php-来自mysql的长轮询信息不起作用
作者：互联网
我正在尝试与ajax,jquery,php和mysql进行基于长轮询的聊天,但是似乎有些错误(也是长轮询的新手).
index.php文件：
<?php
include 'db.php';
$result = mysql_query("SELECT id FROM chatpoll ORDER BY id DESC LIMIT 1");
while($row = mysql_fetch_array($result))
{
$old_msg_id = $row['id'];
}
?>
<html>
<head>
<script src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript" charset="utf-8">
var old_msg_id = <?php echo $old_msg_id; ?>;
function waitForMsg(){
$.ajax({
type: "GET",
url: "poll.php?old_msg_id=" + old_msg_id,
async: true,
cache: false,
success: function(data){
var json = eval('(' + data + ')');
if(json['msg'] != "") {
alert("New msg added to base!");
}
old_msg_id = json['old_msg_id'];
setTimeout('waitForMsg()',1000);
},
error: function(XMLHttpRequest, textStatus, errorThrown){
alert("error: " + textStatus + " (" + errorThrown + ")");
setTimeout('waitForMsg()',15000);
}
});
}
$(document).ready(function(){
waitForMsg();
});
function load(old_msg_id) //part of code which i'm not using yet
{
$.get('getmsg.php?last_msg_id='+ old_msg_id, function(data){
$('#chat').append(data);
}, 'html');
}
</script>
</head>
<body>
<div id="chat">
</div>
</body>
</html>
和poll.php
<?php
include 'db.php';
$old_msg_id = $_GET['old_msg_id'];
$result = mysql_query("SELECT id FROM chatpoll ORDER BY id DESC LIMIT 1");
while($row = mysql_fetch_array($result))
{
$last_msg_id = $row['id'];
}
while($old_msg_id >= $last_msg_id) {
usleep(1000);
clearstatcache();
$old_msg_id = $last_msg_id;
}
$response = array();
$response['msg'] = 'new';
$response['old_msg_id'] = $old_msg_id;
echo json_encode($response);
?>
它在index.php和poll.php中都没有显示任何错误,但是当我插入ID大于old_msg_id的数据时,没有任何反应.
解决方法:
将您的poll.php文件中的代码更改为以下内容：
<?php
include 'db.php';
$old_msg_id = $_GET['old_msg_id'];
$result = mysql_query("SELECT id FROM chatpoll ORDER BY id DESC LIMIT 1");
while($row = mysql_fetch_array($result))
{
$last_msg_id = $row['id'];
}
while($last_msg_id <= $old_msg_id)
{
usleep(1000);
clearstatcache();
$result = mysql_query("SELECT id FROM chatpoll ORDER BY id DESC LIMIT 1");
while($row = mysql_fetch_array($result))
{
$last_msg_id = $row['id'];
}
}
$response = array();
$response['msg'] = 'new';
$response['old_msg_id'] = $last_msg_id;
echo json_encode($response);
?>
标签：long-polling,php,jquery,mysql,ajax 来源： https://codeday.me/bug/20191011/1892555.html