php中的聊天系统与长池，如何发送和获得消息在一起没有这么多延迟时间

Question

i提前m currently developing a chat aplication in php to a client using long polling. When the user send msgs i woud .abort() the getmsg() function and restart in on sendmsg() sucess (ajax call), but if the user send repeatedly msgs, the getmsg() get fired multiple times with same parameters, and if the other user is sending msgs too, i got repeatedly the same msgs. I got a way around it, without .abort() the getmsg() in sendmsg() it works well (ajax take care of both calls). But when the user send repeatedly msgs, i need to wait in the sleep() loop (getmsg()) to get all the msgs, even if there only a word in each. Is there a way to make the abort() fire just one time on consecutive msgs, or how i could make the sleep() to go lower (less seconds) when it finds a message? Wouldt it take so much of the server to do this check everytime? Thank s，很抱歉文本太长。以下是功能：

PHP

getmsg() (a php file, this is the function)
$aa = mysql_num_rows($chatresult);
$togetmsg = 2;
while($aa == 0 && $tried_times < 6) {
sleep($togetmsg);
$chatresult = mysql_query("query"); 
$aa = mysql_num_rows($chatresult);
$tried_times++;
}
while($crow = mysql_fetch_assoc($chatresult))
{
 get the messages and put in a var/array;       
} 
json_encode the msgs

sendmsg（）

 Just a query to insert the textarea value in the table.

JAVASCRIPT

getmsg（）：

  jack = $.ajax({
        type: "POST",
        url: "getmsg.php",
        data: {friend_chatid: friend_chatid, msg_id: msg_id},
        dataType: 'json',
        context: this,
        async: true,
        cache: false,
        timeout:30000,
        success: function(html){      
            $(this).find(".div").append(message);
            msg_id = 0;
            var _this = $(this);     
            setTimeout(
                getmsg, /* Request next message */
                1000 /* ..after 1 seconds */
            );
        },
        error: function(XMLHttpRequest, textStatus, errorThrown){
         if(textStatus==="abort" || errorThrown==="abort") {
     //   alert(textStatus);
    } else {
            setTimeout(
                getmsg, 
                3000);
    }

        }
    });

SENDMSG（）

$.ajax({
type: "POST",
url: "sendmsg.php",
data: {msg: msg, to: to},
context: this,
cache: false,
beforeSend: function () {
//   jack.abort(); // Commented cause i`m not using it now
$(this).val('');
    $(".div").append(msg); //
 },
success: function(html){
    //    getmsg(); // Commented cause i`m not using it now
  }
});  

它恢复了，我去掉了附加的数据部分，以便更好地阅读。javascript中的sendmsg（）将textarea值附加到聊天中，当用户按下回车键时，他们会用php将其发送到数据库，并且textarea有文本（为了更好地阅读，我去掉了这部分）。getmsg（）执行while循环，检查是否有使用mysql_num_rows的现有msg，并在有的情况下回显它们。

Answer 1

我认为可以使用clearTimeout来修复它。试试这个代码。

功能sendmsg()

// define a variable named `pollQueue` outsode of your function
var pollQueue = false;
// send message
$.ajax({
  type: "POST",
  url: "sendmsg.php",
  data: { msg : msg, to : to },
  context: this,
  cache: false,
  beforeSend: function() {
    // Check if getmsg is in queue
    if ( pollQueue ) {
      // if so clear the queue
      clearTimeout( pollQueue );
    }
    if ( jack ) {
      jack.abort();
    }
    $(this).val('');
    $(".div").append( msg );
  },
  success: function( html ) {
    // add to queue
    pollQueue = setTimeout( getmsg, 3000 );
  }
});