例1：循环延迟输出数据
<?php
if (ob_get_level() == 0) ob_start();
for ($i = 0; $i<10; $i++){
echo "<br> Line to show.";
echo str_pad('',4096)."\n";
ob_flush();
flush();
sleep(2);
}
echo "Done.";
ob_end_flush();
?>例2： 输出一些字符，达到条件后跳转
<?php
$web = "<h1>hello world</h1>";
echo $web;
ob_flush();
flush();
$data = 1;
while (1) {
sleep(1);
$data++;
if($data == 5) {
echo "<meta http-equiv='Refresh' content='0;URL=return.php'>";
break;
}
}例3：输出一些字符，达到条件后跳转。
<?php
$web = "<h1>hello world</h1>";
echo $web;
ob_flush();
flush();
while (1) {
$fp = fopen("s.txt", "r");
if(fgets($fp) == 1) {
echo "<meta http-equiv='Refresh' content='0;URL=return.php'>";
break;
}
fclose($fp);
sleep(1);
} laravel下写的一个实例，读取缓存的变化 控制器：
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Http\Requests;
use Cache;
class ScanLoginController extends Controller
{
private $_cacheKey = 'longlink';
public function index()
{
Cache::put($this->_cacheKey, 0, 0);
return view('test.index');
}
public function login(Request $request)
{
$i = 0;
while ($i < 250) {
$fp = Cache::get($this->_cacheKey);
if($fp == 1) {
return ['status' => 1];
}
$i++;
usleep(100000);
}
return ['status' => 0];
}
public function confirm()
{
Cache::put($this->_cacheKey, 1, 0);
dump(Cache::get($this->_cacheKey));
}
}视图：
<html>
<head>
<title>test</title>
<meta charset="UTF-8">
<script src="//cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<script>
$(function () {
function longlink() {
$("#show").text("正在连接");
$.get("{{ route('login') }}", function (data) {
if(data.status === 1) {
$("#show").text("有反应了");
} else {
$("#show").text("没反应，继续");
longlink();
}
}, "json");
}
$("#begin").click(function () {
longlink();
});
});
</script>
</head>
<body>
<div class="container">
<h1>长连接</h1>
<button id="begin" class="btn btn-success">开始</button>
<div id="show">我是一个长连接</div>
</div>
</body>
</html>