Skip to main content

.Net Core Sample Example On HttpClientFactory Basic Implementation With HttpRequestMessage Object.



In this article, we are going to see the HTTP client factory's basic implementation technique to consume an API in our .Net Core application. Click here to understand how HttpClientFactory works.

Create A Sample API Project:

Now let's create a .net core web API sample project in which we are going to consume another API(Third-party API) using HttpClientFactory. You can create your sample project using editors like Visual Studio 2019 or Visual Studio Code.

Test API To Consume:

Let's consume a free Rest API to consume for our leaning process. There a lot of free developer API for learning purposes. Here we are going to use JSONPlaceholder.
JSONPlaceholder:

Guide :- https://jsonplaceholder.typicode.com/guide.html

Endpoints:-
1.https://jsonplaceholder.typicode.com/users/1/todos (Todos endpoint)
2.https://jsonplaceholder.typicode.com/users/1/albums (Albums endpoint)
3.https://jsonplaceholder.typicode.com/albums/1/photos (Photos endpoint)
4.https://jsonplaceholder.typicode.com/users/1/posts (Posts endpoint)
5.https://jsonplaceholder.typicode.com/posts/1/comments (Comments endpoint)
Here in our sample, we are going to consume Todos's endpoint from the JSONPlaceholder test API.

Register HttpClient:

To use HttpClientFactoy as an injectable service we need to configure the HttpClient extension method in the startup.cs file.
Startup.cs:
public void ConfigureServices(IServiceCollection services)
{
	// code hidden for display purpose
	services.AddHttpClient();
}

Inject HttpClientFactory:

Let's create a web API controller that has HttpClientFactory injected.
Controllers/TodosController.cs:
using System.Net.Http;
using Microsoft.AspNetCore.Mvc;

namespace TestApi.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class TodosController : ControllerBase
    {
        private readonly IHttpClientFactory _httpClientFactory;
        public TodosController(IHttpClientFactory httpClientFactory)
        {
            _httpClientFactory = httpClientFactory;
        }
    }
}

Todos Model Object:

Now let's create a model object Todos that represents the payload object of third-party API which we will consume in upcoming steps.
Models/Todos.cs:
namespace TestApi.Models
{
    public class Todos
    {
        public int UserId { get; set; }
        public int Id { get; set; }
        public string Title { get; set; }
        public bool Completed { get; set; }
    }
}

HttpRequestMessage Object:

System.Net.Http.HttpRequestMessage object that comes with overloaded constructors where we can pass our configuration to make an external request. This HttpRequeMessage object will be used by HttpClient to make an external API call. HttpRequestMessage can be configured with an API endpoint,
Http verb type, headers, token information, etc. In simple words, we will prepare HttpRequesMessage with all configuration inputs to make an API call.

Get Action Method:

Let's create get action method endpoint that is going to consume a third-party Todos API list.
Controllers/TodosController:
using System.Collections.Generic;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using TestApi.Models;

namespace TestApi.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class TodosController : ControllerBase
    {
        [HttpGet]
        [Route("get-all")]
        public async Task<IActionResult> GetAllAsync()
        {
            var request = new HttpRequestMessage(HttpMethod.Get, "https://jsonplaceholder.typicode.com/users/1/todos");

            var httpClient = _httpClientFactory.CreateClient();

            var response = await httpClient.SendAsync(request);

            if (!response.IsSuccessStatusCode)
            {
                return NotFound();
            }

            var responseString = await response.Content.ReadAsStringAsync();
            var options = new JsonSerializerOptions
            {
                PropertyNameCaseInsensitive = true
            };
            List<Todos> todos = JsonSerializer.Deserialize<List<Todos>>(responseString, options);
            return Ok(todos);
        }
    }
}
  • #L18 at this line instantiated HttpRequestMessage object. HttpRequestMessage instance comes with multiple constructors, here we are passing the HttpVerb type of action and the third-party endpoint of Todos.
  • #L20 at this line creating HttpClient object using the HttpClientFactory.
  • #L22 at this line we are making an API call by sending the HttpRequestMessage object as an input parameter to the HttpClient SendAsync method.
  • #L24 at this line we are checking our API call success or not.
  • #L29 at this line we are reading API response as string content.
  • #L30-L33 JsonSerilizerOptions object initialized with a configuration of ignoring case sensitive of payload.
  • #L34 JsonSerializer object used to deserialize our string response to type Todo object collection.
Run the application and access the endpoint and output shows as below.

