message
                get_mesg(sockfd);
                break;
            case 's': // send message
                send_mesg();
                break;
            case 'o': // online user check
                online_user(sockfd);
                break;
            case 'q': // quit
                quit();
                break;
        }
    }
}

/*server/process.h*/

#ifndef PROCESS_H
#define PROCESS_H

#include <my_global.h>
#include <my_sys.h>
#include <mysql.h>

/*
 * refresh online user's online time every minute
 * seemed as offline if online time decrease to 0
 */
void refresh_online_time();

/*
 * process different command from client
 */
void process(int sockfd);

#endif // PROCESS_H

/*server/sql.h*/

#include <my_global.h>
#include <my_sys.h>
#include <mysql.h>

#include "sql.h"

static char *host_name = "localhost";
static char *user_name = "your mysql user"; // 这里要更换为自己mysql用户的用户名与密码
static char *passwd = "your mysql password";
;
static char *socket_name = NULL;
static char *db_name = "jchat";
;

MYSQL *sql_init()
{
    MYSQL *conn;

    MY_INIT("jchat_server");

    ,NULL,NULL)) {
        fprintf(stderr, "mysql_library_init() failed\n");
        return NULL;
    }

    conn = mysql_init(NULL);
    if (conn == NULL) {
        fprintf(stderr, "mysql_init() failed\n");
        return NULL;
    }

    if (mysql_real_connect(conn,host_name,user_name,passwd,
            db_name,port_num,socket_name,flags) == NULL) {
        fprintf(stderr, "mysql_real_connect() failed\n");
        mysql_close(conn);
        return NULL;
    }

    return conn;
}

void sql_exit(MYSQL *conn)
{
    mysql_close(conn);
    mysql_library_end();
}

/*server/sql.h*/

#ifndef SQL_H
#define SQL_H

#include <my_global.h>
#include <my_sys.h>
#include <mysql.h>

/*
 * link to mysql
 * return 1 if succeed, 0 if fail
 */
MYSQL *sql_init();

void sql_exit(MYSQL *conn);

#endif // SQL_H