Detailed explanation of the usage of php ob_start() cache function

This article introduces the usage of the function ob_start() used for cache control in PHP. Friends in need can refer to it.

In php, the ob_start() function is used to open the buffer. For example, if there is output before the header() function, including carriage return/space/line feed/, there will be an error of "Header had all ready send by".

At this time, you can first use ob_start() to open the buffer. The data block of the php code and the echo() output will enter the buffer and will not be output immediately.

There are four ways to open a buffer in php: 1. Used before header()

<?php
ob_start(); //打开缓冲区 
echo /"Hellon/"; //输出 
header("location:index.php"); //把浏览器重定向到index.php 
ob_end_flush();//输出全部内容到浏览器 
?>

2. The phpinfo() function can obtain client and server information and use a buffer to save client information.

<?php
ob_start(); //打开缓冲区 
phpinfo(); //使用phpinfo函数 
$info=ob_get_contents(); //得到缓冲区的内容并且赋值给$info 
$file=fopen(/'info.txt/',/'w/'); //打开文件info.txt 
fwrite($file,$info); //写入信息到info.txt 
fclose($file); //关闭文件info.txt 
?>

3. Static page technology

<?php
ob_start();//打开缓冲区 
 
//php页面的全部输出 
$content = ob_get_contents();//取得php页面输出的全部内容 
$fp = fopen("output00001.html", "w"); //创建一个文件，并打开，准备写入 
fwrite($fp, $content); //把php页面的内容全部写入output00001.html，然后…… 
fclose($fp); 
?> 

4, output code

<?php
Function run_code($code) { 
If($code) { 
   ob_start(); 
   eval($code); 
   $contents = ob_get_contents(); 
   ob_end_clean(); 
}else { 
   echo "错误！没有输出"; 
   exit(); 
} 
   return $contents; 
}