Asp.Net Web Api Returning Httpresponsemessage Vs Iactionresult Complete Guide

Step-by-Step Guide: ASP.NET Web API Returning HttpResponseMessage vs. IActionResult

Prerequisites:

1. Visual Studio installed.
2. Basic understanding of C#, ASP.NET Web API, and HTTP methods.

What We Will Build:

A simple ASP.NET Web API that returns an example response using both HttpResponseMessage and IActionResult.

Step 1: Create a New ASP.NET Web API Project

1. Open Visual Studio.
2. Go to File > New > Project.
3. Select the "ASP.NET Core Web Application" template.
4. Name the project ReturningExamples.
5. Click "Create."
6. Choose the "Web API" template.
7. Click "Create."

Step 2: Understand HttpResponseMessage

HttpResponseMessage is a class used to represent an HTTP response message that includes the status code, headers, and optional content.

Create a Controller Returning HttpResponseMessage

1. Right-click on the Controllers folder in Solution Explorer.
2. Select "Add" > "Controller...".
3. Select "API Controller - Empty".
4. Name the controller HttpResponseMessageController.
5. Add the following code to the controller:

using Microsoft.AspNetCore.Mvc;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;

namespace ReturningExamples.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class HttpResponseMessageController : ControllerBase
    {
        [HttpGet]
        public async Task<HttpResponseMessage> Get()
        {
            var response = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new StringContent("Hello from HttpResponseMessage")
            };
            response.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("text/plain");
            return response;
        }
    }
}

Step 3: Understand IActionResult

IActionResult is an interface representing the action result that can be returned by a Web API controller. It provides more flexibility in the return types and makes the code easy to unit test.

Create a Controller Returning IActionResult

1. Right-click on the Controllers folder in Solution Explorer.
2. Select "Add" > "Controller...".
3. Select "API Controller - Empty".
4. Name the controller IActionResultController.
5. Add the following code to the controller:

using Microsoft.AspNetCore.Mvc;

namespace ReturningExamples.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class IActionResultController : ControllerBase
    {
        [HttpGet]
        public IActionResult Get()
        {
            return Ok("Hello from IActionResult");
        }
    }
}

Step 4: Test the API

1. Run the application by pressing F5 or Ctrl+F5.
2. Open a browser or a tool like Postman.
3. Navigate to http://localhost:<port>/api/httpresponsemessage to test the HttpResponseMessage.
4. Navigate to http://localhost:<port>/api/iactionresult to test the IActionResult.

Step 5: Compare the Outputs

HttpResponseMessage Output:

• Directly returns the response message.
• You need to set the content type manually.
• Provides more control over the HTTP response message.

IActionResult Output:

• Utilizes framework-provided helpers like Ok(), NotFound(), etc.
• Automatically sets the content type based on the return value (e.g., plain text, JSON).
• Easier to read and maintain.
• Better integration with ASP.NET Core's error handling and content negotiation.

Conclusion

Both HttpResponseMessage and IActionResult have their use cases. For most scenarios, IActionResult is preferred due to its simplicity and cleaner code. However, HttpResponseMessage gives you more control when fine-grained manipulation of HTTP responses is required.