https://github.com/krisleech/evented
Publish and Subscribe for Crystal objects
https://github.com/krisleech/evented
Last synced: about 1 year ago
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Publish and Subscribe for Crystal objects
- Host: GitHub
- URL: https://github.com/krisleech/evented
- Owner: krisleech
- License: mit
- Created: 2015-07-29T21:23:08.000Z (almost 11 years ago)
- Default Branch: master
- Last Pushed: 2018-01-26T11:02:25.000Z (over 8 years ago)
- Last Synced: 2025-04-13T03:06:52.652Z (about 1 year ago)
- Language: Crystal
- Size: 8.79 KB
- Stars: 34
- Watchers: 4
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Evented
*A micro library providing Crystal objects with Publish-Subscribe capabilities*
[](https://travis-ci.org/krisleech/evented)
* Decouple core business logic from external concerns in Hexagonal style architectures
* Use as an alternative to callbacks and Observers
* Connect objects based on context without permanence
* React to events synchronously
## Installation
Add this to your application's `shard.yml`:
```yaml
dependencies:
evented:
github: krisleech/evented
```
## Usage
### Publishing
By including `Evented::Publisher` your objects get `broadcast` and
`subscribe` methods.
`broadcast` can be called from within your object whenever you want to
broadcast a significant event.
```crystal
require "evented"
class MyPublisher
include Evented::Publisher
def call(input)
result = do_something(input)
broadcast(:something_happened, result)
end
end
```
### Subscribing
To subscribe an object to receive events include `Evented::Subscriber` and
provide your own `on_event` method which will receive 2 arguments, the
`event_name` and `payload`.
```crystal
require "evented"
class MySubscriber
include Evented::Subscriber
def on_event(event_name, payload)
# ...
end
end
```
To subscribe the listener to a publisher:
```crystal
publisher = MyPublisher.new
publisher.subscribe(MySubscriber.new)
publisher.call("hello")
```
In the above example the subscriber will have `on_event(:something_happened, "hello")`
called.
## Development
### Specs
```
crystal spec
```
### Automatically run Specs
```
ls ./**/*.cr | entr crystal spec
```
## Contributing
1. Fork it ( https://github.com/krisleech/evented/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request
## Contributors
- [Kris Leech](https://github.com/krisleech) - creator, maintainer