Backend Development
PHP Tutorial
PHP creates files (folders) and directory operation codes_PHP tutorial
PHP creates files (folders) and directory operation codes_PHP tutorial
1. Directory operation
The first is the function to read from the directory, opendir(), readdir(), closedir(). When used, the file handle is opened first, and then iteratively listed:
$base_dir="filelist/";
$fso=opendir($base_dir) ;
echo $base_dir."
";
while($flist=readdir($fso)){
echo $flist."
";
}
closedir($fso)
?>
This is a program that returns the files and directories under the file directory (0 files will return false).
Yes When you need to know the 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($path) to return the remaining space of the view space.
Create command :
mkdir($path,0777): 0777 is the permission code, which can be set by the umask() function under non-window conditions.
rmdir($path): will delete the file with the path in $path.
Two , File operations
● Create new files
First, determine the permissions of the directory where the file you want to create is located; the recommended device is 777. Then, it is recommended to use an absolute path for the name of the new file.
$filename="test.txt";
$fp=fopen("$filename", "w+"); //Open the file pointer and create the 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
● Reading a 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.:
$file = 'dirlist.php';
if (is_readable($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
$file = "filelist.php";
if (file_exists($file) == false) {
die(' File does not exist');
}
$data = file_get_contents($file);
echo htmlentities($data);
?>
But file_get_contents function It is not supported on lower versions. You can create a handle to the file first, and then use a pointer to read the entire file:
There is also a way to read binary files:
$data = implode('', file($file));
● Write file
In the same way as reading a file, first check if it can be written:
< ?php
$file = 'dirlist.php';
if (is_writable($file) == false) {
die("You have no right to write!");
}
?>
If you can write, you can use the file_put_contents function to write:
$file = 'dirlist.php';
if (is_writable($file) == false) {
die('I am a chicken, 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). It cannot be used in lower versions of PHP. You can use the following method:
$f = fopen($file, 'w');
fwrite($f, $data);
fclose($f);
Replace it.
Sometimes you need to lock when writing a file, then write:
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 write 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;
}
● Copy and delete files
It is very easy to delete files in php, use the unlink function:
$file = 'dirlist.php';
$ result = @unlink ($file);
if ($result == false) {
echo 'The mosquitoes were driven away';
} else {
echo 'Cannot be driven away';
}
?>
That’s it.
Copying files is also easy:
$file = 'yang.txt';
$newfile = 'ji.txt'; # The parent folder of this file must be writable
if (file_exists($file) == false) {
die ('The demo is not online and cannot be copied');
}
$result = copy($file, $newfile);
if ($result == false) {
echo 'Copy memory ok';
}
?>
You can use the rename() function to rename a folder. Other operations can be achieved by combining these functions.
● Get file attributes
Let me talk about a few common functions:
Get the latest modification time:
$file = 'test.txt';
echo date('r', filemtime ($file));
?>
The returned timestamp is the unix timestamp, which is commonly used in caching technology.
Related is also getting the last time fileatime was accessed (), filectime() When the file's permissions, owner, all groups or other metadata in the inode are updated, the fileowner() function returns the file owner
$owner = posix_getpwuid(fileowner($file));
(non-window system), ileperms() obtains file permissions,
< ;?php
$file = 'dirlist.php';
$perms = substr(sprintf('%o', fileperms($file)), -4);
echo $perms;
?>
filesize() returns the number of bytes of the file size:
// Output is similar: somefile.txt: 1024 bytes
$filename = 'somefile.txt';
echo $filename . ': ' . filesize($ filename) . ' bytes';
?>
To get all the information of the file, there is a function stat() function that returns an array:
$file = 'dirlist.php';
$perms = stat($file);
var_dump($perms);
?>
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1664
14
1423
52
1317
25
1268
29
1243
24
Explain JSON Web Tokens (JWT) and their use case in PHP APIs.
Apr 05, 2025 am 12:04 AM
JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,
Explain late static binding in PHP (static::).
Apr 03, 2025 am 12:04 AM
Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.
What are PHP magic methods (__construct, __destruct, __call, __get, __set, etc.) and provide use cases?
Apr 03, 2025 am 12:03 AM
What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
PHP and Python: Comparing Two Popular Programming Languages
Apr 14, 2025 am 12:13 AM
PHP and Python each have their own advantages, and choose according to project requirements. 1.PHP is suitable for web development, especially for rapid development and maintenance of websites. 2. Python is suitable for data science, machine learning and artificial intelligence, with concise syntax and suitable for beginners.
PHP in Action: Real-World Examples and Applications
Apr 14, 2025 am 12:19 AM
PHP is widely used in e-commerce, content management systems and API development. 1) E-commerce: used for shopping cart function and payment processing. 2) Content management system: used for dynamic content generation and user management. 3) API development: used for RESTful API development and API security. Through performance optimization and best practices, the efficiency and maintainability of PHP applications are improved.
PHP: A Key Language for Web Development
Apr 13, 2025 am 12:08 AM
PHP is a scripting language widely used on the server side, especially suitable for web development. 1.PHP can embed HTML, process HTTP requests and responses, and supports a variety of databases. 2.PHP is used to generate dynamic web content, process form data, access databases, etc., with strong community support and open source resources. 3. PHP is an interpreted language, and the execution process includes lexical analysis, grammatical analysis, compilation and execution. 4.PHP can be combined with MySQL for advanced applications such as user registration systems. 5. When debugging PHP, you can use functions such as error_reporting() and var_dump(). 6. Optimize PHP code to use caching mechanisms, optimize database queries and use built-in functions. 7
The Enduring Relevance of PHP: Is It Still Alive?
Apr 14, 2025 am 12:12 AM
PHP is still dynamic and still occupies an important position in the field of modern programming. 1) PHP's simplicity and powerful community support make it widely used in web development; 2) Its flexibility and stability make it outstanding in handling web forms, database operations and file processing; 3) PHP is constantly evolving and optimizing, suitable for beginners and experienced developers.
Explain the match expression (PHP 8 ) and how it differs from switch.
Apr 06, 2025 am 12:03 AM
In PHP8, match expressions are a new control structure that returns different results based on the value of the expression. 1) It is similar to a switch statement, but returns a value instead of an execution statement block. 2) The match expression is strictly compared (===), which improves security. 3) It avoids possible break omissions in switch statements and enhances the simplicity and readability of the code.
