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.NET5 Web API CRUD Operation Using Entity Framework Core

In this article, we are going to understand about the .Net5 Web API CRUD operations using the entity framework core.

Web API:

Web API is a framework for building HTTP services that can be accessed from any client including browser and mobile devices.

In simple terminology API(Application Programming Interface) means an interface module that contains programming functions that can be requested via HTTP calls to serve the data to respective clients.

Some of the key characteristics of API:
  • Supports HTTP verbs like 'GET', 'POST', 'PUT', 'Delete',etc.
  • Supports default responses like 'XML' and 'JSON'. Also can define custom responses.
  • Supports self-hosting or individual hosting, so that all different kind of apps or clients can consume it.
  • Authentication and Authorization are easy to implement.
  • The ideal platform to build REST full services.

Create A .Net5 Web API Application:

Let's begin our journey by creating a sample .Net5 Web API application.

Visual Studio users can easily create .Net5 Web API templated application. On creating application visual studio UI shows different application template option in that we have to select 'ASP NET Core Web API'.

Here for this demo, I'm going to use Visual Studio Code Editor and .NET CLI. Run the below .NET CLI command to create the API application.
CLI Command To API Application:
dotnet new webapi -n your_project_name
Things to aware of about the API project are like:

Controllers - The controllers are classes that will contain methods(API action methods) to serve the HTTP request.

Actions- The action method contains logic to read the request and serve the response to the clients.

Register API Controller Service- In the 'Startup.cs' file we have to register the 'AddController' service.

Swagger- The Swagger is an API Documentation Tool used to test the endpoints.

Register Swagger Service:

Register Swagger Middleware:

Endpoint Routing Middleware-

Entity Framework Core:

Entity Framework Core is an Object/Relational Mapping(ORM) framework. EF Core makes database communication more fluent and easy. 
EF Core supports:
  • Database First Approach.
  • Code First Approach.
Code First Approach means first we will create c# POCO classes and then create the database tables. Code First Approach has one more sub-category like 'Code First With Existing Database'. So the 'Code First With Existing Database' can work with the already created tables in the database which is an ideal choice for real-time development. Our demo will be implemented using 'Code First With Existing Database'.

Install EF Core Nuget:

Now install ef core and SQL ef core extension Nuget package into our application.
Package Manager(Visual Studio):
Install-Package Microsoft.EntityFrameworkCore -Version 5.0.6
Install-Package Microsoft.EntityFrameworkCore.SqlServer -Version 5.0.6
CLI Commands(Visual Studio Code):
dotnet add package Microsoft.EntityFrameworkCore --version 5.0.6
dotnet add package Microsoft.EntityFrameworkCore.SqlServer --version 5.0.6

Sample SQL Script:

To follow the demo, run the SQL script to generate the table.
CREATE TABLE [dbo].[Gadgets](
	[Id] [int] IDENTITY(1,1) NOT NULL,
	[ProductName] [varchar](max) NULL,
	[Brand] [varchar](max) NULL,
	[Cost] [decimal](18, 0) NOT NULL,
	[ImageName] [varchar](1024) NULL,
	[Type] [varchar](128) NULL,
	[CreatedDate] [datetime] NULL,
	[ModifiedDate] [datetime] NULL,
PRIMARY KEY CLUSTERED 
(
	[Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

Setup Entity Framework Core DbContext:

First, let's create POCO class that represents our table. So let's create a new folder 'Data', inside of it create one more folder like 'Entities'. Inside of the 'Entities' folder creates our POCO class.
Data/Entities/Gadgets.cs:
namespace Dotnet5.API.CRUD.EF.Data.Entities
{
    public class Gadgets
    {
        public int Id { get; set; }
        public string ProductName { get; set; }
        public string Brand { get; set; }
        public decimal Cost { get; set; }
        public string Type { get; set; }
    }
}

In EF Core DbContext is like a database that manages all POCO classes(classes represent tables). Inside the 'Data' folder create a context class.
Data/MyWorldDbContext.cs:
using Dotnet5.API.CRUD.EF.Data.Entities;
using Microsoft.EntityFrameworkCore;

namespace Dotnet5.API.CRUD.EF.Data
{
    public class MyWorldDbContext : DbContext
    {
        public MyWorldDbContext(DbContextOptions<MyWorldDbContext> options) : base(options)
        {
 
        }
        public DbSet<Gadgets> Gadgets { get; set; }
    }
}
Add database connection string into 'appsetting.Development.json'.
appsetings.Development.json:
"ConnectionStrings":{
    "MyWorldDbConnection":"your_connection"
}

Register 'MyWorlDbContext' into the dependency services.
services.AddDbContext<MyWorldDbContext>(options =>
{
	options.UseSqlServer(Configuration.GetConnectionString("MyWorldDbConnection"));
});

Create A Sample Controller:

