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Posted on Jul 23

# ASP.NET Core Web API — Full CRUD + Image Upload + Swagger (Full-Stack Backend Guide)

#api #csharp #dotnet #tutorial

Intha guide-la Swashbuckle (Swagger), Image Upload, mariyum Full CRUD (Create, Read, Update, Delete) ellam step-by-step cover pannirukom. Update/Delete panrapo pazhaya image-a server-la irundhu automatic-a delete panra logic-um irukku — real-time projects-ku romba mukkiyam.

📁 Final Project Folder Structure

MyCrudApp/
│
├── Controllers/
│   └── ProductController.cs
│
├── Data/
│   └── AppDbContext.cs
│
├── Models/
│   ├── Product.cs
│   └── ProductDto.cs
│
├── Migrations/              👈 (dotnet ef migrations add ku apram auto-generate aagum)
│
├── wwwroot/
│   └── uploads/              👈 (uploaded images ithula store aagum)
│
├── appsettings.json
├── appsettings.Development.json
├── Program.cs
└── MyCrudApp.csproj

Step 1: Project & Packages Setup

dotnet new webapi -n MyCrudApp
cd MyCrudApp
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.Tools
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Swashbuckle.AspNetCore

Design package illama, dotnet ef migrations add command work aagathu — idhu miss pannama add pannunga.

Step 2: Models (Models/Product.cs)

namespace MyCrudApp.Models
{
    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public string Category { get; set; }
        public decimal Price { get; set; }
        public int StockQuantity { get; set; }
        public string ImageUrl { get; set; }
    }
}

Models/ProductDto.cs (Request Model with File)

using Microsoft.AspNetCore.Http;

namespace MyCrudApp.Models
{
    public class ProductDto
    {
        public string Name { get; set; }
        public string Description { get; set; }
        public string Category { get; set; }
        public decimal Price { get; set; }
        public int StockQuantity { get; set; }
        public IFormFile? ImageFile { get; set; } // '?' na Optional (updates ku)
    }
}

Step 3: Data/AppDbContext.cs (Missing piece — idhu illama app run aagathu)

using Microsoft.EntityFrameworkCore;
using MyCrudApp.Models;

namespace MyCrudApp.Data
{
    public class AppDbContext : DbContext
    {
        public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
        {
        }

        public DbSet<Product> Products { get; set; }
    }
}

Step 4: appsettings.json (Connection String add pannunga)

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Database=MyCrudAppDb;Trusted_Connection=True;TrustServerCertificate=True;"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

Local-la SQL Server illana, Server=localhost ku pathila unga SQL Server instance name podunga (e.g. Server=.\\SQLEXPRESS). SQL auth use panra pakshathula User Id=sa;Password=YourPassword; nu maathi podunga.

Step 5: Program.cs (Swagger & Static Files Setup)

using Microsoft.EntityFrameworkCore;
using MyCrudApp.Data;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddDbContext<AppDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("DefaultConnection")));

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();

// Swagger (Swashbuckle) Setup
builder.Services.AddSwaggerGen();

var app = builder.Build();

// Swagger UI Enable panrom
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseStaticFiles(); // Image url browser-la view panna must
app.UseAuthorization();
app.MapControllers();
app.Run();

Step 6: The Ultimate CRUD Controller (Controllers/ProductController.cs)

using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using MyCrudApp.Data;
using MyCrudApp.Models;

namespace MyCrudApp.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class ProductController : ControllerBase
    {
        private readonly AppDbContext _context;
        private readonly IWebHostEnvironment _env;

        public ProductController(AppDbContext context, IWebHostEnvironment env)
        {
            _context = context;
            _env = env;
        }

        // 1. CREATE (POST)
        [HttpPost]
        public async Task<IActionResult> CreateProduct([FromForm] ProductDto dto)
        {
            string imageUrl = "";
            if (dto.ImageFile != null && dto.ImageFile.Length > 0)
            {
                imageUrl = await SaveImage(dto.ImageFile);
            }

            var product = new Product
            {
                Name = dto.Name,
                Description = dto.Description,
                Category = dto.Category,
                Price = dto.Price,
                StockQuantity = dto.StockQuantity,
                ImageUrl = imageUrl
            };

            _context.Products.Add(product);
            await _context.SaveChangesAsync();
            return Ok(product);
        }

        // 2. READ ALL (GET)
        [HttpGet]
        public async Task<IActionResult> GetProducts()
        {
            return Ok(await _context.Products.ToListAsync());
        }

