# GraphQL Websocket Client
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An extensible client for connecting with GraphQL over Websockets following the
[graphql-ws](https://github.com/enisdenjo/graphql-ws) conventions.
## Installation
The package can be installed by adding `graphql_ws_client` to your list of
dependencies in `mix.exs`.
```elixir
def deps do
[
{:graphql_ws_client, "~> 1.0"},
]
end
```
If you are using the default configuration, `GraphQLWSClient.Drivers.Gun` is
used as driver and you will need the `gun` and `jason` packages as well.
```elixir
def deps do
[
# ...
{:gun, "~> 2.0"},
{:jason, "~> 1.4"},
]
end
```
Take a
look in the driver documentation to find out how to customize driver options.
Alternatively, you can write your own driver based on the
`GraphQLWSClient.Driver` behaviour.
## Usage
Connect to a socket:
```elixir
{:ok, socket} = GraphQLWSClient.start_link(url: "ws://localhost:4000/socket")
```
Send a query or mutation and return the result immediately:
```elixir
{:ok, result} = GraphQLWSClient.query(socket, "query GetPost { ... }")
```
Register a subscription to listen for events:
```elixir
{:ok, subscription_id} = GraphQLWSClient.subscribe(
socket,
"subscription PostCreated { ... }"
)
GraphQLWSClient.query!(socket, "mutation CreatePost { ... }")
receive do
%GraphQLWSClient.Event{type: :error, id: ^subscription_id, payload: error} ->
IO.inspect(error, label: "error")
%GraphQLWSClient.Event{type: :next, id: ^subscription_id, payload: result} ->
IO.inspect(result)
%GraphQLWSClient.Event{type: :complete, id: ^subscription_id} ->
IO.puts("Stream closed")
end
GraphQLClient.close(socket)
```
You would usually put this inside of a custom `GenServer` and handle the events
in `handle_info/3`.
Alternatively, you can create a stream of results:
```elixir
socket
|> GraphQLWSClient.stream!("subscription PostCreated { ... }")
|> Stream.each(fn result ->
IO.inspect(result)
end)
|> Stream.run()
```
## Custom Client
If you want to run the client as part of a supervision tree in your
application, you can also `use GraphQLWSClient` to create your own client.
```elixir
defmodule MyClient do
use GraphQLWSClient, otp_app: :my_app
end
```
Then, you can configure your client using a config file:
```elixir
import Config
config :my_app, MyClient,
url: "ws://localhost:4000/socket"
```
## Docs
Documentation can be found at <https://hexdocs.pm/graphql_ws_client> or
generated locally using `mix docs`.