每 1 秒选择最后插入的行

Question

I have 2 files:
1. chat.php : contain chat messages.
2. loadSingle.php : grab last new message every 1 second.
When I get the last message it was always return and get the last one. I want to get the last message without duplicate every time.

chat.php :

function loadlastmsg(){
var fromIdl = "<?php echo $chat_from_id;?>";
$.ajax({
    type:'POST',
    url:'loadSingle.php',     
    data:{fromIdl: fromIdl,},
    cache: false,
    beforeSend:function(data){

    },
    success: function(data)  
    {
        $('#mainmsgs').append(data);
    }  
});

}

setInterval(function(){
    loadlastmsg();
}, 1000);


</script>
<a href="javascript: loadlastmsg()">Load Last Message</a>

loadSingle.php :

<?php
if(isset($_POST["fromIdl"], $_POST["fromIdl"]))
{


    $chat_from_ids = $_POST["fromIdl"];


      require_once 'config/config.php';
      mysqli_set_charset($conn,"utf8mb4");

      $chinbox = array();
      $result=$conn->query("SELECT * FROM chat WHERE id = (SELECT MAX(id) FROM chat WHERE to_id=$userId AND from_id=$chat_from_ids OR to_id=$chat_from_ids AND from_id=$userId) ORDER BY chat.send_date DESC LIMIT 1");
      while ($chinbxsx = mysqli_fetch_assoc($result)) { 
        $chinbox[] = $chinbxsx;
        $from_id =  $chinbxsx['from_id'];
        $subject =  $chinbxsx['subject'];
        $message =  $chinbxsx['message'];
        $get_date = $chinbxsx['send_date'];
        $senddate = date_create($chinbxsx['send_date']);
        $senddate = date_format($senddate, 'Y/m/d H:i:s');

        $from_name = $chinbxsx['from_name'];

        if($from_id != $userId){
          $from_image = $chinbxsx['from_image'];
          $msgclass = 'msgmRec';
        }else{
          $from_image = $userImage;
          $msgclass = 'msgmSend';
        }


      // if($get_date > $get_date){
            echo "<div class='msgm $msgclass'><img class='cmavsm' id='cmavsm' style='background-image: url($from_image);' /><p class='smRec'>$message</p><span class='date_span'>$senddate</span></div>";
      // }

      }


    $conn->close();


 }

?>

The mistake is: get the last message every 1 second. every time without stop it. I want to get the last message one time without loop the last message. thanks.

Answer 1

Using Ajax for chat will have poor performance always. You must consider using Web sockets.

See the below link for a sample

https://phppot.com/php/simple-php-chat-using-websocket/

Answer 2

I can't warranty this will be a fixed code, but it will give you the idea of how to discard a message on the client side if already received:

CLIENT SIDE:

<script>

/* Other code ... */

// Global variable for save the latest message ID.
var _latestMessageID = -1;

$(document).ready(function()
{
    // Start getting messages...

    setInterval(
        function() {loadlastmsg();},
        1000
    );
});

function loadlastmsg()
{
    var fromIdl = "<?php echo $chat_from_id;?>";
    var formData = {fromIdl: fromIdl};

    $.ajax({
        type:'POST',
        url:'loadSingle.php',
        data: $.param(formData),
        cache: false,
        success: function(data)
        {
            if (data && data["ID"] > _latestMessageID)
            {
                $('#mainmsgs').append(data["message"]);
                _latestMessageID = data["ID"];
            }
        }
    });
}

</script>

SERVER SIDE:

<?php

require_once 'config/config.php';

if(isset($_POST["fromIdl"]) && $_POST["fromIdl"])
{
    $chat_from_ids = $_POST["fromIdl"];
    mysqli_set_charset($conn,"utf8mb4");
    $chinbox = array();

    $result=$conn->query(
        "SELECT *
         FROM chat
         WHERE id = (SELECT MAX(id)
                     FROM chat
                     WHERE (to_id=$userId AND from_id=$chat_from_ids)
                     OR (to_id=$chat_from_ids AND from_id=$userId))
         ORDER BY chat.send_date DESC LIMIT 1"
    );

    // Since the query has LIMIT of 1 this should only loop one time.

    while ($chinbxsx = mysqli_fetch_assoc($result))
    {
        $chinbox[] = $chinbxsx;
        $from_id =  $chinbxsx['from_id'];
        $subject =  $chinbxsx['subject'];
        $message =  $chinbxsx['message'];
        $get_date = $chinbxsx['send_date'];
        $senddate = date_create($chinbxsx['send_date']);
        $senddate = date_format($senddate, 'Y/m/d H:i:s');
        $from_name = $chinbxsx['from_name'];

        if ($from_id != $userId)
        {
            $from_image = $chinbxsx['from_image'];
            $msgclass = 'msgmRec';
        }
        else
        {
            $from_image = $userImage;
            $msgclass = 'msgmSend';
        }

        $msgID = $chinbxsx['id'];
    }

    $returnArray = array();
    $returnArray["ID"] = $msgID;
    $returnArray["message"] = "<div class='msgm $msgclass'><img class='cmavsm' id='cmavsm' style='background-image: url($from_image);' /><p class='smRec'>$message</p><span class='date_span'>$senddate</span></div>";

    echo json_encode($result);    
    $conn->close();
 }

?>