        // 2.1 READ BY ID (GET)
        [HttpGet("{id}")]
        public async Task<IActionResult> GetProduct(int id)
        {
            var product = await _context.Products.FindAsync(id);
            if (product == null) return NotFound();
            return Ok(product);
        }

        // 3. UPDATE (PUT)
        [HttpPut("{id}")]
        public async Task<IActionResult> UpdateProduct(int id, [FromForm] ProductDto dto)
        {
            var product = await _context.Products.FindAsync(id);
            if (product == null) return NotFound();

            // Puthu image anuppi irundha, pazhaya image-a delete panni puthusa save pannanum
            if (dto.ImageFile != null && dto.ImageFile.Length > 0)
            {
                DeleteImage(product.ImageUrl);
                product.ImageUrl = await SaveImage(dto.ImageFile);
            }

            product.Name = dto.Name;
            product.Description = dto.Description;
            product.Category = dto.Category;
            product.Price = dto.Price;
            product.StockQuantity = dto.StockQuantity;

            await _context.SaveChangesAsync();
            return Ok(product);
        }

        // 4. DELETE (DELETE)
        [HttpDelete("{id}")]
        public async Task<IActionResult> DeleteProduct(int id)
        {
            var product = await _context.Products.FindAsync(id);
            if (product == null) return NotFound();

            // Database-la data delete aaga munnadi, server folder-la irundhu image-a delete panrom
            DeleteImage(product.ImageUrl);

            _context.Products.Remove(product);
            await _context.SaveChangesAsync();
            return Ok(new { message = "Product and Image deleted successfully!" });
        }

        // --- Helper Methods ---
        private async Task<string> SaveImage(IFormFile file)
        {
            var uploadsFolder = Path.Combine(_env.WebRootPath, "uploads");
            if (!Directory.Exists(uploadsFolder)) Directory.CreateDirectory(uploadsFolder);

            var uniqueFileName = Guid.NewGuid().ToString() + "_" + file.FileName;
            var filePath = Path.Combine(uploadsFolder, uniqueFileName);

            using (var stream = new FileStream(filePath, FileMode.Create))
            {
                await file.CopyToAsync(stream);
            }
            return $"{Request.Scheme}://{Request.Host}/uploads/{uniqueFileName}";
        }

        private void DeleteImage(string imageUrl)
        {
            if (string.IsNullOrEmpty(imageUrl)) return;
            var fileName = Path.GetFileName(new Uri(imageUrl).LocalPath);
            var filePath = Path.Combine(_env.WebRootPath, "uploads", fileName);
            if (System.IO.File.Exists(filePath))
            {
                System.IO.File.Delete(filePath);
            }
        }
    }
}

Step 7: Database Create Panra Steps (Migration)

Controller and DbContext ready aana apparam, database-a physically create pannanum:

dotnet ef migrations add InitialCreate
dotnet ef database update

Idhu run panna apparam, Products table unga SQL Server database-la automatic-a create aagidum.

wwwroot/uploads folder-a manually create panni vachikonga (illana git-la empty folder track aagathu — venumna .gitkeep file podunga).

Step 8: Swagger-la Test Panra Steps

App-a run pannitu (dotnet run), browser-la http://localhost:<port>/swagger open pannunga.

CREATE (POST)
POST /api/Product → Try it out → Fields fill pannunga → Image choose pannunga → Execute. Data save aagum.

READ (GET)
GET /api/Product → Try it out → Execute. Save aana ella data-vum JSON format-la varum. Athula irukka id-a note panni vachikonga.

UPDATE (PUT)
PUT /api/Product/{id} → Try it out → Note panna id-a mela enter pannunga. Kela form-la details-a maathi (e.g., Price increase pannunga), vera puthu image select pannitu → Execute. Ippo paathingana pazhaya image unga local folder-la irundhu automatic-a delete aagi puthu image vanthurukum!

DELETE (DELETE)
DELETE /api/Product/{id} → Try it out → id enter panni Execute. Database-la irundhu data-vum poidum, unga wwwroot/uploads folder-la irundhu antha specific image-um delete aagidum.

🧠 Quick Recap (Article-ku Highlights)

✅ Swagger UI auto-generated API docs
✅ IFormFile mூlam multipart/form-data image upload
✅ EF Core Code-First approach with Migrations
✅ Old image cleanup logic on Update & Delete
✅ Clean separation: Models / DTOs / Data / Controllers

Intha structure follow pannina, unga dev.to article production-ready backend guide-a maarum. All the best! 🚀

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