PHP gives file information

php Editor Xigua will introduce you how to use PHP to obtain file information. In web development, sometimes it is necessary to read information such as file attributes, size or modification time. PHP provides some built-in functions that can easily implement these functions. By using PHP functions, we can quickly obtain file information, which facilitates file operations and management during the development process. Next, let us explore how to use PHP to give file information.

PHP Get file information

Introduction

php Provides a series of built-in functions to obtain information about files, including file size, type, modification time, and file permissions. These functions are essential for file management, upload validation, and data manipulation.

Get file size

• filesize() The function returns the size of the specified file (in bytes).
• fstat() The function returns an array containing file status information, including file size.

Get file type

• filetype() The function returns the type of file (such as file, directory, symbolic link, etc.).
• mime_content_type() The function returns the MIME type of the file (such as text/plain, image/jpeg).

Get file modification time

• filemtime() The function returns the time when the file was last modified (expressed as a Unix timestamp).
• stat() The function returns an array containing file status information, including the last modification time.

Get file permissions

• fileperms() The function returns the permissions of the file (expressed as an octal number).
• lstat() The function returns the file permissions of the symbolic link, not the permissions of the file pointed to by the symbolic link.

Get path information

PHP also provides several functions to obtain file path information, including:

• dirname() Returns the directory path of the file.
• basename() Returns the base name of the file (excluding the path).
• pathinfo() Returns an array containing various information about the file path, such as directory path, file extension, and file name.

Other file information

In addition to the above functions, PHP also provides other functions to obtain file-related information, such as:

• is_readable() Check whether the file is readable.
• is_writable() Check whether the file is writable.
• is_executable() Check whether the file is executable.
• md5_file() Calculate the MD5 hash of a file.
• sha1_file() Calculate the SHA1 hash of a file.

Code Example

The following code example demonstrates how to use PHP to get information about a file:

$file = "myfile.txt";

// Get file size
$size = filesize($file);

// Get file type
$type = filetype($file);

// Get the file modification time
$mtime = filemtime($file);

// Get file permissions
$perms = fileperms($file);

// Get file path information
$dir = dirname($file);
$base = basename($file);
$info = pathinfo($file);

// Output file information
echo "File size: $size bytes<br>";
echo "File type: $type<br>";
echo "File modification time:", date("Y-m-d H:i:s", $mtime), "<br>";
echo "File permissions: $perms<br>";
echo "Directory path: $dir<br>";
echo "File base name: $base<br>";
echo "File name: {$info["filename"]}<br>";
echo "File extension: {$info["extension"]}";

Best Practices

When using PHP to obtain file information, please follow the following best practices:

• Make sure the file exists, otherwise an error will be raised.
• Consider file permissions and make sure the script has access to the file.
• Properly handle file paths to avoid path injection attacks.
• Use PHP's built-in functions instead of custom workarounds to ensure accuracy and efficiency.

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