Post Action Method:

Post endpoint generally used for both creating and updating the records. The 'HttpRequestMessage.Content' property accepts the stringified payload. Using 'System.Net.Http.StringContent' instance is used to generate the stringified payload.
Controller/TodosController.cs:
using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using TestApi.Models;

namespace TestApi.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class TodosController : ControllerBase
    {
		// code hidden for display purpose

        [HttpPost]
        [Route("create")]
        public async Task<IActionResult> Post(Todos newTodos)
        {
            var newTodosJson = JsonSerializer.Serialize<Todos>(newTodos);

            var request = new HttpRequestMessage(HttpMethod.Post, "https://jsonplaceholder.typicode.com/users/1/todos");

            request.Content = new StringContent(newTodosJson, Encoding.UTF8, "application/json");

            var httpClient = _httpClientFactory.CreateClient();

            var response = await httpClient.SendAsync(request);

            if (!response.IsSuccessStatusCode)
            {
               return Ok(new{ Message = "Failed"});
            }

            return Ok(new {Message = "Success"});
        }

    }
}
  • #L21 'System.Text.Json.JsonSerializer.Serialize<T>' is used to convert a Type object to a string. So here we converting our Todos post object to a string.
  • #L23 'System.Net.Http.HttpMethod.Post' method determines the API call as 'Post' call. Here we are passing call type and URL as input parameters to the HttpRequestMessage constructor.
  • #L24 To send payload for the post API call, HttpRequestMessage.Content property of type 'System.Net.Http.HttpConent' which accepts the payload. Now to send our string payload we are going to use the 'System.Net.Http.StringContent' object which inherits the 'System.Net..Http.HttpContent'. 
Let's test the post endpoint as below.

Delete Action Method:

The delete action method is to delete the records. For record deletion no need to post the entire record payload to the server, so sending id(mostly primary key unique identifier to the record) is enough for the deletion endpoint in general.
Note:
Todo endpoint returning 404 not found. So to understand deletion endpoint succesfully here in the sample below we are going to use Post endpoint.
Controllers/TodosController.cs:
using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using TestApi.Models;

namespace TestApi.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class TodosController : ControllerBase
    {
        [HttpDelete]
        [Route("delete")]
        public async Task<IActionResult> Delete(int id)
        {
            var request = new HttpRequestMessage(HttpMethod.Delete, $"https://jsonplaceholder.typicode.com/posts/{id}");

            var httpClient = _httpClientFactory.CreateClient();

            var response = await httpClient.SendAsync(request);

            if (!response.IsSuccessStatusCode)
            {
                return Ok(new {Message = "Failed To Delete Todo"});
            }
            return Ok(new {Message ="Successfully Deleted Todo"});
        }

    }
}
Now run the application and the output shows as below.

Support Me!
Buy Me A Coffee PayPal Me

Wrapping Up:

Hopefully, I think this article delivered some useful information about the HttpClientFactory basic implementation using the HttpRequestMessage object. I love to have your feedback, suggestions, and better techniques in the comment section below.

