# Absinthe.Relay

Support for the [Relay framework](https://facebook.github.io/relay/)
from Elixir, using the [Absinthe](https://github.com/absinthe-graphql/absinthe)
package.

Please note that this is the initial release of this package and that
significant API changes are expected before v1.0.

## Installation

Install from [Hex.pm](https://hex.pm/packages/absinthe_relay):

```elixir
def deps do
  [{:absinthe_relay, "~> 1.2.0-alpha0"}]
end
```

Add it to your `applications` configuration in `mix.exs`, too:

```elixir
def application do
  [applications: [:absinthe_relay]]
end
```

Note: Absinthe requires Elixir 1.3 or higher.

## Upgrading

See [CHANGELOG](./CHANGELOG.md) for upgrade steps between versions.

## Documentation

See "Usage," below, for basic usage information and links to specific resources.

- For the tutorial, guides, and general information about Absinthe-related
  projects, see [http://absinthe-graphql.org](http://absinthe-graphql.org).
- Links to the API documentation are available in the [project list](http://absinthe-graphql.org/projects).

### Roadmap

See the Roadmap on [absinthe-graphql.org](http://absinthe-graphql.org/roadmap).

## Related Projects

See the Project List on [absinthe-graphql.org](http://absinthe-graphql.org/projects).

## Usage

Schemas should `use Absinthe.Relay.Schema`, eg:

```elixir
defmodule Schema do
  use Absinthe.Schema
  use Absinthe.Relay.Schema

  # ...

end
```

For a type module, use `Absinthe.Relay.Schema.Notation`

```elixir
defmodule Schema do
  use Absinthe.Schema.Notation
  use Absinthe.Relay.Schema.Notation

  # ...

end
```

See the documentation for [Absinthe.Relay.Node](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Node.html),
[Absinthe.Relay.Connection](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Connection.html), and [Absinthe.Relay.Mutation](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Mutation.html)  for
specific usage information.

### Node Interface

Relay
[requires an interface](https://facebook.github.io/relay/docs/graphql-object-identification.html),
`"Node"`, be defined in your schema to provide a simple way to fetch
objects using a global ID scheme.

See the [Absinthe.Relay.Node](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Node.html)
module documentation for specific instructions on how do design a schema that makes use of nodes.

### Connection

Relay uses
[Connection](http://facebook.github.io/relay/docs/graphql-connections.html)
(and other related) types to provide a standardized way of slicing and
paginating a one-to-many relationship.

Support in this package is designed to match the [Relay Cursor Connection Specification](http://facebook.github.io/relay/graphql/connections.htm).

See the [Absinthe.Relay.Connection](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Connection.html)
module documentation for specific instructions on how do design a schema that makes use of nodes.

### Mutation

Relay supports mutation via [a contract](https://facebook.github.io/relay/docs/graphql-mutations.html) involving single input object arguments with and client mutation
IDs.

Support in this package is designed to match the [Relay Input Object Mutations Specification](https://facebook.github.io/relay/graphql/mutations.htm).

See the [Absinthe.Relay.Mutation](https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Mutation.html) module documentation for specific instructions on how to design a schema that makes use of mutations.

## Supporting the Babel Relay Plugin

To generate a `schema.json` file for use with the [Babel Relay Plugin](https://facebook.github.io/relay/docs/guides-babel-plugin.html#schema-json), run the `absinthe.schema.json` Mix task, built-in to [Absinthe](https://github.com/absinthe-graphql/absinthe).

In your project, check out the documentation with:

```
mix help absinthe.schema.json
```

## License

BSD License

Copyright (c) CargoSense, Inc.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice, this
   list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * Neither the name Facebook nor the names of its contributors may be used to
   endorse or promote products derived from this software without specific
   prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.