How to use HTTP Client in C#

Introduction

HttpClient is a class in C# that is used for making HTTP calls of different kinds (most commonly Get/Put/Delete/Post)

This class comes from System.Net.Http namespace

Methods of Class

Most commonly used methods of this class are

• GetAsync
• DeleteAsync
• PostAsync
• PutAsync

Each CRUD method has 4 overloads which serve same purpose with a little bit addition e.g. (Cancellation Token Support )

Dummy API’s and Get Call

Enough talking let’s see the code , there are bunch of free APIs available that contains data over the internet e.g. RestCountriesAPI and PokeAPI , you can use them for retrieving data , for this Newsletter I have used one of my local project and RestCountriesAPI.

HttpClient httpClient = new HttpClient();
string apiURL = "https://restcountries.com/v3.1/region/europe";

var response = await httpClient.GetAsync(apiURL);

if (response.IsSuccessStatusCode)
{
    var data = await response.Content.ReadAsStringAsync();
    // Deserialize the data into your desired model and use it
}
else
{
    Console.Write(response.StatusCode.ToString());
}

After finishing your work you can call Dispose()to free resources

Properties

HttpClient class has some properties that we can set before making HTTP Call.

• Base Address - To set base address one time
• DeafultRequestHeaders - To add media types that are supported

using System.Net.Http.Headers;

HttpClient client = new HttpClient();
string baseAddress = "https://localhost:7265/";
string apiURL = "/api/Dropdown/Categories";

client.BaseAddress = new Uri(baseAddress);
client.DefaultRequestHeaders.Accept.Add(
    new MediaTypeWithQualityHeaderValue("application/json"));

var response = await client.GetAsync(apiURL);

if (response.IsSuccessStatusCode)
{
    var data = await response.Content.ReadAsStringAsync();
    // Deserialize the data into your desired model and use it
}
else
{
    Console.Write(response.StatusCode.ToString());
}

On similar pattern you can make Put/Delete and Post Calls

How to use this with Dependency Injection

1. Add the service by services.AddHttpClient(),you can set the base address and Default Request headers in service as well .

2. After adding service , just inject IHttpClient in your desired class and use it.