PHP and file Operations _php tutorial

First, directory operations

The first is the function that reads from the directory, Opendir (), Readdir (), Closedir (), which is used when the file handle is opened, and then the iteration is listed:
$base _dir= "filelist/";
$fso =opendir ($base _dir);
echo $base _dir. " ";
while ($flist =readdir ($FSO)) {
echo $flist. "
";
}
Closedir ($FSO)
?>
This is the return file directory under which the file is already in the directory program (0 file will return false).

Sometimes you need to know the directory information, you can use DirName ($path) and basename ($path), respectively, return the directory portion of the path and the file name part, the Disk_free_space ($path) to return to view the space remaining space.

To create a command:

mkdir ($path, 0777): 0777 is the permission code, which can be set under non-window umask () function.

RmDir ($path): will delete the path in the $path file.

Second, the file operation

New file

First, determine the permissions of the directory where you want to create the new file; The recommended device is 777. Then, the name of the new file is recommended to use an absolute path.
$filename = "Test.txt";
$FP =fopen ("$filename", "w+"); Open file pointer, create file
if (!is_writable ($filename)) {
Die ("File:". $filename. " Not writable, please check! ");
}
Fwrite ($filename, "anything you want-to-write to $filename.";
Fclose ($FP); Close pointer

Read the file

The first is a file to see if it can read (permission problems), or there is no, we can use the Is_readable function to obtain information.:

$file = ' dirlist.php ';
if (is_readable ($file) = = False) {
Die (' file does not exist or cannot be read ');
} else {
echo ' presence ';
}
?>

The function of judging the existence of a file is also file_exists (shown below), but this is obviously not is_readable comprehensive. When a file exists, it can be used

$file = "filelist.php";
if (file_exists ($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 earlier versions, you can create a handle to the file first, and then read all with the pointer:

There is also a way to read a binary file:

$data = Implode (', File ($file));

Write a file

and read the file the same way, first see if it can write:

$file = ' dirlist.php ';
if (is_writable ($file) = = False) {
Die ("write!");
}
?>

If you can write it, you can use the File_put_contents function to write:

$file = ' dirlist.php ';
if (is_writable ($file) = = False) {
Die (' I'm chicken feathers, I can't ');
}
$data = ' I am contemptible, I want to ';
File_put_contents ($file, $data);
?>

file_put_contents function in the php5 of the newly introduced function (do not know the existence of the function_exists function first to judge) the lower version of PHP is not available, you can use the following way:

$f = fopen ($file, ' w ');
Fwrite ($f, $data);
Fclose ($f);

Replace it.

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

function Cache_page ($pageurl, $pagedata) {
if (! $fso =fopen ($pageurl, ' W ')) {
$this->warns (' cannot open cache file. '); /trigger_error
return false;
}
if (!flock ($fso, lock_ex)) {//LOCK_NB, exclusive type lock
$this->warns (' cannot lock cache file. '); /trigger_error
return false;
}
if (!fwrite ($fso, $pagedata)) {//write byte stream, serialize write to other format
$this->warns (' cannot write to cache file. '); /trigger_error
return false;
}
Flock ($fso, lock_un);//Release lock
Fclose ($FSO);
return true;
}

Copy, delete files

PHP Delete Files is very easy, with the unlink function simple operation:

$file = ' dirlist.php ';
$result = @unlink ($file);
if ($result = = False) {
Echo ' Mosquitoes have driven away ';
} else {
Echo ' cannot be driven away ';
}
?>

Can.

Copying files is also easy:

$file = ' yang.txt ';
$newfile = ' ji.txt '; # The parent folder of this file must be able to write
if (file_exists ($file) = = False) {
Die (' sample not online, cannot copy ');
}
$result = Copy ($file, $newfile);
if ($result = = False) {
echo ' Copy memory OK ';
}
?>

You can use the rename () function to rename a folder. The other operations are done by combining these functions.

Get file properties

I say a few common functions:
Gets the last modified time:

$file = ' test.txt ';
echo Date (' R ', Filemtime ($file));
?>

Returns a timestamp that says Unix, which is commonly used in caching techniques.

Related to the last time accessed Fileatime (), Filectime () when the permissions of the file, the owner, the metadata in all groups or other inode are updated, the Fileowner () function returns the file owner
$owner = Posix_getpwuid (Fileowner ($file));
(Non-Window System), Ileperms () Gets the file permissions,

$file = ' dirlist.php ';
$perms = substr (sprintf ('%o ', Fileperms ($file)),-4);
Echo $perms;
?>

FileSize () returns the number of bytes in the file size:

Output similar to: somefile.txt:1024 bytes

$filename = ' somefile.txt ';
Echo $filename. ': ' . FileSize ($filename). ' bytes ';

?>

To get all the information for a file, there is a function stat () function that returns an array:

$file = ' dirlist.php ';
$perms = stat ($file);
Var_dump ($perms);
?>

http://www.bkjia.com/PHPjc/477220.html www.bkjia.com true http://www.bkjia.com/PHPjc/477220.html techarticle first, the directory operation is the function read from the directory, Opendir (), Readdir (), Closedir (), when using the first open the file handle, and then the iteration list: PHP $base _dir=filelist/; $fso =opend ...

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