GraphQL 'Star Wars' example using GraphQL for .NET, ASP.NET Core, Entity Framework Core

Examples

• Basic - simple 'Hello GraphQL!' example based on console version from GraphQL for .NET on GitHub, but using ASP.NET Core, Entity Framework Core and some best practices, patterns and principles.

• Advanced - GraphQL queries and mutations with full 'Star Wars' database (see GraphQL Specification by Facebook and GraphQL.js - reference implementation)

Roadmap

• [x] Basic
  • [x] Simple tutorial (step/screenshot/code)
  • [ ] Detailed tutorial (steps explanation)
  • [x] 3-Layers (Api, Core, Data) architecture
  • [x] DDD (Domain Driven Design) hexagonal architecture
  • [x] Dependency Inversion (deafult ASP.NET Core IoC container)
  • [x] GraphQL controller
  • [x] In Memory 'Droid' Repository
  • [x] Entity Framework 'Droid' Repository
  • [x] Automatic database creation
  • [x] Seed database data
  • [x] EF Migrations
  • [x] GraphiQL
  • [x] Unit Tests
  • [x] Visual Studio 2017 RC upgrade
  • [x] Integration Tests
  • [x] Logs
  • [x] Code Coverage
  • [x] Continous Integration
• [ ] Advanced
  • [x] Full 'Star Wars' database (Episodes, Characters, Planets, Humans etc.)
  • [x] Base/generic repository
  • [x] Visual Studio 2017 RTM upgrade
  • [x] Repositories
  • [ ] GraphQL queries
  • [ ] GraphQL mutations
  • [ ] Docker
• [ ] PWA (Progressive Web App)
  • [ ] Identity microservice
  • [ ] Angular frontend
  • [ ] Apollo GraphQL Client for Angular
  • [ ] Service Worker
  • [ ] IndexedDB
  • ...

Tutorials

Basic

• Create 'StarWars' empty solution

• Add 'ASP.NET Core Web Application (.NET Core)' project named 'StarWars.Api'

• Select Web API template

• Update all NuGet packages

• Update project.json with correct runtime

"runtimes": {
   "win10-x64": { }
}

• Install GraphQL NuGet package

• Create 'StarWars.Core' project

• Create 'Droid' model

namespace StarWars.Core.Models
{
    public class Droid
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}

• Create 'DroidType' model

using GraphQL.Types;
using StarWars.Core.Models;

namespace StarWars.Api.Models
{
    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.");
        }
    }
}

• Create 'StarWarsQuery' model

using GraphQL.Types;
using StarWars.Core.Models;

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

• Create 'GraphQLQuery' model

namespace StarWars.Api.Models
{
    public class GraphQLQuery
    {
        public string OperationName { get; set; }
        public string NamedQuery { get; set; }
        public string Query { get; set; }
        public string Variables { get; set; }
    }
}

• Create 'GraphQLController'

using GraphQL;
using GraphQL.Types;
using Microsoft.AspNetCore.Mvc;
using StarWars.Api.Models;
using System.Threading.Tasks;

namespace StarWars.Api.Controllers
{
    [Route("graphql")]
    public class GraphQLController : Controller
    {
        [HttpPost]
        public async Task<IActionResult> Post([FromBody] GraphQLQuery query)
        {
            var schema = new Schema { Query = new StarWarsQuery() };

            var result = await new DocumentExecuter().ExecuteAsync(_ =>
            {
                _.Schema = schema;
                _.Query = query.Query;

            }).ConfigureAwait(false);

            if (result.Errors?.Count > 0)
            {
                return BadRequest();
            }

            return Ok(result);
        }
    }
}

• Test using Postman

• Create 'IDroidRepository' interface

using StarWars.Core.Models;
using System.Threading.Tasks;

namespace StarWars.Core.Data
{
    public interface IDroidRepository
    {
        Task<Droid> Get(int id);
    }
}