In Web API Controller is entry point of the request. So controller will have methods called actions, these action executed per request based on the route.
Controllers/GagetsController.cs:
using Dotnet5.API.CRUD.EF.Data;
using Microsoft.AspNetCore.Mvc;

namespace Dotnet5.API.CRUD.EF.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class GadgetsController: ControllerBase
    {
        private readonly MyWorldDbContext _myWorldDbContext;
        public GadgetsController(MyWorldDbContext myWorldDbContext)
        {
            _myWorldDbContext = myWorldDbContext;
        }
    }
}
  • (Line: 6) Decorated with 'ApiController' attribute indicates that a type and all derived types are used to serve HTTP API responses. Controller decorated with this attribute are configured wth features and behavior target at improving the developer experience for building APIs.
  • (Line: 7) Route to define our URL. The default expression '[Controller]' means name of the controller means 'Gadgets'. You can define your custom route name if you wanted.
  • (Line: 8) Our c# class to become a controller it need to inherit 'Microsoft.AspNetCore.Mvc.ControllerBase'.
  • (Line: 10-14) Injected our DbContext into the controller.

Read Operation:

Now let's implement an action method for our read operation. In API action methods are logical functions that will get executed and return response to the clients.
Controllers/GadgetsController.cs:
[HttpGet]
[Route("all")]
public IActionResult GetAllGadtets()
{
	var allGadgets = _myWorldDbContext.Gadgets.ToList();
	return Ok(allGadgets);
}
  • (Line: 1)The 'HttpGet' verb decorated means this action method invoked for the get request.
  • (Line: 2) Action method also configured with the part of route like the controller. So to invoke our action method our URL like 'https://localhost:5001/gadgets/all'.
  • (Line: 5) Fetching all data from the database
  • (Line: 6) In API 'Ok' method return status for success like '200'(status code). So our result will be passed through 'OK' method.
Now run the application by default swagger tool will be opened like below.

step1:

step2:

Create Operation:

Let's create new action method for 'Create Operation'. Creating an item comes under HTTP POST request.
Controllers/GadgetsController.cs:
[HttpPost]
[Route("add")]
public IActionResult CreateGadget(Gadgets gadgets)
{
	_myWorldDbContext.Gadgets.Add(gadgets);
	_myWorldDbContext.SaveChanges();
	return Ok(gadgets.Id);
}
  • (Line: 1) Decorated with 'HttpPost', which represents action method should invoke for HTTP POST request.
  • (Line: 2) Defined action method route.
  • (Line: 3) Data posted from the client will be stored in the 'gadgets' object.
  • (Line: 5&6) Saving the record into the database.
  • (Line: 7) Returning the newly create record id value in response.
step1:

step2:

step3:

Update Operation:

Now let's create a new action method for the 'Update Operation'. The HTTP PUT request is the ideal HTTP protocol for the update operation.
Controllers/GadgetsController.cs:
[HttpPut]
[Route("update")]
public IActionResult UpdateGadget(Gadgets gadgets)
{
	_myWorldDbContext.Update(gadgets);
	_myWorldDbContext.SaveChanges();
	return NoContent();
}
  • (Line: 1) Decorated with 'HttpPut' which defines this action method gets executed for the HTTP PUT request.
  • (Line: 2) Defined route for the action method.
  • (Line: 5&6) Updating the data to the database. One more thing to remember is that to update a record it must contain its unique identifier value like the 'Id' column.
  • (Line: 7) Returning method 'NoContent' whose status code is 204. For an HTTP PUT request either we can return 200(Ok) or 204(NoContent) status codes.
step1:

step2:

Delete Operation:

Now let's create a new action method for the 'Delete Operation'. The HTTP Delete protocol is ideal for the delete request.
Controllers/GadgetsController.cs:
[HttpDelete]
[Route("delete/{id}")]
public IActionResult DeleteGadget(int id)
{
	var gadgetToDelete = _myWorldDbContext.Gadgets.Where(_ => _.Id == id).FirstOrDefault();
	if (gadgetToDelete == null)
	{
		return NotFound();
	}

	_myWorldDbContext.Gadgets.Remove(gadgetToDelete);
	_myWorldDbContext.SaveChanges();
	return NoContent();
}
  • (Line: 1) Decorated with 'HttpDelete' that defines action method only gets invoked for the HTTP DELETE requests.
  • (Line: 2) Defined route for the action method. A dynamic expression like '{id}' whose value will be read by the action method as its input parameter.
  • (Line: 5) Fetching the record from the database by querying it with the 'id' value.
  • (Line: 6-8) If the record not found then we simply return method 'NotFound'(status code 404).
  • (Line: 11-12) Removing the record from the database.
  • (Line: 13) Finally returning 'NoContent'(status code 202).
step1:

step2:
That's all about the .Net Web API CRUD operation using the entity framework core.

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Wrapping Up:

Hopefully, I think this article delivered some useful information on .Net5 Web API CRUD operation with the entity framework. I love to have your feedback, suggestions, and better techniques in the comment section below.

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Comments

  1. Good and detailed article.
    Ihave some notes
    - when you are using different http verb you dont meed to have different routes
    - take advantage of async methods when possible
    - dont forget on exceptions

    ReplyDelete

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