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Berkan
Berkan

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Building a CRUD API with ABP Framework, ASP.NET Core, and PostgreSQL

#dotnet #postgres #abp #aspnet

I recently read "Building a CRUD API with ASP.NET Core Web API and PostgreSQL" by M. Oly Mahmud on DEV Community. While it's a solid introduction to building a basic CRUD API, it lacks features like permissions and validation—important for real-world scenarios. Inspired by this, I decided to write a guide that demonstrates how to build a production-ready CRUD API using the ABP Framework, ASP.NET Core, and PostgreSQL. This tutorial adds security, data validation, and leverages ABP's conventions to create a robust API for managing products.

What is ABP Framework?

ABP Framework is an open-source web application framework for building modular, maintainable, and scalable applications using .NET and ASP.NET Core. It provides built-in functionalities for common application requirements like authentication, authorization, logging, monitoring, tenant management, feature management, payment gateway integration(supports Stripe, PayPal, and so on), file management, and even a GDPR module to manage personal data.

Prerequisites

Let's get started!

Step 1: Install ABP CLI

Install the ABP CLI globally:

dotnet tool install -g Volo.Abp.Studio.Cli
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Verify:

abp --version
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Alternatively, you can use ABP Studio to create projects.

Step 2: Create a New ABP Project

Generate an ABP solution with PostgreSQL:

abp new ProductApi -t app -u mvc -dbms PostgreSQL -cs="Host=localhost;Port=5432;Database=ProductApi;Username=root;Password=myPassword" -csf
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Explanation

  • ProductApi: Solution name.
  • -t app: specifies application(layered) template.
  • -u mvc: Includes MVC UI (API layer is included).
  • -dbms PostgreSQL: Uses PostgreSQL as a database management system
  • -cs: PostgreSQL connection string (adjust credentials as needed).
  • -csf: Creates solution folder.

Navigate to the solution:

cd ProductApi
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ABP attempts to create the ProductApi database during project generation if PostgreSQL is running and the connection string is valid. Check the database to confirm.

Step 3: Define Validation Constants

In ProductApi.Domain.Shared, create a Products folder and add ProductConsts.cs:

namespace ProductApi.Products;

public static class ProductConsts
{
    public const int NameMaxLength = 128;
    public const int DescriptionMaxLength = 256;
}
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These constants will be reused for validation in DTOs and database configuration.

Step 4: Define the Product Entity

In the ProductApi.Domain project, create a Products folder and, add Product.cs:

using System;
using Volo.Abp.Domain.Entities.Auditing;

namespace ProductApi.Domain.Products;

public class Product : AuditedAggregateRoot<Guid>
{
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }
}
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  • AuditedAggregateRoot: Provides auditing (e.g., creation time) properties and uses Guid as the type of primary key.

Step 5: Configure the DbContext

In ProductApi.EntityFrameworkCore/EntityFrameworkCore/ProductApiDbContext.cs, add the Products DbSet:

using Microsoft.EntityFrameworkCore;
using ProductApi.Domain.Products;
using ProductApi.Products;
using Volo.Abp.AuditLogging.EntityFrameworkCore;
using Volo.Abp.BackgroundJobs.EntityFrameworkCore;
using Volo.Abp.BlobStoring.Database.EntityFrameworkCore;
using Volo.Abp.Data;
using Volo.Abp.EntityFrameworkCore;
using Volo.Abp.EntityFrameworkCore.Modeling;
using Volo.Abp.FeatureManagement.EntityFrameworkCore;
using Volo.Abp.Identity.EntityFrameworkCore;
using Volo.Abp.PermissionManagement.EntityFrameworkCore;
using Volo.Abp.SettingManagement.EntityFrameworkCore;
using Volo.Abp.OpenIddict.EntityFrameworkCore;
using Volo.Abp.TenantManagement.EntityFrameworkCore;

namespace ProductApi.EntityFrameworkCore;

[ConnectionStringName("Default")]
public class ProductApiDbContext : AbpDbContext<ProductApiDbContext>
{
    public DbSet<Product> Products { get; set; }

    public ProductApiDbContext(DbContextOptions<ProductApiDbContext> options)
        : base(options)
    {

