Startup.cs

using System;
using AutoMapper;
using JsonApiDotNetCore.Data;
using JsonApiDotNetCore.Extensions;
using JsonApiDotNetCore.Models;
using JsonApiDotNetCore.Services;
using JsonApiDotNetCoreExample.Data;
using JsonApiDotNetCoreExample.Models.Entities;
using JsonApiDotNetCoreExample.Models.Resources;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using ResourceEntitySeparationExample.Models;

namespace ResourceEntitySeparationExample
{
    public class Startup
    {
        public readonly IConfiguration Config;

        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: false)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();

            Config = builder.Build();
        }

        public virtual IServiceProvider ConfigureServices(IServiceCollection services)
        {
            var loggerFactory = new LoggerFactory();
            loggerFactory.AddConsole(LogLevel.Warning);
            services.AddSingleton<ILoggerFactory>(loggerFactory);

            services.AddDbContext<AppDbContext>(options => options
                .UseNpgsql(GetDbConnectionString()),
                ServiceLifetime.Transient);
            services.AddScoped<IDbContextResolver, DbContextResolver<AppDbContext>>();

            var mvcBuilder = services.AddMvcCore();

            services.AddJsonApi(options => {
                options.Namespace = "api/v1";
                options.DefaultPageSize = 10;
                options.IncludeTotalRecordCount = true;
                options.BuildContextGraph((builder) => {
                    builder.AddResource<CourseResource>("courses");
                    builder.AddResource<DepartmentResource>("departments");
                    builder.AddResource<StudentResource>("students");
                });
            }, mvcBuilder);

            services.AddAutoMapper();
            services.AddScoped<IResourceMapper, AutoMapperAdapter>();

            services.AddScoped<IResourceService<CourseResource, int>, EntityResourceService<CourseResource, CourseEntity, int>>();
            services.AddScoped<IResourceService<DepartmentResource, int>, EntityResourceService<DepartmentResource, DepartmentEntity, int>>();
            services.AddScoped<IResourceService<StudentResource, int>, EntityResourceService<StudentResource, StudentEntity, int>>();

            var provider = services.BuildServiceProvider();
            var appContext = provider.GetRequiredService<AppDbContext>();
            if (appContext == null)
                throw new ArgumentException();

            return provider;
        }

        public virtual void Configure(
            IApplicationBuilder app,
            IHostingEnvironment env,
            ILoggerFactory loggerFactory,
            AppDbContext context)
        {
            context.Database.EnsureCreated();
            loggerFactory.AddConsole(Config.GetSection("Logging"));
            app.UseJsonApi();
        }

        public string GetDbConnectionString() => Config["Data:DefaultConnection"];
    }
}