我'm using Eliza Witkowska' s Ajax自动刷新代码：http://blog.codebusters.pl/en/entry/ajax-auto-refresh-volume-ii
我已经改变了代码，所以我可以从url传递变量 . 除了一行代码之外，一切都很好 . 代码行是检查新记录的数据库查询的一部分 . 当我尝试将变量传递给查询时，自动刷新停止工作（所有其他功能继续工作） . 如果我使用静态值，它工作正常 .
静态值（这是有效的）
$result = $this->db->query('SELECT counting FROM chats WHERE id=1 AND AgentID=3 AND UserID=25');
变量（这不起作用）
$result = $this->db->query('SELECT counting FROM chats WHERE id=1 AND AgentID='.$AgentID.' AND UserID='.$UserID.'');
将变量传递到同一脚本中的另一个函数没有问题 . 所以我被困住了几天 . 任何帮助，不胜感激 .
db.php中
class db{
/**
* db
*
* @var $ public $db;
*/
public $db;
function __construct(){
$this->db_connect('###SERVER###','###USERNAME###','###PASSWORD###','###DATABASE###'); //my database information
}
function db_connect($host,$user,$pass,$database){
$this->db = new mysqli($host, $user, $pass, $database);
if($this->db->connect_errno > 0){
die('Unable to connect to database [' . $this->db->connect_error . ']');
}
}
//////////////////////////////
//This is the function that is having an issue when I pass it variables
//////////////////////////////
function check_changes(){
global $UserID; //Declaring my variable
global $AgentID; //Declaring my variable
$result = $this->db->query('SELECT counting FROM chats WHERE id=1 AND AgentID='.$AgentID.' AND UserID='.$UserID.'');
if($result = $result->fetch_object()){
return $result->counting;
}
return 0;
}
//////////////////////////////
//This function has no problem, even when I pass it variables
//////////////////////////////
function get_news(){
global $UserID;
global $AgentID;
if($result = $this->db->query('SELECT * FROM chats WHERE id<>1 AND AgentID='.$AgentID.' AND UserID='.$UserID.' ORDER BY add_date ASC LIMIT 50')){
$return = '';
while($r = $result->fetch_object()){
if ($r->ChatType==1) { //ChatType is a field in the table that distinguishes Agent texts from User Texts
$return .= ''.htmlspecialchars($r->title).'';
} else {
$return .= '<div align="right">'.htmlspecialchars($r->title).'</div>';
}
}
return $return;
}
}
}
以下是其他文件：
的index.php
<?php
$AgentID = $_REQUEST["AgentID"]; //Grabing AgentID from the URL
$UserID = $_REQUEST["UserID"]; //Grabing UserID from the URL
require('common.php');
?>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Admin</title>
<script src="jquery-1.10.2.min.js"></script>
<script>
/* AJAX request to checker */
function check(){
$.ajax({
type: 'POST',
url: 'checker.php?AgentID=<? echo $AgentID; ?>&UserID=<? echo $UserID; ?>', //This line has been updated by passing parameters
dataType: 'json',
data: {
counter:$('#message-list').data('counter')
}
}).done(function( response ) {
/* update counter */
$('#message-list').data('counter',response.current);
/* check if with response we got a new update */
if(response.update==true){
$('#message-list').html(response.news);
var audio = new Audio('img/solemn.mp3');
audio.play();
}
});
}
//Every 2 sec check if there is new update
setInterval(check,2000);
</script>
<style>
body {
margin:0px;
padding:0px;
vertical-align:top;
}
</style>
</head>
<body>
<?php /* Our message container. data-counter should contain initial value of counter from database */ ?>
<br>
<div id="message-list" data-counter="<?php echo (int)$db->check_changes();?>">
<?php echo $db->get_news();?>
</div>
</body>
</html>
checker.php
<?php require('common.php');
//get current counter
$data['current'] = (int)$db->check_changes();
//set initial value of update to false
$data['update'] = false;
//check if it's ajax call with POST containing current (for user) counter;
//and check if that counter is diffrent from the one in database
if(isset($_POST) && !empty($_POST['counter']) && (int)$_POST['counter']!=$data['current']){
$AgentID = $_REQUEST["AgentID"]; //passing my variable to db.php
$UserID = $_REQUEST["UserID"]; //passing my variable to db.php
$data['news'] = $db->get_news();
$data['update'] = true;
}
//just echo as JSON
echo json_encode($data);
/* End of file checker.php */
?>
的common.php
<?php
require_once ('db.php'); //get our database class
$db = new db();
/* end of file common.php */
?>
1 回答
我认为问题是在
checker.php中包含数据库连接时变量不可用 - 声明变量然后包含数据库连接 .另外，我建议不要使用
global表达式来定义db类方法中的变量，而是将它们作为参数传递 . 我希望以下可能有用 - 虽然没有经过测试 . 这个在sql中使用变量的方法有或者应该关注 - 它很容易受到可怕的sql injection~更好的方法是在db类中使用prepared statements并使用bind_param()方法绑定$agentID和$UserID.