Follow Me:

Comments

Popular posts from this blog

Blazor WebAssembly Custom Authentication From Scratch

In this article, we are going to explore and implement custom authentication from the scratch. In this sample, we will use JWT authentication for user authentication. Main Building Blocks Of Blazor WebAssembly Authentication: The core concepts of blazor webassembly authentication are: AuthenticationStateProvider Service AuthorizeView Component Task<AuthenticationState> Cascading Property CascadingAuthenticationState Component AuthorizeRouteView Component AuthenticationStateProvider Service - this provider holds the authentication information about the login user. The 'GetAuthenticationStateAsync()' method in the Authentication state provider returns user AuthenticationState. The 'NotifyAuthenticationStateChaged()' to notify the latest user information within the components which using this AuthenticationStateProvider. AuthorizeView Component - displays different content depending on the user authorization state. This component uses the AuthenticationStateProvider

How Response Caching Works In Asp.Net Core

What Is Response Caching?: Response Caching means storing of response output and using stored response until it's under it's the expiration time. Response Caching approach cuts down some requests to the server and also reduces some workload on the server. Response Caching Headers: Response Caching carried out by the few Http based headers information between client and server. Main Response Caching Headers are like below Cache-Control Pragma Vary Cache-Control Header: Cache-Control header is the main header type for the response caching. Cache-Control will be decorated with the following directives. public - this directive indicates any cache may store the response. private - this directive allows to store response with respect to a single user and can't be stored with shared cache stores. max-age - this directive represents a time to hold a response in the cache. no-cache - this directive represents no storing of response and always fetch the fr

Endpoint Routing In Asp.Net Core

How Routing Works In  Core 2.1 And Below Versions?: In Asp.Net Core routing is configured using app.UseRouter() or app.UseMvc() middleware. app.UseMvc(routes => { routes.MapRoute( name: "default", template: "{controller=Home}/{action=Index}/{id?}"); }); Here in Dotnet Core version 2.1 or below versions on the execution of route middleware request will be navigated appropriate controller matched to the route. An operation or functionality which is dependent on route URL or route values and that need to be implemented before the execution of route middleware can be done by accessing the route path from the current request context as below app.Use(async (context, next) => { if(context.Request.Path.Value.IndexOf("oldvehicle") != -1) { context.Response.Redirect("vehicle"); } else { await next(); } }); app.UseMvc(routes => { routes.MapRoute( name: "vehicleRoute", template: "vehicle", defaul

Asp.Net Core MVC Form Validation Techniques

Introduction: Form validations in any applications are like assures that a valid data is storing on servers. All programing frameworks have their own individual implementations for form validations. In Dotnet Core MVC application server-side validations carried on by the models with the help of Data Annotations and the client-side validations carried by the plugin jQuery Unobtrusive Validation. jQuery Unobtrusive Validation is a custom library developed by Microsoft based on the popular library  jQuery Validate . In this article, we are going to learn how the model validation and client-side validation works in Asp.Net Core MVC Application with sample examples. Getting Started: Let's create an Asp.Net Core MVC application project using preferred editors like Microsoft Visual Studio or Microsoft Visual Studio Code. Here I'm using Visual Studio. Let's create an MVC controller and name it as 'PersonController.cs' and add an action method as bel

.Net5 Web API Managing Files Using Azure Blob Storage

In this article, we are going to understand the different file operations like uploading, reading, downloading, and deleting in .Net5 Web API application using Azure Blob Storage. Azure Blob Storage: Azure blob storage is Microsoft cloud storage. Blob storage can store a massive amount of file data as unstructured data. The unstructured data means not belong to any specific type, which means text or binary data. So something like images or pdf or videos to store in the cloud, then the most recommended is to use the blob store. The key component to creating azure blob storage resource: Storage Account:- A Storage account gives a unique namespace in Azure for all the data we will save. Every object that we store in Azure Storage has an address. The address is nothing but the unique name of our Storage Account name. The combination of the account name and the Azure Storage blob endpoint forms the base address for each object in our Storage account. For example, if our Storage Account is n

.Net5 Web API Redis Cache Using StackExchange.Redis.Extensions.AspNetCore Library