• Create 'StarWars.Data' project

• Create in memory 'DroidRepository'

using StarWars.Core.Data;
using System.Collections.Generic;
using System.Threading.Tasks;
using StarWars.Core.Models;
using System.Linq;

namespace StarWars.Data.InMemory
{
    public class DroidRepository : IDroidRepository
    {
        private List<Droid> _droids = new List<Droid> {
            new Droid { Id = 1, Name = "R2-D2" }
        };

        public Task<Droid> Get(int id)
        {
            return Task.FromResult(_droids.FirstOrDefault(droid => droid.Id == id));
        }
    }
}

• Use 'IDroidRepository' in StarWarsQuery

using GraphQL.Types;
using StarWars.Core.Data;

namespace StarWars.Api.Models
{
    public class StarWarsQuery : ObjectGraphType
    {
        private IDroidRepository _droidRepository { get; set; }

        public StarWarsQuery(IDroidRepository _droidRepository)
        {
            Field<DroidType>(
              "hero",
              resolve: context => _droidRepository.Get(1)
            );
        }
    }
}

• Update creation of StarWarsQuery in GraphQLController

// ...
public async Task<IActionResult> Post([FromBody] GraphQLQuery query)
{
    var schema = new Schema { Query = new StarWarsQuery(new DroidRepository()) };
// ...

• Test using Postman

• Configure dependency injection in Startup.cs

// ...
public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc();

    services.AddTransient<StarWarsQuery>();
    services.AddTransient<IDroidRepository, DroidRepository>();
}
// ...

• Use constructor injection of StarWarsQuery in GraphQLController

// ...
public class GraphQLController : Controller
{
    private StarWarsQuery _starWarsQuery { get; set; }

    public GraphQLController(StarWarsQuery starWarsQuery)
    {
        _starWarsQuery = starWarsQuery;
    }

    [HttpPost]
    public async Task<IActionResult> Post([FromBody] GraphQLQuery query)
    {
        var schema = new Schema { Query = _starWarsQuery };
// ...

• Add Microsoft.EntityFrameworkCore and Microsoft.EntityFrameworkCore.SqlServer Nuget packages to StarWars.Data project

• Create StarWarsContext

using Microsoft.EntityFrameworkCore;
using StarWars.Core.Models;

namespace StarWars.Data.EntityFramework
{
    public class StarWarsContext : DbContext
    {
        public StarWarsContext(DbContextOptions options)
            : base(options)
        {
            Database.EnsureCreated();
        }

        public DbSet<Droid> Droids { get; set; }
    }
}

• Update 'appsetting.json' with database connection

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    }
  },
  "ConnectionStrings": {
    "StarWarsDatabaseConnection": "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=StarWars;Integrated Security=SSPI;integrated security=true;MultipleActiveResultSets=True;"
  }
}

• Create EF droid repository

using StarWars.Core.Data;
using System.Threading.Tasks;
using StarWars.Core.Models;
using Microsoft.EntityFrameworkCore;

namespace StarWars.Data.EntityFramework.Repositories
{
    public class DroidRepository : IDroidRepository
    {
        private StarWarsContext _db { get; set; }

        public DroidRepository(StarWarsContext db)
        {
            _db = db;
        }

        public Task<Droid> Get(int id)
        {
            return _db.Droids.FirstOrDefaultAsync(droid => droid.Id == id);
        }
    }
}

• Create seed data as an extension to StarWarsContext

using StarWars.Core.Models;
using System.Linq;

namespace StarWars.Data.EntityFramework.Seed
{
    public static class StarWarsSeedData
    {
        public static void EnsureSeedData(this StarWarsContext db)
        {
            if (!db.Droids.Any())
            {
                var droid = new Droid
                {
                    Name = "R2-D2"
                };
                db.Droids.Add(droid);
                db.SaveChanges();
            }
        }
    }
}

• Configure dependency injection a