[英]Check for a database update using PHP and AJAX
我有一个网站,当用户单击 canvas 时,他会使用它并将其推送到数据库中。 它在一秒钟内为每个用户绘制 10 次。
setInterval(function(){
$.ajax({
url: 'data/canvasSave.php',
success: function(data) {
$('.result').html(data);
console.log(data);
imageCanvas = data;
}
});
let img = new Image();
img.src = imageCanvas;
context.clearRect(0, 0, canvas.width, canvas.height);
ctx.drawImage(img, 0 , 0, canvas.width, canvas.height);
}, 100);
现在我注意到这不是最好的方法。 但是有没有检查数据库更新的好方法? 我尝试了一些 if 语句,但没有一个真正起作用。
您可以使用
PHP sockets
通过 WebSockets 跟踪 MySQL 数据库更改。
文件:index.php
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>MySQL Tracker</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/uikit@3.7.4/dist/css/uikit.min.css" />
</head>
<body>
<div class="uk-container uk-padding">
<h2>Users</h2>
<p>Tracking users table with WebSockets</p>
<table class="uk-table">
<thead>
<tr>
<th>User ID</th>
<th>User Name</th>
</tr>
</thead>
<tbody>
<?php
$connection = mysqli_connect(
'localhost',
'root',
PASSWORD,
DB_NAME
);
$users = mysqli_query($connection, 'SELECT * FROM users');
while ($user = mysqli_fetch_assoc($users)) {
echo '<tr>';
echo '<td>' . $user['id'] . '</td>';
echo '<td>' . $user['name'] . '</td>';
echo '</tr>';
}
?>
</tbody>
</table>
</div>
</body>
</html>
接下来,使用以下代码在 HTML 文件中添加 PieSocket-JS WebSocket 库:
现在,我们准备好连接到 WebSocket 频道并开始从服务器接收即时更新。 将以下代码添加到您的 index.php 文件以建立 websocket 连接。
<script>
var piesocket = new PieSocket({
clusterId: 'CLUSTER_ID',
apiKey: 'API_KEY'
});
// Connect to a WebSocket channel
var channel = piesocket.subscribe("my-channel");
channel.on("open", ()=>{
console.log("PieSocket Channel Connected!");
});
//Handle updates from the server
channel.on('message', function(msg){
var data = JSON.parse(msg.data);
if(data.event == "new_user"){
alert(JSON.stringify(data.data));
}
});
</script>
让我们创建一个名为 admin.php 的文件,它会在每次访问用户表时添加一个条目。
<?php
$connection = mysqli_connect(
'localhost',
'root',
PASSWORD,
DB_NAME
);
mysqli_query($connection, "INSERT INTO users .....");
?>
上面给出的代码片段每次通过 CLI 或从网络服务器执行时都会在用户表中添加一个条目。
使用以下 PHP function 来执行此操作。
<?php
function publishUser($event){
$curl = curl_init();
$post_fields = [
"key" => "PIESOCKET_API_KEY",
"secret" => "PIESOCKET_API_SECRET",
"channelId" => "my-channel",
"message" => $event
];
curl_setopt_array($curl, array(
CURLOPT_URL => "https://PIESOCKET_CLUTER_ID.piesocket.com/api/publish",
CURLOPT_RETURNTRANSFER => true,
CURLOPT_CUSTOMREQUEST => "POST",
CURLOPT_POSTFIELDS => json_encode($post_fields),
CURLOPT_HTTPHEADER => array(
"Content-Type: application/json"
),
));
$response = curl_exec($curl);
print_r($response);
}
$connection = mysqli_connect(
'localhost',
'root',
PASSWORD,
DB_NAME
);
mysqli_query($connection, "INSERT INTO users .....");
$payload = json_encode([
"event" => "new_user",
"data" => [
"id"=> 1,
"name"=>"Test user"]
]);
publishUser($payload);
?>
例如,在 app/model/User.php 下的用户 model 中添加以下代码块
public static function boot() {
parent::boot();
static::created(function($user) {
publishUser(json_encode($user));
});
}
import requests
import json
url = "https://CLUSTER_ID.piesocket.com/api/publish"
payload = json.dumps({
"key": "API_KEY",
"secret": "API_SECRET",
"channelId": 1,
"message": { "text": "Hello world!" }
});
headers = {
'Content-Type': 'application/json'
}
response = requests.request("POST", url, headers=headers, data = payload)
print(response.text.encode('utf8'))
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.