GraphQL for .NET

This is a work-in-progress implementation of Facebook's GraphQL in .NET.

This project uses a lexer/parser originally written by Marek Magdziak and released with a MIT license. Thank you Marek!

Installation

You can install the latest version via NuGet.

PM> Install-Package GraphQL

Upgrade Guide

• 0.11.0
• 0.8.0

GraphiQL

There is a sample web api project hosting the GraphiQL interface. yarn install and yarn start from the root of the repository, then run the web project from Visual Studio.

Note: Before running the GraphiQL project: make sure you Build the entire solution so that all the project references get built. (GraphQL, GraphQL-Parser, etc) to avoid missing reference/assembly errors.

> npm install -g yarn
> yarn install
> yarn start

Usage

Define your schema with a top level query object then execute that query.

A more full-featured example including all classes required can be found here.

namespace ConsoleApplication
{
    using System;
    using System.Threading.Tasks;
    using GraphQL;
    using GraphQL.Http;
    using GraphQL.Types;

    public class Program
    {
        public static void Main(string[] args)
        {
          Run();
        }

        private static async void Run()
        {
          Console.WriteLine("Hello GraphQL!");

          var schema = new Schema { Query = new StarWarsQuery() };

          var result = await new DocumentExecuter().ExecuteAsync( _ =>
          {
            _.Schema = schema;
            _.Query = @"
                query {
                  hero {
                    id
                    name
                  }
                }
              ";
          }).ConfigureAwait(false);

          var json = new DocumentWriter(indent: true).Write(result);

          Console.WriteLine(json);
        }
    }

    public class Droid
    {
      public string Id { get; set; }
      public string Name { get; set; }
    }

    public class DroidType : ObjectGraphType<Droid>
    {
      public DroidType()
      {
        Field(x => x.Id).Description("The Id of the Droid.");
        Field(x => x.Name, nullable: true).Description("The name of the Droid.");
      }
    }

    public class StarWarsQuery : ObjectGraphType
    {
      public StarWarsQuery()
      {
        Field<DroidType>(
          "hero",
          resolve: context => new Droid { Id = "1", Name = "R2-D2" }
        );
      }
    }
}

Output

Hello GraphQL!
{
  "data": {
    "hero": {
      "id": "1",
      "name": "R2-D2"
    }
  }
}

Roadmap

Grammar / AST

• Grammar and AST for the GraphQL language should be compatible with the April 2016 specification.

Operation Execution

• Scalars
• Objects
• Lists of objects/interfaces
• Interfaces
• Unions
• Arguments
• Variables
• Fragments
• Directives
  • Include
  • Skip
  • Custom
• Enumerations
• Input Objects
• Mutations
• Subscriptions
• Async execution

Validation

• Arguments of correct type
• Default values of correct type
• Fields on correct type
• Fragments on composite types
• Known argument names
• Known directives
• Known fragment names
• Known type names
• Lone anonymous operations
• No fragment cycles
• No undefined variables
• No unused fragments
• No unused variables
• Overlapping fields can be merged
• Possible fragment spreads
• Provide non-null arguments
• Scalar leafs
• Unique argument names
• Unique directives per location
• Unique fragment names
• Unique input field names
• Unique operation names
• Unique variable names
• Variables are input types
• Variables in allowed position

Schema Introspection

• __typename
• __type
  • name
  • kind
  • description
  • fields
  • interfaces
  • possibleTypes
  • enumValues
  • inputFields
  • ofType
• __schema
  • types
  • queryType
  • mutationType
  • subscriptionType
  • directives

Deployment Process

yarn run setVersion 0.12.0
write release notes in release-notes.md
git commit/push
download nuget from AppVeyor
upload nuget package to github
publish nuget from MyGet