Call WeatherAPI with HttpClient - asp.net-core

Question

I created Web API to receive daily temperature from OpenWeatherAPI.
I put the API call in the MVC project; (plan to create new project later for better microservice architecture.)
Someone had mentioned in the code:
in your HomeController you're attempting to simply just call the action like a method on an instance of WeatherController. You need to use HttpClient there as well. Also, don't new up HttpClient directly. It should be treated as a singleton
How would I conduct this? This is the original code, started programming month ago.
MVC Page:
namespace WeatherPage.Controllers
{
public class HomeController : Controller
{
public WeatherController weathercontroller = new WeatherController();
public IActionResult Index()
{
return View();
}
public Async Task<IActionResult> About()
{
ViewData["Message"] = "Your application description page.";
ViewData["test"] = weathercontroller.City("Seattle");
return View();
}
}
}
API Controller:
[Route("api/[controller]")]
public class WeatherController : ControllerBase
{
[HttpGet("[action]/{city}")]
public async Task<IActionResult> City(string city)
{
Rootobject rawWeather = new Rootobject();
using (var client = new HttpClient())
{
try
{
client.BaseAddress = new Uri("http://api.openweathermap.org");
var response = await client.GetAsync($"/data/2.5/weather?q={city}&appid=APIkey&units=metric");
response.EnsureSuccessStatusCode();
var stringResult = await response.Content.ReadAsStringAsync();
rawWeather = JsonConvert.DeserializeObject<Rootobject>(stringResult);
return Ok(rawWeather);
}
catch (HttpRequestException httpRequestException)
{
return BadRequest($"Error getting weather from OpenWeather: {httpRequestException.Message}");
}
}
}
}
public class Rootobject
{
public Coord coord { get; set; }
public Weather[] weather { get; set; }
public string _base { get; set; }
public Main main { get; set; }
public int visibility { get; set; }
public Wind wind { get; set; }
public Clouds clouds { get; set; }
public int dt { get; set; }
public Sys sys { get; set; }
public int id { get; set; }
public string name { get; set; }
public int cod { get; set; }
}
This works in my project:
https://localhost:55555/api/weather/city/washington
Retrieve Data From Third party Openweather Api
Should We Call Web Api from Mvc Application in Same Solution

Answer 1

It roughly means you should use dependency injection .
Don't create an instance of HttpClient every time when you need it , just ask for an instance of HttpClient instead .
Extract your code of getting weather in the weather controller into a service , and ask for the service both in weather controller api and home controller
The WeatherService :
public interface IWeatherService
{
Task<Rootobject> CityAsync(string city);
}
public class WeatherService : IWeatherService{
private HttpClient _httpClient ;
public WeatherService(IHttpClientFactory clientFactory){
this._httpClient = clientFactory.CreateClient();
}
public async Task<Rootobject> CityAsync(string city){
Rootobject rawWeather = new Rootobject();
this._httpClient.BaseAddress = new Uri("http://api.openweathermap.org");
var response = await this._httpClient.GetAsync($"/data/2.5/weather?q={city}&appid=APIkey&units=metric");
response.EnsureSuccessStatusCode();
var stringResult = await response.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<Rootobject>(stringResult);
}
}
The new WeatherController :
[Route("api/[controller]")]
public class WeatherController : ControllerBase
{
private IWeatherService _weatherService;
public WeatherController(IWeatherService wetherService ){
this._weatherService= wetherService;
}
[HttpGet("[action]/{city}")]
public async Task<IActionResult> City(string city)
{
try
{
var rawWeather=await this._weatherService.CityAsync(city);
return Ok(rawWeather);
}
catch (HttpRequestException httpRequestException)
{
return BadRequest($"Error getting weather from OpenWeather: {httpRequestException.Message}");
}
}
}
The new HomeController:
public class HomeController : Controller
{
private IWeatherService _weatherService;
public HomeController(IWeatherService wetherService ){
this._weatherService= wetherService;
}
public IActionResult Index()
{
return View();
}
public async Task<IActionResult> About()
{
ViewData["Message"] = "Your application description page.";
ViewData["test"] = await this._weatherService.CityAsync("Seattle");
return View();
}
}
The ConfigureServices:
services.AddHttpClient();
services.AddSingleton<IWeatherService ,WeatherService>();