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clue/reactphp-redis

Async Redis client implementation, built on top of ReactPHP.

Development version: This branch contains the code for the upcoming 3.0 release. For the code of the current stable 2.x release, check out the 2.x branch.

The upcoming 3.0 release will be the way forward for this package. However, we will still actively support 2.x for those not yet on the latest version. See also installation instructions for more details.

Redis is an open source, advanced, in-memory key-value database. It offers a set of simple, atomic operations in order to work with its primitive data types. Its lightweight design and fast operation makes it an ideal candidate for modern application stacks. This library provides you a simple API to work with your Redis database from within PHP. It enables you to set and query its data or use its PubSub topics to react to incoming events.

• Async execution of Commands - Send any number of commands to Redis in parallel (automatic pipeline) and process their responses as soon as results come in. The Promise-based design provides a sane interface to working with async responses.
• Event-driven core - Register your event handler callbacks to react to incoming events, such as an incoming PubSub message event.
• Lightweight, SOLID design - Provides a thin abstraction that is just good enough and does not get in your way. Future or custom commands and events require no changes to be supported.
• Good test coverage - Comes with an automated tests suite and is regularly tested against versions as old as Redis v2.6 and newer.

Table of Contents

• Support us
• Quickstart example
• Usage
  • Commands
  • Promises
  • PubSub
• API
  • RedisClient
    • __construct()
    • __call()
    • end()
    • close()
    • error event
    • close event
• Install
• Tests
• License

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Quickstart example

Once installed, you can use the following code to connect to your local Redis server and send some requests:

See also the examples.

Usage

Commands

Most importantly, this project provides a RedisClient instance that can be used to invoke all Redis commands (such as GET, SET, etc.).

Each method call matches the respective Redis command. For example, the $redis->get() method will invoke the GET command.

All Redis commands are automatically available as public methods via the magic __call() method. Listing all available commands is out of scope here, please refer to the Redis command reference.

Any arguments passed to the method call will be forwarded as command arguments. For example, the $redis->set('name', 'Alice') call will perform the equivalent of a SET name Alice command. It's safe to pass integer arguments where applicable (for example $redis->expire($key, 60)), but internally Redis requires all arguments to always be coerced to string values.

Each of these commands supports async operation and returns a Promise that eventually fulfills with its results on success or rejects with an Exception on error. See also the following section about promises for more details.

Promises

Sending commands is async (non-blocking), so you can actually send multiple commands in parallel. Redis will respond to each command request with a response message, pending commands will be pipelined automatically.

Sending commands uses a Promise-based interface that makes it easy to react to when a command is completed (i.e. either successfully fulfilled or rejected with an error):

PubSub

This library is commonly used to efficiently transport messages using Redis' Pub/Sub (Publish/Subscribe) channels. For instance, this can be used to distribute single messages to a larger number of subscribers (think horizontal scaling for chat-like applications) or as an efficient message transport in distributed systems (microservice architecture).

The PUBLISH command can be used to send a message to all clients currently subscribed to a given channel:

The SUBSCRIBE command can be used to subscribe to a channel and then receive incoming PubSub message events:

Likewise, you can use the same client connection to subscribe to multiple channels by simply executing this command multiple times:

Similarly, the PSUBSCRIBE command can be used to subscribe to all channels matching a given pattern and then receive all incoming PubSub messages with the pmessage event:

Once you're in a subscribed state, Redis no longer allows executing any other commands on the same client connection. This is commonly worked around by simply creating a second client connection and dedicating one client connection solely for PubSub subscriptions and the other for all other commands.

The UNSUBSCRIBE command and PUNSUBSCRIBE command can be used to unsubscribe from active subscriptions if you're no longer interested in receiving any further events for the given channel and pattern subscriptions respectively:

Likewise, once you've unsubscribed the last channel and pattern, the client connection is no longer in a subscribed state and you can issue any other command over this client connection again.

Each of the above methods follows normal request-response semantics and return a Promise to await successful subscriptions. Note that while Redis allows a variable number of arguments for each of these commands, this library is currently limited to single arguments for each of these methods in order to match exactly one response to each command request. As an alternative, the methods can simply be invoked multiple times with one argument each.

Additionally, can listen for the following PubSub events to get notifications about subscribed/unsubscribed channels and patterns:

When the underlying connection is lost, the unsubscribe and punsubscribe events will be invoked automatically. This gives you control over re-subscribing to the channels and patterns as appropriate.

API

RedisClient

The RedisClient is responsible for exchanging messages with your Redis server and keeps track of pending commands.

Besides defining a few methods, this interface also implements the EventEmitterInterface which allows you to react to certain events as documented below.

Internally, this class creates the underlying connection to Redis only on demand once the first request is invoked on this instance and will queue all outstanding requests until the underlying connection is ready. This underlying connection will be reused for all requests until it is closed. By default, idle connections will be held open for 1ms (0.001s) when not used. The next request will either reuse the existing connection or will automatically create a new underlying connection if this idle time is expired.

From a consumer side this means that you can start sending commands to the database right away while the underlying connection may still be outstanding. Because creating this underlying connection may take some time, it will enqueue all outstanding commands and will ensure that all commands will be executed in correct order once the connection is ready.

