How to determine if a file has been modified in php

php method to determine whether a file has been modified: first create a form and submit the file to be determined; then obtain the file path submitted in the form; finally use the filemtime() function to determine the submitted file.

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php method to determine whether a file has been modified:

Key technology:

Main application of this examplefilectime() and filemtime() functions detect the last incode change time and last modification time of the file, and apply the date() function to format the timestamp returned by the detection.

filectime() function returns the last change time of the inode of the specified file filename. The syntax is as follows:

int filectime(string filename);

If successful, the UNIX timestamp will be returned, otherwise FALSE will be returned.

Design Process:

First, design the web page, then create a form and submit the file to be judged through the file field. Then, obtain the file path submitted in the form and apply filectime() and filemtime() The function detects the submitted file, and finally outputs the detection result.

The key code of the index.php file is as follows:

<?php 
  $file=iconv("utf-8","gb2312",$_POST[&#39;files&#39;]);           //实现编码格式的转换 
  if(file_exists($file)){                                  //判断文件是否存在 
          $change_time=filectime($file);                   //获取文件的最后incode时间 
          $time=date("Y-m-d h:i:s",$change_time);          //时间戳的格式化 
          $last_time=filemtime($file);                     //获取文件的最后修改时间 
          $times=date("Y-m-d h:i:s",$last_time);           //时间戳的格式化 
   }else{ 
          $result="该文件不存在"; 
   } 
?>

Core: Get the last access time of the file.

Not only the last modification time of the file can be obtained through the file system function, but also the last access time of the file can be obtained. The fileatime() function is used.

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