Stash Redis Driver

This is a RedisDriver for the PHP Caching Library Stash.

The original driver included in the project has 2 problems that are solved with this driver:

• When deleting the stackparent of a key the subkeys are also actively deleted. This happens in a semi-atomic way. That means that as long as the operation does not fail halfway through you can assume that all data has been removed.

• The keys that are being generated use a standard Redis pattern and are more easily identifiable than the current normalized keys which are hashed.

  In practice this means that it /test/key/with/stack/groups/ will be converted to test:key:with:stack:groups. If you decide to delete the stackparent /test/key and reinsert the first key it will be saved as test:key_1:with:stack:groups and all the keys with the previous structure will be deleted.

Another reason for making this repository instead of adding it to the project itself is that I believe a package should always explicitly specify it's dependencies.

Therefore the Drivers (which depend on third party software) should be in seperate repositories that clearly state their dependency and should inversely depend on the library in order to decouple them.

Unsupported Features

Multiple Servers

In contrast to the original Redis Driver from the Stash project this driver does not support multiple servers. To keep the interface similar to the other drivers the configuration key is still called servers though.

Example:

<?php
		$options = [
			'servers' => [
				['127.0.0.1', 6379],
			],
		];
		$driver  = new ResponStash\Driver\Redis($options);
		
		$this->stashPool = new \Stash\Pool($driver);

Note Multiple server support could be added by using Predis instead of PHPRedis since it supports actual clustering instead of \RedisArray. If you want this I'm looking forward to the PR.

Extra Options

This package adds the following options

normalize_keys

default value: true

Note If set to false it is illegal to use : and _ as part of your keys. Just define them as /part/of/a/nice/key/ without using underscores and you'll be fine.

If set to true all the parts of the keys will be normalized with the default Stash key normalization strategy. In practice this means that all the parts will be converted to md5 hashes. Warning: This may result in pretty long keys, a more intelligent normalization strategy might be required in those cases.