If the underlying database connection fails, it will reject all outstanding commands and will return to the initial "idle" state. This means that you can keep sending additional commands at a later time which will again try to open a new underlying connection. Note that this may require special care if you're using transactions (MULTI/EXEC) that are kept open for longer than the idle period.

While using PubSub channels (see SUBSCRIBE and PSUBSCRIBE commands), this client will never reach an "idle" state and will keep pending forever (or until the underlying database connection is lost). Additionally, if the underlying database connection drops, it will automatically send the appropriate unsubscribe and punsubscribe events for all currently active channel and pattern subscriptions. This allows you to react to these events and restore your subscriptions by creating a new underlying connection repeating the above commands again.

Note that creating the underlying connection will be deferred until the first request is invoked. Accordingly, any eventual connection issues will be detected once this instance is first used. You can use the end() method to ensure that the connection will be soft-closed and no further commands can be enqueued. Similarly, calling end() on this instance when not currently connected will succeed immediately and will not have to wait for an actual underlying connection.

__construct()

The new RedisClient(string $url, ConnectorInterface $connector = null, LoopInterface $loop = null) constructor can be used to create a new RedisClient instance.

The $url can be given in the standard form [redis[s]://][:auth@]host[:port][/db]. You can omit the URI scheme and port if you're connecting to the default port 6379:

Redis supports password-based authentication (AUTH command). Note that Redis' authentication mechanism does not employ a username, so you can pass the password h@llo URL-encoded (percent-encoded) as part of the URI like this:

You can optionally include a path that will be used to select (SELECT command) the right database:

You can use the standard rediss:// URI scheme if you're using a secure TLS proxy in front of Redis:

You can use the redis+unix:// URI scheme if your Redis instance is listening on a Unix domain socket (UDS) path:

This method respects PHP's default_socket_timeout setting (default 60s) as a timeout for establishing the underlying connection and waiting for successful authentication. You can explicitly pass a custom timeout value in seconds (or use a negative number to not apply a timeout) like this:

By default, idle connections will be held open for 1ms (0.001s) when not used. The next request will either reuse the existing connection or will automatically create a new underlying connection if this idle time is expired. This ensures you always get a "fresh" connection and as such should not be confused with a "keepalive" or "heartbeat" mechanism, as this will not actively try to probe the connection. You can explicitly pass a custom idle timeout value in seconds (or use a negative number to not apply a timeout) like this:

If you need custom DNS, proxy or TLS settings, you can explicitly pass a custom instance of the ConnectorInterface:

__call()

The __call(string $name, string[] $args): PromiseInterface<mixed> method can be used to invoke the given command.

This is a magic method that will be invoked when calling any Redis command on this instance. Each method call matches the respective Redis command. For example, the $redis->get() method will invoke the GET command.

All Redis commands are automatically available as public methods via this magic __call() method. Listing all available commands is out of scope here, please refer to the Redis command reference.

Any arguments passed to the method call will be forwarded as command arguments. For example, the $redis->set('name', 'Alice') call will perform the equivalent of a SET name Alice command. It's safe to pass integer arguments where applicable (for example $redis->expire($key, 60)), but internally Redis requires all arguments to always be coerced to string values.

Each of these commands supports async operation and returns a Promise that eventually fulfills with its results on success or rejects with an Exception on error. See also promises for more details.

end()

The end():void method can be used to soft-close the Redis connection once all pending commands are completed.

close()

The close():void method can be used to force-close the Redis connection and reject all pending commands.

error event

The error event will be emitted once a fatal error occurs, such as when the client connection is lost or is invalid. The event receives a single Exception argument for the error instance.

This event will only be triggered for fatal errors and will be followed by closing the client connection. It is not to be confused with "soft" errors caused by invalid commands.

close event

The close event will be emitted once the client connection closes (terminates).

See also the close() method.

Install

The recommended way to install this library is through Composer. New to Composer?

Once released, this project will follow SemVer. At the moment, this will install the latest development version:

See also the CHANGELOG for details about version upgrades.

This project aims to run on any platform and thus does not require any PHP extensions and supports running on PHP 7.1 through current PHP 8+. It's highly recommended to use the latest supported PHP version for this project.

We're committed to providing long-term support (LTS) options and to provide a smooth upgrade path. You may target multiple versions at the same time to support a wider range of PHP versions like this:

Tests

To run the test suite, you first need to clone this repo and then install all dependencies through Composer:

To run the test suite, go to the project root and run:

The test suite is set up to always ensure 100% code coverage across all supported environments. If you have the Xdebug extension installed, you can also generate a code coverage report locally like this:

The test suite contains both unit tests and functional integration tests. The functional tests require access to a running Redis server instance and will be skipped by default.

If you don't have access to a running Redis server, you can also use a temporary Redis Docker image:

To now run the functional tests, you need to supply your login details in an environment variable like this:

On top of this, we use PHPStan on max level to ensure type safety across the project:

License

This project is released under the permissive MIT license.

Did you know that I offer custom development services and issuing invoices for sponsorships of releases and for contributions? Contact me (@clue) for details.