In this article, we are going to explore the integration of Redis cache in .Net5 Web API application using the 'StackExchange.Redis.Exntensions' library. Note:- Microsoft has introduced an 'IDistributedCache' interface in dotnet core which supports different cache stores like In-Memory, Redis, NCache, etc. It is simple and easy to work with  'IDistributedCache', for the Redis store with limited features but if we want more features of the Redis store we can choose to use 'StackExchange.Redis.Extensions'.  Click here for Redis Cache Integration Using IDistributedCache Interface . Overview On StackExchange.Redis.Extnesions Library: The 'StackExchange.Redis.Extension' library extended from the main library 'StackExchange.Redis'. Some of the key features of this library like: Default serialization and deserialization. Easy to save and fetch complex objects. Search key. Multiple Database Access Setup Redis Docker Instance: For this sampl

.NET Core MVC Application File Upload To Physical Location With Buffered Technique

Buffering Technique In File Upload: The server will use its Memory(RAM) or Disk Storage to save the files on receiving a file upload request from the client.  Usage of Memory(RAM) or Disk depends on the number of file requests and the size of the file.  Any single buffered file exceeding 64KB is moved from Memory to a temp file on disk.  If an application receives heavy traffic of uploading files there might be a chance of out of Disk or RAM memory which leads to crash application. So this Buffer technique used for small files uploading. In the following article, we create a sample for the file uploading using .NET Core MVC application. Create The .NET Core MVC Project: Let's create a .NET Core MVC project, here for this sample I'm using Visual Studio Code as below.   Check the link to use the Visual Studio Code for .NET Core Application . IFormFile: Microsoft.AspNetCore.Http.IFormFile used for file upload with buffered technique. On uploading files f

Ionic Picker Sample Code In Angular

Introduction: Ionic Picker(ion-picker) is a popup slides up from the bottom of the device screen, which contains rows with selectable column separated items. The main building block of ion-picker as follows: PickerController PickerOptions PickerController: PickerController object helps in creating an ion-picker overlay. create(opts?: Opts): Promise<Overlay> PickerController create method helps in create the picker overlay with the picker options PickerOptions: PickerOptions is a configuration object used by PickerController to display ion-picker. Single Column Ionic Picker: single.item.picker.ts: import { Component } from "@angular/core"; import { PickerController } from "@ionic/angular"; import { PickerOptions } from "@ionic/core"; @Component({ selector: "single-column-picker", templateUrl:"single.item.picker.html" }) export class SingleItemPicker { animals: string[] = ["Tiger&quo

NestJS File Upload

In this article, we are going to understand the steps to create a file uploading endpoint in the NestJS application. Key Features In NestJS File Upload: Let us know some key features of NestJS file upload before implementing a sample application. FileInterceptor: The 'FileInterceptor' will be decorated on top of the file upload endpoint. This interceptor will read single file data from the form posted to the endpoint. export declare function FilesInterceptor(fieldName: string, localOptions?: MulterOptions): Type<NestInterceptor>; Here we can observe the 'fieldName' first input parameter this value should be a match with our 'name' attribute value on the form file input field. So our interceptor read our files that are attached to the file input field. Another input parameter of 'MulterOptions' that provides configuration like file destination path, customizing file name, etc. FilesInterceptor: The 'FilesInterceptor' will be decorated on t

.Net Core HttpClient JSON Extension Methods Using System.Net.Http.Json Package

.Net Core 3.0 onwards Microsoft brought up a new package called System.Net.Http.Json. This new package provides JSON extension methods for HttpClient. These JSON extension methods will have a prebuild mechanism for serializing or deserializing response data or payload of HttpClient call. System.Net.Http.Json extension methods that are provided to HttpClient, few of them are mentioned below. GetFromJsonAsync PostAsJsonAsync PutAsJsonAsync ReadFromJsonAsync In this article, we understand System.Net.Http.Json package by implementing the HttpClient samples by with and without JSON extension methods and compare them. Create A .Net Core Web API Sample Application: Let's create a .Net Core sample Web API application, from this application we will consume another Web API by implementing HttpClient calls. We can create a Web API sample application using IDE like Visual Studio 2019(Supports .Net Core 3.0 plus) or  Visual Studio Code . Create A Typed Client: In .Net Core using the Http