GraphQL Introduction and Product Application using .NET Core 7

Step 6

Create IProductService and ProductService inside the repositories folder.

IProductService

using graphql_demo.Entities;

namespace graphql_demo.Repositories
{
    public interface IProductService
    {
        public Task<List<ProductDetails>> ProductListAsync();

        public Task<ProductDetails> GetProductDetailByIdAsync(Guid productId);

        public Task<bool> AddProductAsync(ProductDetails productDetails);

        public Task<bool> UpdateProductAsync(ProductDetails productDetails);

        public Task<bool> DeleteProductAsync(Guid productId);
    }
}

ProductService

using graphql_demo.Data;
using graphql_demo.Entities;
using Microsoft.EntityFrameworkCore;

namespace graphql_demo.Repositories
{
    public class ProductService : IProductService
    {
        private readonly DbContextClass dbContextClass;

        public ProductService(DbContextClass dbContextClass)
        {
            this.dbContextClass = dbContextClass;
        }

        public async Task<List<ProductDetails>> ProductListAsync()
        {
            return await dbContextClass.Products.ToListAsync();
        }

        public async Task<ProductDetails> GetProductDetailByIdAsync(Guid productId)
        {
            return await dbContextClass.Products.Where(ele => ele.Id == productId).FirstOrDefaultAsync();
        }

        public async Task<bool> AddProductAsync(ProductDetails productDetails)
        {
            await dbContextClass.Products.AddAsync(productDetails);
            var result = await dbContextClass.SaveChangesAsync();
            if (result > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        public async Task<bool> UpdateProductAsync(ProductDetails productDetails)
        {
            var isProduct = ProductDetailsExists(productDetails.Id);
            if (isProduct)
            {
                dbContextClass.Products.Update(productDetails);
                var result = await dbContextClass.SaveChangesAsync();
                if (result > 0)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            return false;
        }

        public async Task<bool> DeleteProductAsync(Guid productId)
        {
            var findProductData = dbContextClass.Products.Where(_ => _.Id == productId).FirstOrDefault();
            if (findProductData != null)
            {
                dbContextClass.Products.Remove(findProductData);
                var result = await dbContextClass.SaveChangesAsync();
                if (result > 0)
                {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            return false;
        }

        private bool ProductDetailsExists(Guid productId)
        {
            return dbContextClass.Products.Any(e => e.Id == productId);
        }
    }
}

Step 7

Add a new GraphQL Folder for queries and mutation types.

Step 8

Next, add ProductQueryTypes inside the query types folder that helps us to fetch product data.

using graphql_demo.Entities;
using graphql_demo.Repositories;

namespace graphql_demo.GraphQL.Types
{
    public class ProductQueryTypes
    {
        public async Task<List<ProductDetails>> GetProductListAsync([Service] IProductService productService)
        {
            return await productService.ProductListAsync();
        }

        public async Task<ProductDetails> GetProductDetailsByIdAsync([Service] IProductService productService, Guid productId)
        {
            return await productService.GetProductDetailByIdAsync(productId);
        }
    }
}

Step 9

Create a mutation types folder and add ProductMutations class inside, which helps us add, update and delete product data.

using graphql_demo.Entities;
using graphql_demo.Repositories;

namespace graphql_demo.GraphQL.Mutations
{
    public class ProductMutations
    {
        public async Task<bool> AddProductAsync([Service] IProductService productService,
    ProductDetails productDetails)
        {
            return await productService.AddProductAsync(productDetails);
        }

        public async Task<bool> UpdateProductAsync([Service] IProductService productService,
    ProductDetails productDetails)
        {
            return await productService.UpdateProductAsync(productDetails);
        }

        public async Task<bool> DeleteProductAsync([Service] IProductService productService,
   Guid productId)
        {
            return await productService.DeleteProductAsync(productId);
        }
    }
}

Step 10

Register a few services and middleware inside the Program class related to the repository, seed data, query and mutation type, and many more.

using graphql_demo.Data;
using graphql_demo.GraphQL.Mutations;
using graphql_demo.GraphQL.Types;
using graphql_demo.Repositories;
using Microsoft.EntityFrameworkCore;

var builder = WebApplication.CreateBuilder(args);

//Register Service
builder.Services.AddScoped<IProductService, ProductService>();

//InMemory Database
builder.Services.AddDbContext<DbContextClass>
(o => o.UseInMemoryDatabase("GraphQLDemo"));

//GraphQL Config
builder.Services.AddGraphQLServer()
    .AddQueryType<ProductQueryTypes>()
    .AddMutationType<ProductMutations>();

var app = builder.Build();

//Seed Data
using (var scope = app.Services.CreateScope())
{
    var services = scope.ServiceProvider;
    var context = services.GetRequiredService<DbContextClass>();

    SeedData.Initialize(services);
}

//GraphQL
app.MapGraphQL();

app.UseHttpsRedirection();

app.Run();

Step 11

Run application

• Get a Product List

• Add Product Detail

• Update Product Detail

• Delete Product Detail

• Get Product Detail by Id

GitHub Link

• https://github.com/Jaydeep-007/graphql_demo

Conclusion

Here we discussed the basics of GraphQL, features, and step-by-step implementation using .NET Core Web API.

Happy Coding!!!