Web API Self-Hosting

In this blog, we will learn how to self-host a Web API (call the Web API from a client application) in C#.

Self-hosting means running our ASP.NET Web API project on our own Web Server rather than using IIS. Here, we are not building a complete HTTP Web Server either. We’re simply using the functionality.

 

Introduction

 

This blog shows the walkthrough of how to call a Web API from a client application which we have created earlier.

 

Let's start by creating a simple console application to the existing solution which we have created.

 

Step 1

 

Right-click the Solution Explorer and select "Add New Project".

 

 

 

Step 2

 

Install Microsoft.AspNet.WebApi.SelfHost through Packager Manager console, as shown below.

 

Click on Tools--->Select Library Package Manager-->Package Manager Console and type the following command.

 

 

 

nuget package manager is: Install-Package Microsoft.AspNet.WebApi.SelfHost -Version 5.2.7

 

Step 3

 

Now, add a reference in TestClient to the SampleSelfHost project.

 

In Solution Explorer, right-click the ClientApp project and select "Add Reference". In the "Reference Manager" dialog, under Solution, select Projects. Select the SelfHost project. Click "OK".

 

Step 4

 

Now, open the Program.cs file and add the following implementation. Then, run the project by setting it as a startup project. 

using System;
using System.Collections.Generic;
using System.Net.Http;
namespace TestClient {
    class Program {
        static HttpClient client = new HttpClient();
        static void Main(string[] args) {
            client.BaseAddress = new Uri("http://localhost:8080");
            ListAllStudents();
            ListStudent(1);
            ListStudents("seventh");
            Console.WriteLine("Press Enter to quit.");
            Console.ReadLine();
        }
        static void ListAllStudents() {
            //Call HttpClient.GetAsync to send a GET request to the appropriate URI
            HttpResponseMessage resp = client.GetAsync("api/students").Result;
            //This method throws an exception if the HTTP response status is an error code.
            resp.EnsureSuccessStatusCode();
            var students = resp.Content.ReadAsAsync < IEnumerable < SampleSelfHost.Student >> ().Result;
            foreach(var p in students) {
                Console.WriteLine("{0} {1} {2} ({3})", p.Id, p.Name, p.Standard, p.Marks);
            }
        }
        static void ListStudent(int id) {
            var resp = client.GetAsync(string.Format("api/students/{0}", id)).Result;
            resp.EnsureSuccessStatusCode();
            var student = resp.Content.ReadAsAsync < SampleSelfHost.Student > ().Result;
            Console.WriteLine("ID {0}: {1}", id, student.Name);
        }
        static void ListStudents(string standard) {
            Console.WriteLine("Students in '{0}':", standard);
            string query = string.Format("api/students?standard={0}", standard);
            var resp = client.GetAsync(query).Result;
            resp.EnsureSuccessStatusCode();
            //This method is an extension method, defined in System.Net.Http.HttpContentExtensions
            var students = resp.Content.ReadAsAsync < IEnumerable < SampleSelfHost.Student >> ().Result;
            foreach(var student in students) {
                Console.WriteLine(student.Name);
            }
        }
    }
}

Conclusion

 

In this blog, we have learned how to call a Web API from a console application.