    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        builder.ConfigurePermissionManagement();
        builder.ConfigureSettingManagement();
        builder.ConfigureBackgroundJobs();
        builder.ConfigureAuditLogging();
        builder.ConfigureFeatureManagement();
        builder.ConfigureIdentity();
        builder.ConfigureOpenIddict();
        builder.ConfigureTenantManagement();
        builder.ConfigureBlobStoring();


        builder.Entity<Product>(b =>
        {
            b.ToTable(ProductApiConsts.DbTablePrefix + "Products", ProductApiConsts.DbSchema);
            b.ConfigureByConvention(); //auto configure for the base class props

            b.Property(x => x.Name).IsRequired().HasMaxLength(ProductConsts.NameMaxLength);
            b.Property(x => x.Description).HasMaxLength(ProductConsts.DescriptionMaxLength);
            b.Property(x => x.Price).IsRequired();
        });
    }
}
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The constraints (e.g., NameMaxLength) align with ProductConsts for consistency across layers.

Add and Apply Migrations

  1. Add a Migration: Navigate to the ProductApi.EntityFrameworkCore project: 
cd ProductApi.EntityFrameworkCore
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Run the EF Core command to create a migration for the Product entity:

dotnet ef migrations add Added_Products
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  • This generates a migration file (e.g., 2025XXXXXXXXXX_Added_Products.cs) in the Migrations folder.
  1. Apply the Migration: Update the database: 
dotnet ef database update
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Ensure PostgreSQL is running and the connection string is correct. This creates the AppProducts table in ProductApi.

Alternatively, ABP applies migrations automatically when you run the ProductApi.DbMigrator project.

Step 6: Define DTOs with Validation

In the ProductApi.Application.Contracts project, create a Products folder and add ProductDtos.cs:

using System;
using System.ComponentModel.DataAnnotations;
using Volo.Abp.Application.Dtos;

namespace ProductApi.Products;

public class ProductDto : AuditedEntityDto<Guid>
{
    public string Name { get; set; }
    public string Description { get; set; }
    public decimal Price { get; set; }
}

public class CreateProductDto
{
    [Required]
    [StringLength(ProductConsts.NameMaxLength)]
    public string Name { get; set; }

    [StringLength(ProductConsts.DescriptionMaxLength)]
    public string Description { get; set; }

    [Required]
    public decimal Price { get; set; }
}

public class UpdateProductDto : EntityDto<Guid>
{
    [Required]
    [StringLength(ProductConsts.NameMaxLength)]
    public string Name { get; set; }

    [StringLength(ProductConsts.DescriptionMaxLength)]
    public string Description { get; set; }

    [Required]
    public decimal Price { get; set; }
}
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  • AuditedEntityDto: Includes auditing properties (e.g., CreationTime).
  • EntityDto: Includes Id property.
  • Validation attributes ensure data integrity (e.g., required fields, length limits).

Step 7: Update Permissions

The ProductApi.Application.Contracts project already contains ProductApiPermissions and ProductApiPermissionDefinitionProvider in Permissions folder. Update ProductApiPermissions.cs:

namespace ProductApi.Permissions;

public static class ProductApiPermissions
{
    public const string GroupName = "ProductApi";

    public static class Products
    {
        public const string Default = GroupName + ".Products";
        public const string Create = Default + ".Create";
        public const string Update = Default + ".Update";
        public const string Delete = Default + ".Delete";
    }
}
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Update ProductApiPermissionDefinitionProvider:

using ProductApi.Localization;
using Volo.Abp.Authorization.Permissions;
using Volo.Abp.Localization;

namespace ProductApi.Permissions;

public class ProductApiPermissionDefinitionProvider : PermissionDefinitionProvider
{
    public override void Define(IPermissionDefinitionContext context)
    {
        var productGroup = context.AddGroup(ProductApiPermissions.GroupName);

        var products = productGroup.AddPermission(ProductApiPermissions.Products.Default, L("Permission:Products"));
        products.AddChild(ProductApiPermissions.Products.Create, L("Permission:Products.Create"));
        products.AddChild(ProductApiPermissions.Products.Update, L("Permission:Products.Update"));
        products.AddChild(ProductApiPermissions.Products.Delete, L("Permission:Products.Delete"));
    }

    private static LocalizableString L(string name)
    {
        return LocalizableString.Create<ProductApiResource>(name);
    }
}
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Update localization in ProductApi.Domain.Shared/Localization/ProductApi/en.json:

{
  "Culture": "en",
  "Texts": {
    "AppName": "ProductApi",
    "Menu:Home": "Home",
    "LongWelcomeMessage": "Welcome to the application. This is a startup project based on the ABP framework. For more information visit",
    "Welcome": "Welcome",
    "Permission:Products": "Manage Products",
    "Permission:Products.Create": "Create Products",
    "Permission:Products.Update": "Update Products",
    "Permission:Products.Delete": "Delete Products"
  }
}
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Step 8: Implement the CRUD Service with CrudAppService

In ProductApi.Application.Contracts/Products, add IProductAppService.cs:

using System;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;

namespace ProductApi.Products;

public interface IProductAppService : ICrudAppService<
    ProductDto,              // DTO for responses
    Guid,                    // Primary key type
    PagedAndSortedResultRequestDto, // Request for GetList
    CreateProductDto,        // Create DTO
    UpdateProductDto>        // Update DTO
{
}
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In ProductApi.Application/Products, add ProductAppService.cs to implement IProductAppService:

using System;
using Microsoft.AspNetCore.Authorization;
using ProductApi.Domain.Products;
using ProductApi.Permissions;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;
using Volo.Abp.Domain.Repositories;

namespace ProductApi.Products;

[Authorize(ProductApiPermissions.Products.Default)]
public class ProductAppService : CrudAppService<
        Product,                  // Entity
        ProductDto,              // DTO for responses
        Guid,                    // Primary key type
        PagedAndSortedResultRequestDto, // Request for GetList
        CreateProductDto,        // Create DTO
        UpdateProductDto>,       // Update DTO
    IProductAppService
{
    public ProductAppService(IRepository<Domain.Products.Product, Guid> repository)
        : base(repository)
    {
        // Define permissions for CRUD operations
        GetPolicyName = ProductApiPermissions.Products.Default;
        GetListPolicyName = ProductApiPermissions.Products.Default;
        CreatePolicyName = ProductApiPermissions.Products.Create;
        UpdatePolicyName = ProductApiPermissions.Products.Update;
        DeletePolicyName = ProductApiPermissions.Products.Delete;
    }
}
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  • [Authorize]: Enforces permission checks.
  • Permissions are assigned to each CRUD operation.

Step 9: Update AutoMapper

The ProductApi.Application project already has ProductApiApplicationAutoMapperProfile.cs. Update it:

using AutoMapper;
using ProductApi.Domain.Products;
using ProductApi.Products;

namespace ProductApi;

public class ProductApiApplicationAutoMapperProfile : Profile
{
    public ProductApiApplicationAutoMapperProfile()
    {
        CreateMap<Product, ProductDto>();
        CreateMap<CreateProductDto, Product>();
        CreateMap<UpdateProductDto, Product>();
    }
}
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Step 10: Run and Test

  1. Build the solution: 
dotnet build
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  1. Run the web project: 
cd ProductApi.Web
dotnet run
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  1. Log In: Open your browser and navigate to https://localhost:xxxx (port varies). Use the default admin credentials:
  • Username: admin
  • Password: 1q2w3E* After logging in, you'll be redirected to the home page.
  1. Access Swagger: Go to https://localhost:xxxx/swagger. ABP includes Swagger UI by default, and since you're logged in, your session token is automatically included in API requests.
  2. Test Endpoints: ABP generates these endpoints from ICrudAppService:
  • GET /api/app/product (list)
  • GET /api/app/product/{id} (get)
  • POST /api/app/product (create)
  • PUT /api/app/product/{id} (update)
  • DELETE /api/app/product/{id} (delete)

In Swagger:

  • Click an endpoint (e.g., POST /api/app/product).
  • Enter a sample request body (e.g., {"name": "Laptop", "description": "High-end", "price": 999.99}).
  • Click "Execute" to test. The response will reflect your authenticated permissions.

If you encounter a 403 (Forbidden) error, ensure the admin role has the required permissions (ProductApi.Products.*) assigned via the UI (Administration > Identity Management > Roles > Actions > Permissions > ProductApi > Select all > Save).

Conclusion

This guide enhances the referenced article by adding real-world features like permissions and validation using ABP Framework. With ICrudAppService, automatic endpoint generation, and consistent validation via ProductConsts, we've built a secure, scalable CRUD API. ABP's conventions make it ideal for production-ready applications—try extending it with custom logic or UI next!

This article was originally posted on the berkansasmaz.com.

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