GraphQL Plug

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graphql_plug is a Plug integration for the GraphQL Elixir implementation of Facebook’s GraphQL.

Allows you to easily mount a GraphQL endpoint in Phoenix.

Installation

  1. Make a new Phoenix app

    mix phoenix.new hello_graphql --no-ecto
    cd hello_graphql
  2. Add plug_graphql to your list of dependencies in mix.exs and install the package with mix deps.get.

    def deps do
      [{:plug_graphql, "~> 0.0.2"}]
    end

Usage

  1. Define a Schema. Here’s a simple one to try out:

    # The GraphQL schema we're going to use
    defmodule TestSchema do
      def schema do
        %GraphQL.Schema{
          query: %GraphQL.ObjectType{
            name: "RootQueryType",
            fields: [
              %GraphQL.FieldDefinition{
                name: "greeting",
                type: "String",
                resolve: &TestSchema.greeting/1,
              }
            ]
          }
        }
      end
    
      def greeting(name: name), do: "Hello, #{name}!"
      def greeting(_), do: greeting(name: "world")
    end
  2. Add the plug to your api pipeline:

    pipeline :api do
      plug :accepts, ["json"]
    
      plug GraphQL.Plug.GraphQLEndpoint, TestSchema.schema
    end
  3. Add an endpoint so this route fires

    scope "/api", HelloGraphql do
      pipe_through :api
      get "/", PageController, :index
    end
  4. Start Phoenix

    mix phoenix.server
  5. Open your browser to http://localhost:4000/api?query={greeting} and you should see something like this:

    {
      "data": {
        "greeting": "Hello, world!"
      }
    }

Contributions

This is pretty early days, the graphql execution engine needs a lot more work to be useful.

However we can’t get there without your help, so any questions, bug reports, feedback, feature requests and/or PRs are most welcome!