ricwein/filesystem

Filesystem abstraction layer

4.3.1 2021-05-06 10:23 UTC

README

This Library provides a Filesystem abstraction layer.

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;
use ricwein\FileSystem\Exceptions\Exception as FileSystemException;

try {

    $file = new File(new Storage\Disk(__DIR__, '/test', '/dir2', 'test.json'));
    $alt = new File(new Storage\Memory('{"some": "content"}'));

    // read file into output-buffer
    if ($file->isReadable()) {
        header('Content-Type: ' . $file->getType(true));
        echo $file->read();
    } else {
        header('Content-Type: ' . $alt->getType(true));
        echo $alt->read();
    }

} catch (FileSystemException $e) {

    http_response_code(500);
    echo json_encode(['errors' => [
        'status' => $e->getCode(),
        'title' => 'something went wrong',
        'detail' => $e->getMessage(),
    ]]);
}

Installation

composer require ricwein/filesystem

Overview

Let's begin with a short overview over the supported Filesystem classes and abstractions.

All classes uses the root-namespace ricwein\FileSystem.

Object-Types

A File is represented as a File Object and a Directory as a Directory Object.

Storage

Accessing the Objects (File/Directory) Content is abstracted as Storages. A File can be either:

  • a Disk file/directory at your local filesystem (Storage\Disk)
  • a Memory file, which only temporary exists in-memory (Storage\Memory)
  • a Stream a stream which points to a file or resource (Storage\Stream)
  • an abstract Flysystem file (Storage\Flysystem)

All Storage-Types must extend the abstract base class Filesystem\Storage.

WARNING: since storage-objects are mutable and php automatically handles class-objects as references when passed into a function (constructor), it's highly recommended using the clone keyword when storages are recycled between to FileSystem-Objects. DO NOT:

use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Storage;

$originalDir = new Directory(new Storage\Disk(__DIR__));
$copyDir = new Directory($originalDir->storage());

$copyDir->cd('test'); // will also changes $originalDir path!

DO:

use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Storage;

$originalDir = new Directory(new Storage\Disk(__DIR__));
$copyDir = new Directory(clone $originalDir->storage());

$copyDir->cd('test'); // $originalDir will stay in __DIR__

Exceptions

Accessing File/Directory Attributes can result in throwing Exceptions. All Exceptions extend Exceptions\Exception.

Usage: Files

All FileSystem-base-classes must be initialized using a Storage.

Methods

method description
read(?$offset, ?$length, $mode) read and return file-content, allows partial read with $offset and $length parameters, file is locked while reading with $mode
stream(?$offset, ?$length, $mode) stream file into output-buffer, file is locked while reading with $mode
write($content, $append, $mode) write $content to file, creates new file if it doesn't already exists, allows appended writing if $append isset, locks file with $mode
copyTo($destination [,Constraint $constraints]) copy file to new $destination Storage-adapter
moveTo($destination [,Constraint $constraints]) like copyTo(), but moves files instead
touch([bool $ifNewOnly]) create file if it doesn't exists, updates last-modified timestamp
remove() try to remove file
getType([bool $withEncoding]) guess files mime-type
getTime([Time $type]) get last-modified unix-timestamp
getDate([Time $type]) same as getTime(), but returns a DateTime object instead
getSize() calculate size
getHash([Hash $mode [,string $algo [,bool $raw]]]) calculates a hash over $mode with $algo algorithm
isReadable() is file readable?
isWriteable() is file writeable?
isSymlink() is file a symlink?
isFile() is selected path an actual file?
isDir() is selected path a directory? => always false for File instance
isDotfile() is file a hidden dot-file?
isValid() run constraints validation
getHandle([string $mode]) gets new file-Handle for binary file-access
storage() access internal storage adapter
getPath() fetch filesystem-path
getStream() returns Stream wrapper around internal resource pointing to actual file
dir([,int $constraints [,string $as [,...$arguments]]]) get parent Directory of file

Open and read a file from the local filesystem

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$file = new File(new Storage\Disk(__DIR__, 'test.txt'));
$content = $file->read();

or from in-memory-file

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$file = new File(new Storage\Memory('some content'));
$content = $file->read();

or from stream

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$file = new File(new Storage\Stream(fopen('php://output', 'wb')));
$content = $file->write('content');

or from a Flysystem object

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;
use League\Flysystem\Local\LocalFilesystemAdapter;

$file = new File(new Storage\Flysystem(new LocalFilesystemAdapter(__DIR__), 'test.txt'));
$content = $file->read();

Usage: Directories

Like Files, Directories must be initialized using a Storage.

Methods

method description
list($recursive) returns DirectoryIterator-Object to list directory-content as new File/Directory objects
mkdir() try to create directory
remove() try to remove directory
copyTo($destination [,Constraint $constraints]) copy directory recursively to new $destination Storage-adapter
getTime([Time $type]) get last-modified unix-timestamp
getDate([Time $type]) same as getTime(), but returns a DateTime object instead
getSize([bool $recursive]) calculate size
getHash([Hash $mode [,string $algo [,bool $raw]]]) calculates a hash over $mode with $algo algorithm
isReadable() is directory readable?
isWriteable() is directory writeable?
isSymlink() is directory a symlink?
isFile() is selected path a file? => always false for Directory instance
isDir() is selected path an actual directory?
isDotfile() is directory a hidden dot-file?
isValid() run constraints validation
storage() access internal storage adapter
getPath() fetch filesystem-path
file(string $filename [,int $constraints [,string $as [,...$arguments]]]) get File in current directory by name
dir(string $dirname [,int $constraints [,string $as [,...$arguments]]]) get Directory in current directory by name (clones storage!)

check if directory is readable

use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Storage;

$dir = new Directory(new Storage\Disk(__DIR__));
var_dump($dir->isReadable());

list all files inside a directory

use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Storage;

$hashes = [];
$dir = new Directory(new Storage\Disk(__DIR__));

foreach($dir->list(true)->files() as $file) {
    $hashes[$file->path()->filename] = $file->getHash();
}

Security

Using this filesystem-layer also provides some kind of security for usage with user-defined file-paths. Accessing file attributes or content is only done after checking against so called Constraints.

Constraints

Constraints are defined on initialization of File or Directory objects and are stored inside the internal Storage object. This allows Constraints-inheritance, if new FileSystem-objects are accessed from existing ones. Example:

use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Storage;
 use ricwein\FileSystem\Helper\Constraint;

$dir = new Directory(new Storage\Disk(__DIR__), Constraint::STRICT);
$file = $dir->file($_GET['filename']);

In this example, the $file object shares the Constraints (inherited) and safepath with $dir - allowing safely accessing a file in $dir from user defined parameters. Path traversal is therefore prevented.

The following constraints are set as default (as part of Constraint::STRICT), but can be overwritten with the second argument of the File($storage, $constraints) or Directory($storage, $constraints) constructor:

  • Constraint::IN_OPENBASEDIR => the path must be within the open_basedir php-ini paths, this allows throwing exceptions before running into php core errors
  • Constraint::DISALLOW_LINK => the path must not be a (symbolic-) link
  • Constraint::IN_SAFEPATH => if a file/directory path is build out of multiple components (parameters), the resulting file/directory destination must be inside the first path-component (called safepath)
use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;
use ricwein\FileSystem\Helper\Constraint;

// let's assume $_GET['file'] == '/../file.txt'

// path concatenated as a single string
// this runs fine but is HIGHLY UNRECOMMENDED
$file = new File(new Storage\Disk(__DIR__ . $_GET['file']));

// path is passed as single parameters (comma instead of dot!)
// this throws an error since the resulting path is not within __DIR__
$file = new File(new Storage\Disk(__DIR__, $_GET['file']));

// however: disabling the safepath-constraint wold also allow ../ path attacks:
$file = new File(new Storage\Disk(__DIR__, $_GET['file']), Constraint::STRICT & ~Constraint::IN_SAFEPATH);

Extensions

Directory Extensions

  • Directory\Command: Allows running shell-commands inside the given directory.
use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Helper\Constraint;
use ricwein\FileSystem\Storage;

$git = new Directory\Command(new Storage\Disk(__DIR__), Constraint::STRICT, ['/usr/local/bin/git', '/usr/bin/git']);
$ref = $git->execSafe('rev-parse HEAD');

File Extensions

  • File\Image: Allows image-manipulations based on imagemagick or gd (later one is default). Requires the Intervention\Image package.

Be aware: all image-file manipulations are directly mutating the original file!

use Intervention\Image\Image;
use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$image = new File\Image(new Storage\Disk('test.png'));
$image->resizeToFit(1024, 1024);
$image->compress(1048576); // iterative process to reduce filesize to be less than given filesize (1MB) by reducing the jpg-quality
// $image->encode('jpg');
$image->edit(function (Image $image): Image {
    // add advanced image-manipulation here
    [...]
    return $image;
});
  • File\Zip: Allows basic zip-operations, like creating a new archive or extracting an existing one.
use ricwein\FileSystem\Directory;
use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$zip = new File\Zip(new Storage\Disk('archive.zip'));

// create zip file
$zip->add(new File(new Storage\Disk('file.json'))); // or $zip->addFile(...)
$zip->add(new File(new Storage\Memory('some file-content')), 'anotherfile.txt'); // or $zip->addFile(...)
$zip->add(new Directory(new Storage\Disk(__DIR__, 'data-dir'))); // or $zip->addDirectory(...)
$zip->commit();

// extract zip file
$extractDir = $zip->extractTo(new Storage\Disk\Temp);

Storage Extensions

  • Disk\Current: Uses current-working-directory (getcwd()) as safepath. Useful for cli-scripts in combination with Directory\Command.
use ricwein\FileSystem\File;
use ricwein\FileSystem\Helper\Constraint;
use ricwein\FileSystem\Storage;

$current = new File(new Storage\Disk(getcwd(), 'file.json'), Constraint::STRICT & ~Constraint::IN_SAFEPATH);
// is the same as:
$current = new File(new Storage\Disk\Current('file.json'));
use ricwein\FileSystem\Directory;
use ricwein\FileSystem\Helper\Constraint;
use ricwein\FileSystem\Storage;

$git = new Directory\Command(new Storage\Disk\Current, Constraint::STRICT, ['/usr/local/bin/git', '/usr/bin/git']);

if (!$git->execSafe('pull $branch', ['branch' => 'develop'])) {
    echo 'failed to execute: ' . $git->getLastCommand() . PHP_EOL;
}

exit($git->lastExitCode());
  • Disk\Temp: Uses the system-temp directory to create a temporary file/directory. The file is automatically removed after freeing the object instance!
use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$temp = new File(new Storage\Disk\Temp);
$temp->write('test');
$temp->read();
$temp = null; // will delete the temp-file again!
  • Disk\Uploaded: Provides safe and easy uploaded-files access through php's native is_uploaded_file() and move_uploaded_file() functions.
use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$uploaded = new File(new Storage\Disk\Uploaded($_FILES['file']));
$file = $uploaded->moveTo(new Storage\Disk(__DIR__, 'uploads'));
  • Memory\Resource: Reads resource content into MEMORY on construction. The resource can be closed afterwards.

ATTENTION: Usually it's a better idea to just use Stream instead!

use ricwein\FileSystem\File;
use ricwein\FileSystem\Storage;

$resource = fopen('test.json', 'rb');
$file = new File(new Storage\Memory\Resource($resource));
fclose($resource);
$content = $file->read();