## Using Phar Archives: the Phar and PharData class

The Phar class supports reading and manipulation of Phar archives, as well as iteration through inherited functionality of the RecursiveDirectoryIterator class. With support for the ArrayAccess interface, files inside a Phar archive can be accessed as if they were part of an associative array.

The PharData class extends the Phar, and allows creating and modifying non-executable (data) tar and zip archives even if `phar.readonly`=1 in php.ini. As such, PharData::setAlias() and PharData::setStub() are both disabled as the concept of alias and stub are unique to executable phar archives.

It is important to note that when creating a Phar archive, the full path should be passed to the Phar object constructor. Relative paths will fail to initialize.

Assuming that `$p` is a Phar object initialized as follows:

`<?php
$p = new Phar('/path/to/myphar.phar', 0, 'myphar.phar');
?>`

An empty Phar archive will be created at `/path/to/myphar.phar`, or if `/path/to/myphar.phar` already exists, it will be opened again. The literal `myphar.phar` demonstrates the concept of an alias that can be used to reference `/path/to/myphar.phar` in URLs as in:

`<?php
// these two calls to file_get_contents() are equivalent if
// /path/to/myphar.phar has an explicit alias of "myphar.phar"
// in its manifest, or if the phar was initialized with the
// previous example's Phar object setup
$f = file_get_contents('phar:///path/to/myphar.phar/whatever.txt');
$f = file_get_contents('phar://myphar.phar/whatever.txt');
?>`

With the newly created `$p` Phar object, the following is possible:

- `$a = $p['file.php']` creates a PharFileInfo class that refers to the contents of `phar://myphar.phar/file.php`
- `$p['file.php'] = $v` creates a new file (`phar://myphar.phar/file.php`), or overwrites an existing file within `myphar.phar`. `$v` can be either a string or an open file pointer, in which case the entire contents of the file will be used to create the new file. Note that `$p->addFromString('file.php', $v)` is functionally equivalent to the above. Also possible is to add the contents of a file with `$p->addFile('/path/to/file.php', 'file.php')`. Lastly, an empty directory can be created with `$p->addEmptyDir('empty')`.
- `isset($p['file.php'])` can be used to determine whether `phar://myphar.phar/file.php` exists within `myphar.phar`.
- `unset($p['file.php'])` erases `phar://myphar.phar/file.php` from `myphar.phar`.

In addition, the Phar object is the only way to access Phar-specific metadata, through Phar::getMetadata(), and the only way to set or retrieve a Phar archive's PHP loader stub through Phar::getStub() and Phar::setStub(). Additionally, compression for the entire Phar archive at once can only be manipulated using the Phar class.

The full list of Phar object functionality is documented below.

The PharFileInfo class extends the SplFileInfo class, and adds several methods for manipulating Phar-specific details of a file contained within a Phar, such as manipulating compression and metadata.