Detailed explanation of how PHP's ob cache mechanism implements page staticization

This article mainly introduces the method of staticizing the page using PHP's ob caching mechanism. Interested friends can refer to it. I hope it will be helpful to everyone.

First introduce some common functions commonly used in ob cache in php

ob_start(): Turn on the caching mechanism

ob_get_contents(): Get the contents of the ob cache

ob_clean() Clear the contents of the ob cache, but do not close the cache

ob_end_clean() Clear the contents of the ob cache, and close the cache

ob_flush clears the cache, outputs the content, but does not close the cache

ob_end_flush clears the cache, outputs the content, and closes the cache

flush forces the content in the output cache to be refreshed

According to the provisions of the http protocol, the response content cannot be output before the response header. Therefore, if there is content output in front of the header() function, an error will occur. However, after using ob_start(), the response content will be put first. In the ob cache, the message header will not be sent before it is sent, which solves the problem of header() error!

Let’s talk about how to use PHP’s own ob cache mechanism to achieve page staticization. The sample code is as follows

<?php
  
    $id=$_REQUEST[&#39;id&#39;];
    
    //判断缓存文件是否存在，如果存在，直接输出
    if(file_exists(&#39;content&#39;.$id.&#39;.html&#39;)){
      echo file_get_contents(&#39;content&#39;.$id.&#39;.html&#39;);
      return;
    }
    
    //开启缓存机制
    ob_start();
    
    //到数据库中查询所需要的内容
    $conn=mysql_connect("localhost","root","root");
    mysql_select(&#39;db&#39;);
    mysql_query(&#39;set names utf8&#39;);
    
    $sql="select content from table_name where id=$id";
    $res=mysql_query($sql);
    $row=mysql_fetch_assoc($res);
    $content=$row[0];
    
    mysql_free_result($res);
    mysql_close($conn);
    echo $content;
    //将输出的内容保存到文件中，形成静态页面，在下次访问的时候，直接读取输出
    file_put_contents(&#39;content&#39;.$id.&#39;.html&#39;,ob_get_contents());


?>

As shown in the above code:

Save the content we query directly into the html file. If the file exists, output it. If it does not exist, access the database and execute Corresponding query process

If you want to set the expiration time of the file, you can add a judgment condition in the if statement to determine whether the cached file has expired, time()-the set expiration time

The above article uses PHP's ob cache mechanism to achieve page staticization. This is all the content shared by the editor. I hope it can give you a reference.

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