Question

    if ( isset($_POST['update']) ){
    $db=mysqli_connect("localhost","****","****","****");
    $lasttime = isset($_POST['timestamp']) ? $_POST['timestamp'] : 0;
    while (1){
        sleep(1);
        clearstatcache();
        $mresult = mysqli_query($db,"SELECT * FROM tblchat WHERE msg_datetime > $lasttime");
        if (!empty($mresult)){ break; }
    }
    $msgs = array();
    while ($row = mysqli_fetch_object( $mresult )) { $msgs[] = $row; }
    mysqli_free_result($mresult);
    $response = array();
    $response['msgs'] = $msgs;
    echo json_encode($response);
    flush();
    mysqli_close($db);
    exit();
    }

代码是与客户端进行长轮询连接的服务器。如果请求更新，则while循环将检查在使用更新请求发送的时间戳之后收到的任何新消息。如果找到，它将结果放入一个数组并将其回送给客户端。结果输出类似于[msgs:[{msg_from:"",msg_to:"",msg:"",msg_datetime:""},{msg_from:"",msg_to:"",msg:"",msg_datetime:""}]]

代码第一次工作正常并发送所有最近的消息，但是它再次发送一个空数组的消息。请指导我。

Answer 1

用 mysqli_num_rows

解决了这个问题

if (mysqli_num_rows($mresult)){ $msgs = array(); while ($row = mysqli_fetch_object( $mresult )) { $msgs[] = $row; } mysqli_free_result($mresult); break; }
if (mysqli_num_rows($wresult)){ $writers = array(); while ($row = mysqli_fetch_object( $wresult )) { $writers[] = $row; } mysqli_free_result($wresult); break; }

感谢大家的帮助！

MYSQLi SELECT获取对象

1 个答案: