SwiftNIO Redis is a Swift package that contains a high performance Redis protocol implementation for SwiftNIO. This is a standalone project and has no other dependencies but SwiftNIO.
Apart from the protocol implementation which can encode and decode RESP (REdis Serialization Protocol), we also provide a Redis client module build on top.
What is Redis? Redis is a highly scalable in-memory data structure store, used as a database, cache and message broker. For example it can be used to implement a session store backing a web backend using its "expiring keys" feature, or it can be used as a relay to implement a chat server using its builtin PubSub features.
This Swift package includes the RESP protocol implementation. A simple Redis client can be found on swift-nio-redis-client. We also provide an actual Redis Server written in Swift, using SwiftNIO and SwiftNIO Redis.
This implementation is focused on performance.
It tries to reuse NIO ByteBuffer
s as much as possible to avoid copies.
The parser is based on a state machine, not on a buffering
ByteToMessageDecoder
/Encoder.
That doesn't make it nice, but efficient ;-)
An example Package.swift
importing the necessary modules:
// swift-tools-version:5.0
import PackageDescription
let package = Package(
name: "RedisTests",
dependencies: [
.package(url: "https://github.com/SwiftNIOExtras/swift-nio-redis.git",
from: "0.9.2")
],
targets: [
.target(name: "MyProtocolTool",
dependencies: [ "NIORedis" ])
]
)
The RESP protocol is implemented as a regular
ChannelHandler
, similar to NIOHTTP1
.
It takes incoming ByteBuffer
data, parses that, and emits RESPValue
items.
Same the other way around, the user writes RESPValue
(or RESPEncodable
)
objects, and the handler renders such into ByteBuffer
s.
The NIORedis module has a litte more information.
To add the RESP handler to a NIO Channel pipeline, the configureRedisPipeline
method is called, e.g.:
import NIORedis
bootstrap.channelInitializer { channel in
channel.pipeline
.configureRedisPipeline()
.then { ... }
}
The
protocol implementation
is considered complete. There are a few open ends
in the telnet
variant, yet the regular binary protocol is considered done.
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