This is a maintenance release for the 0.8 series with some improvements to existing features. What follows is an overview of the changes and bug fixes introduced in this new release, details are also available in the CHANGELOG.
New features
Redis commands
- Added a new server profile for Redis 2.8. The default value for the
profileclient option still targets Redis 2.6 and thedevprofile now targets Redis 3.0. - New commands added to the
2.8profile:SCAN,SSCAN,ZSCANandHSCANto the server profile for Redis 2.8.
Collection iterators
The new cursor-based iterator commands available starting from Redis 2.8 make it possible to iterate Redis collections without blocking the server but developers still need to implement some logic in their applications to fully leverage them. To ease the usage of such commands we added some abstractions in the Predis\Collection namespace in the form of plain old PHP iterators, making it possible to fully iterate Redis collections in your PHP code with something as simple as foreach.
- Keyspace iterator:
Predis\Collection\Iterator\Keyspacebased onSCAN. - Set iterator:
Predis\Collection\Iterator\SetKeybased onSSCAN. - Sorted set iterator:
Predis\Collection\Iterator\SortedSetKeybased onZSSCAN. - Hash iterator:
Predis\Collection\Iterator\HashKeybased onHSCAN.
Redis do not have a cursor-based iterator for lists but we added an abstraction with Predis\Collection\Iterator\ListKey based on LRANGE that tries to mimic a similar behavior while not being exactly the same thing.
You can find some examples here.
Raw commands
It is possible to execute raw commands using Predis\Command\RawCommand and a variable list of command arguments. The main difference with the usual approach is that input arguments are not filtered and complex responses are not parsed, which also means arguments must follow the exact same signature of the command as defined by Redis. Obviously there is no need to create and register a new class to use them:
$command = Predis\Command\RawCommand::create('SET', 'foo', 'bar');
$response = $client->executeCommand($command);Executing commands in this way can be useful to implement internal features, when the user-specified server profile is not accessible or when you need to make sure that your code will not be affected by different argument filtering or response parsing implementations.
This feature will be further improved in the next major release.
Improvements
Redis Cluster
Some aspects of our abstraction for Redis Cluster have been dramatically improved or fixed while others (such as silent handling of connection failures) will be addressed in later patch releases.
- The
ASKINGcommand is now correctly sent automatically upon-ASKredirections. - Updated slots maps can be fetched from nodes thanks to the
CLUSTER NODEScommand. By default this is a manual operation but it can be enabled to get automatically done upon-MOVEDredirections. - It is possible to specify a common set of connection parameters that are applied to connections created on the fly upon redirections to nodes that are not part of the initial pool.
Query string parsing for connection parameters
URI parsing now relies on parse_str for the query string part which has a slightly smaller overhead when the number of fields in the querystring grows. Furthermore:
- Parsing does not break when value of a field contains one or more
=. - Repeated fieldnames using
[]produce an array of values. - Empty or incomplete
key=valuepairs result in an empty string forkey.
Deprecations
A couple of methods of Predis\Client are now marked as deprecated and will be removed in the next major release:
Predis\Client::multiExec(): superseded byPredis\Client::transaction().Predis\Client::pubSub(): superseded byPredis\Client::pubSubLoop(). This change was needed due to the recently introducedPUBSUBcommand in Redis 2.8.
Future development
Aside from a few more tweaks aimed at improving support for the upcoming Redis Cluster there is not much to add or change in the current v0.8 branch. The library is very stable judging by the history of issues opened during the last months so you can expect a couple of patch releases for v0.8 until Redis 3.0 but nothing more. The good news is that the release of the next major version is imminent and Predis will finally hit v1.0! The transition from v0.8 to v1.0 will bring a lot of breaking changes required to polish the API of the library and its internals, but the actual impact on your code (that is, if you plan to upgrade) may vary depending on your kind of usage: in simple scenarios where Predis is used as a mere client without relying on its extensibility, it is pretty much possible that nothing will change for you.
You can already start playing with it by requiring "predis/predis": "dev-master" in composer.json. Predis v1.0.0 is planned to be released on the same day of the first beta of Redis Cluster, 10th February 2014.