https://github.com/d-exclaimation/pioneer-redis-pubsub

Pioneer's PubSub Implementation with Redis using RediStack
https://github.com/d-exclaimation/pioneer-redis-pubsub

graphql graphql-subscriptions pioneer pubsub redis swift

Last synced: about 2 months ago
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Pioneer's PubSub Implementation with Redis using RediStack

• Host: GitHub
• URL: https://github.com/d-exclaimation/pioneer-redis-pubsub
• Owner: d-exclaimation
• License: apache-2.0
• Created: 2022-06-26T10:23:33.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2023-10-22T08:20:23.000Z (about 1 year ago)
• Last Synced: 2023-10-23T04:34:11.044Z (about 1 year ago)
• Topics: graphql, graphql-subscriptions, pioneer, pubsub, redis, swift
• Language: Swift
• Homepage:
• Size: 46.9 KB
• Stars: 6
• Watchers: 1
• Forks: 2
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# PioneerRedisPubSub

This package implements the PubSub protocol from the [Pioneer](https://github.com/d-exclaimation/pioneer) package. It allows you to use a Redis-backed Pub/Sub with similar interface as the [AsyncPubSub](https://pioneer-graphql.netlify.app/guides/advanced/subscriptions/#asyncpubsub) and use it for your subscription resolvers.

## Setup

```swift

.package(url: "https://github.com/d-exclaimation/pioneer-redis-pubsub", from: "1.0.0")

```

## Usage

Create a RedisPubSub instance (Here is an example using [Vapor's Redis integration](https://docs.vapor.codes/redis/overview/)):

```swift

import Vapor

import Redis

import Pioneer

import PioneerRedisPubSub

let app = try Application(.detect())

app.redis.configuration = try RedisConfiguration(hostname: "localhost")

struct Resolver {

    let pubsub: PubSub = RedisPubSub(app.redis)

}

```

Now, implement your subscription resolver function, using the `pubsub.asyncStream` and call `.toEventStream()` to convert into an EventStream using [AsyncEventStream](https://pioneer-graphql.netlify.app/features/async-event-stream/)

Internally calling the method `.asyncStream` of the RedisPubSub will send redis a `SUBSCRIBE` message to the topic provided if there hasn't been a subscription for that topic.

```swift

import Graphiti

extension Resolver {

    var ON_MESSAGE: String {

        "some-redis-channel"

    }

    func somethingChanged(_: Context, _: NoArguments) -> EventStream {

        pubsub

            .asyncStream(Message.self, for: ON_MESSAGE)

            .toEventStream()

    }

}

```

RedisPubSub manages internally a collection of subscribers (using Actors) which can be individually unsubscribe without having to close all other subcriber of the same topic. Every time the `.publish` method is called, RedisPubSub will `PUBLISH` the event over redis which will be picked up by the RedisPubSub if there exist subscriber(s) for that topic.

Now, call `.publish` method whenever you want to push an event to the subscriber(s).

```swift

extension Resolver {

    func changeSomething(_: Context, args: SomeArgs) async -> Message {

        let message = Message(using: args)

        await pubsub.publish(for: ON_MESSAGE, payload: message)

        return message

    }

}

```

In cases where you no longer want push any message to any subscriber and/or consider a topic closed, you can call the `.close` method for a topic to shutdown all active subcribers for that topic and end the subscription operation.

```swift

extension Resolver {

    func closeSomething(_: Context, _: NoArguments) async -> Bool {

        await pubsub.close(for: ON_MESSAGE)

        return true

    }

}

```

> :warning: RedisPubSub itself does not automatically unsubscribed from any active channels except when `.close` is called, including when it has been disposed / deinitialized!

### More information

- [Pioneer](https://github.com/d-exclaimation/pioneer)

- [Pioneer's PubSub](https://pioneer-graphql.netlify.app/guides/advanced/subscriptions/#pubsub-as-protocol)

- [RediStack](https://gitlab.com/Mordil/RediStack/)