PHP file directory operation implementation program (1/2)_PHP tutorial

There are specific functions for file or directory operations in php, such as fopen, rdir, filesize, opendir, readdir, fcolse, fread, etc. are all file and directory operation functions.

2. Directory operations

The first introduction is a function that reads from a directory, opendir(), readdir(), closedir(). When used, the file handle is opened first, and then iteratively listed:

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代码如下	复制代码
$base_dir = "filelist/"; $fso = opendir($base_dir); echo $base_dir." " ; while($flist=readdir($fso)){ echo $flist." " ; } closedir($fso) ?>

$base_dir = "filelist/"; $fso = opendir($base_dir);

echo $base_dir."

---

" ; while($flist=readdir($fso)){

echo $flist."
" ;

}

代码如下	复制代码
mkdir($path,0777)

closedir($fso)

?>

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rmdir($path)

This is a program that returns the files and directories under the file directory (0 files will return false).

Sometimes you need to know directory information. You can use dirname($path) and basename($path) to return the directory part and file name part of the path respectively. You can use disk_free_space($path) to return the free space.

Create command:

代码如下	复制代码
$d = dir("/etc/php5"); echo "Handle: " . $d->handle . "n"; echo "Path: " . $d->path . "n"; while (false !== ($entry = $d->read())) { echo $entry."n"; } $d->close(); ?>

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mkdir($path,0777)

, 0777 is the permission code, which can be set by the umask() function under non-window conditions.

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rmdir($path)

The file with the path in $path will be deleted.

dir -- directory class is also an important class for operating file directories. It has three methods, read, rewind, and close. This is a pseudo-object-oriented class. It first uses open file handles, and then uses pointers. Read., see the php manual here:

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$d = dir("/etc/php5"); echo "Handle: " . $d->handle . "n"; echo "Path: " . $d->path . "n"; while (false !== ($entry = $d->read())) { echo $entry."n"; } $d->close(); ?>

Output:

Handle: Resource id #2

代码如下	复制代码
$file = 'dirlist.php'; if (is_readable($file) == false) { die('文件不存在或者无法读取'); } else { echo '存在'; } ?>

Path: /etc/php5 . .. apache cgi cli File attributes are also very important. File attributes include creation time, last modification time, owner, file group, type, size, etc. Let’s focus on file operations. 3. File operations ● Read file First, check whether a file can be read (permission issue), or whether it exists. We can use the is_readable function to obtain the information.:

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$file = 'dirlist.php'; if (is_readable($file) == false) { die('File does not exist or cannot be read'); } else { echo 'exists'; } ?>

The function to determine the existence of a file also includes file_exists (demonstrated below), but this is obviously not as comprehensive as is_readable. When a file exists, you can use

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代码如下	复制代码
$file = "filelist.php"; if (file_exists($file) == false) { die('文件不存在'); } $data = file_get_contents($file); echo htmlentities($data); ?>

$file = "filelist.php";
if (file_exists($file) == false) {
die('File does not exist');
}
$data = file_get_contents($file);
echo htmlentities($data);
?>

However, the file_get_contents function is not supported on lower versions. You can first create a handle to the file, and then use a pointer to read the entire file:

代码如下	复制代码
$fso = fopen($cacheFile, 'r'); $data = fread($fso, filesize($cacheFile)); fclose($fso);

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$fso = fopen($cacheFile, 'r'); $data = fread($fso, filesize($cacheFile)); fclose($fso);

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$data = implode('', file($file));

There is another way to read binary files:

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$data = implode('', file($file));

● Write file

代码如下	复制代码
$file = 'dirlist.php'; if (is_writable($file) == false) { die("我是鸡毛,我不能"); } ?>

Same as reading a file, first check if it can be written:

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代码如下	复制代码
$file = 'dirlist.php'; if (is_writable($file) == false) { die('我是鸡毛,我不能'); } $data = '我是可鄙,我想要'; file_put_contents ($file, $data); ?>

$file = 'dirlist.php';
if (is_writable($file) == false) {
die("I am a chicken feather, I can't");
}
?>

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$f = fopen($file, 'w'); fwrite($f, $data); fclose($f);

If you can write, you can use the file_put_contents function to write:

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$file = 'dirlist.php'; if (is_writable($file) == false) { die('I am a chicken feather, I can't'); } $data = 'I am despicable, I want'; file_put_contents ($file, $data); ?>

The file_put_contents function is a newly introduced function in php5 (if you don’t know it exists, use the function_exists function to determine it first). Lower versions of php cannot be used. You can use the following method:

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$f = fopen($file, 'w'); fwrite($f, $data); fclose($f);

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When writing a file, sometimes you need to lock it, and then write:

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代码如下	复制代码
function cache_page($pageurl,$pagedata){ if(!$fso=fopen($pageurl,'w')){ $this->warns('无法打开缓存文件.');//trigger_error return false; } if(!flock($fso,LOCK_EX)){//LOCK_NB,排它型锁定 $this->warns('无法锁定缓存文件.');//trigger_error return false; } if(!fwrite($fso,$pagedata)){//写入字节流,serialize写入其他格式 $this->warns('无法写入缓存文件.');//trigger_error return false; } flock($fso,LOCK_UN);//释放锁定 fclose($fso); return true; }

function cache_page($pageurl,$pagedata){
if(!$fso=fopen($pageurl,'w')){
$this->warns('Unable to open cache file.');//trigger_error
return false;
}
if(!flock($fso,LOCK_EX)){//LOCK_NB, exclusive lock
$this->warns('Unable to lock cache file.');//trigger_error
return false;
}
if(!fwrite($fso,$pagedata)){//Write byte stream, serialize writes other formats
$this->warns('Unable to write to cache file.');//trigger_error
return false;
}
flock($fso,LOCK_UN);//Release the lock
fclose($fso);
return true;
}

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http://www.bkjia.com/PHPjc/629155.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/629155.htmlTechArticleThere are specific functions for file or directory operations in php, such as fopen, rdir, filesize, opendir, readdir , fcolse, fread, etc. are all file and directory operation functions. 2. Directory operation The first thing to introduce is...