Example code for checking whether a file or directory exists in php

Check whether the file or directory exists. We use the commonly used function in php file_exists. This function can achieve the function I want. Please refer to it slowly below

It is a simple example code to check whether the file exists:

The code is as follows:

<?php 
$filename = &#39;/path/to/foo.txt&#39;; 
if (file_exists($filename)) { 
echo "The file $filename exists"; 
} else { 
echo "The file $filename does not exist"; 
} 
?>

If the file exists, the display result of executing the PHP file is:
The file C :blablaphphello.txt exists.
If the file does not exist, the displayed result of executing the PHP file is:
The file C:\blabla\phphello.txt does not exist.
You can also use the file_exists function to test Whether a certain directory exists, the sample code is as follows:

The code is as follows:

if (file_exists("C:\blabla\php")) 
{echo "yes";} 
else 
{echo "no";}

Example

The code is as follows:

/** 
* 文件或目录权限检查函数 
* 
* @access public 
* @param string $file_path 文件路径 
* @param bool $rename_prv 是否在检查修改权限时检查执行rename()函数的权限 
* 
* @return int 返回值的取值范围为{0 <= x <= 15}，每个值表示的含义可由四位二进制数组合推出。 
* 返回值在二进制计数法中，四位由高到低分别代表 
* 可执行rename()函数权限、可对文件追加内容权限、可写入文件权限、可
读取文件
权限。 
*/ 
function file_mode_info($file_path) 
{ 
/* 如果不存在，则不可读、不可写、不可改 */ 
if (!file_exists($file_path)) 
{ 
return false; 
} 
$mark = 0; 
if (
strtoupper
(substr(PHP_OS, 0, 3)) == &#39;WIN&#39;) 
{ 
/* 测试文件 */ 
$test_file = $file_path . &#39;/cf_test.txt&#39;; 
/* 如果是目录 */ 
if (is_dir($file_path)) 
{ 
/* 检查目录是否可读 */ 
$dir = @opendir($file_path); 
if ($dir === false) 
{ 
return $mark; //如果目录打开失败，直接返回目录不可修改、不可写、不可读 
} 
if (@readdir($dir) !== false) 
{ 
$mark ^= 1; //目录可读 001，目录不可读 000 
} 
@closedir($dir); 
/* 检查目录是否可写 */ 
$fp = @fopen($test_file, &#39;wb&#39;); 
if ($fp === false) 
{ 
return $mark; //如果目录中的文件创建失败，返回不可写。 
} 
if (@fwrite($fp, &#39;directory access testing.&#39;) !== false) 
{ 
$mark ^= 2; //目录可写可读011，目录可写不可读 010 
} 
@fclose($fp); 
@unlink($test_file); 
/* 检查目录是否可修改 */ 
$fp = @fopen($test_file, &#39;ab+&#39;); 
if ($fp === false) 
{ 
return $mark; 
} 
if (@fwrite($fp, "modify test.rn") !== false) 
{ 
$mark ^= 4; 
} 
@fclose($fp); 
/* 检查目录下是否有执行rename()函数的权限 */ 
if (@rename($test_file, $test_file) !== false) 
{ 
$mark ^= 8; 
} 
@unlink($test_file); 
} 
/* 如果是文件 */ 
elseif (is_file($file_path)) 
{ 
/* 以读方式打开 */ 
$fp = @fopen($file_path, &#39;rb&#39;); 
if ($fp) 
{ 
$mark ^= 1; //可读 001 
} 
@fclose($fp); 
/* 试着修改文件 */ 
$fp = @fopen($file_path, &#39;ab+&#39;); 
if ($fp && @fwrite($fp, &#39;&#39;) !== false) 
{ 
$mark ^= 6; //可修改可写可读 111，不可修改可写可读011... 
} 
@fclose($fp); 
/* 检查目录下是否有执行rename()函数的权限 */ 
if (@rename($test_file, $test_file) !== false) 
{ 
$mark ^= 8; 
} 
} 
} 
else 
{ 
if (@is_readable($file_path)) 
{ 
$mark ^= 1; 
} 
if (@is_writable($file_path)) 
{ 
$mark ^= 14; 
} 
} 
return $mark; 
}

PHP Determine whether the directory exists

The code is as follows:

/**************************************************** 
* 将xml数据流，写入到xml文件 
* @param $xmlData 
* @return bool|string 
*/ 
function writeXmlFile($xmlData) 
{ 
$time = time(); //获取
时间戳
，用于给文件命名 
$path = dirname(FILE); //获取当前绝对路径 
$path = 
substr_replace
($path, "", stripos($path, "actions\data")); //将此文件所在的固有路径替换成空 
$path .= "xmlFiles\"; //存放目录名 
/*判断目标目录是否存在，不存在则新建*/ 
if(!is_dir($path)) 
{ 
mkdir($path); //新建目录 
} 
/*记录完整路径和文件名*/ 
$filePathAndName = $path.$time.".xml"; 
/*打开文件，文件名为<时间戳> + <.xml>*/ 
$fp = fopen($filePathAndName, "w"); 
if(!$fp) 
{ 
return false; 
} 
/*写入文件流*/ 
$flag = fwrite($fp, $xmlData); 
if(!$flag) 
{ 
return false; 
} 
fclose($fp); 
return $filePathAndName; 
}

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