# Ecto Observable
[](https://travis-ci.org/nsweeting/ecto_observable)
[](https://hex.pm/packages/ecto_observable)
Ecto Observable adds "observable" functionality to `Ecto.Repo`.
## Installation
The package can be installed by adding `ecto_observable` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:ecto_observable, "~> 0.4"}
]
end
```
## Documentation
See [HexDocs](https://hexdocs.pm/ecto_observable) for detailed documentation.
## Example
To get started we must add observability to our repo:
```elixir
defmodule Repo do
use Ecto.Repo, otp_app: :my_app
use Observable.Repo
end
```
We can now create an observer:
```elixir
defmodule SubscribersObserver do
use Observable, :observer
# Lets ignore posts that dont have any topics.
def handle_notify(:insert, {_repo, _old, %Post{topics: []}}) do
:ok
end
def handle_notify(:insert, {_repo, _old, %Post{topics: topics}}) do
# Do work required to inform subscribed users.
end
# Defined for the sake of example. Ignore me!
def handle_notify(:update, {_repo, old, new}) do
:ok
end
# Defined for the sake of example. Ignore me!
def handle_notify(:delete, {_repo, old, new}) do
:ok
end
end
```
And modify our `Post` schema to notify our observer:
```elixir
defmodule Post do
use Ecto.Schema
use Observable, :notifier
schema "posts" do
field(:title, :string)
field(:body, :string)
field(:topics, {:array, :string}, default: [])
end
observations do
action(:insert, [SubscribersObserver])
action(:update, [SubscribersObserver])
action(:delete, [OtherObserverOne, OtherObserverTwo]) # Defined for the sake of example.
end
end
```
Which allows us to use the notify functionality:
```elixir
def create_post(params \\ %{}) do
%Post{}
|> Post.changeset(params)
|> Repo.insert_and_notify()
end
```
Please see the [documentation](https://hexdocs.pm/ecto_observable) for more details.
