Reusable HttpClient RSS

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  Tim Cadieux

  Member

  438 Points

  328 Posts

  Reusable HttpClient

  Nov 21, 2020 03:07 PM|Tim Cadieux|LINK

  I'm just trying to figure out the cleanest, most efficient way to do recurring HttpClient requests with multiple endPoints.

  I'm trying to do this wthout something like Nuget so I have more transparency over what's happening.

  The below works, however I want to make it reusable with say List<Cities>, List<Cars>, etc...

  Also, I want to always pass certain Headers, say the current UserId from AspNetIdentity

          public static async Task<List<Category>> GetList()
          {
              var Categories = new List<Category>();
              string ActionPath = string.Format("{0}/v1/Categories", Connect.web);
              using (var response = await Client.GetAsync(ActionPath))
              {
                  string apiResponse = await response.Content.ReadAsStringAsync();
                  Categories  = JsonConvert.DeserializeObject<List<Category>>(apiResponse);
              }
              return Categories ;
          }

  I tried use a Base Class, but then I went around in circles trying to call HttpContext from static class, etc...I've looked for examples but there is so much noise online re: HttpClient or HttpClient Factory, I don't know where to start.

  What I was hoping to do was have just a few lines to indicate the specific endPoint, the returnType, etc...am I just living in a fantasy world?

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  mgebhard

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  52201 Points

  23274 Posts

  Re: Reusable HttpClient

  Nov 21, 2020 03:41 PM|mgebhard|LINK

  Use DI to configure HttpClient.  If you have multiple services then create a factory.  These concepts are covered in official documentation.

  https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpclient?view=net-5.0

  https://docs.microsoft.com/en-us/aspnet/core/fundamentals/http-requests?view=aspnetcore-5.0

  Tim Cadieux

  I tried use a Base Class, but then I went around in circles trying to call HttpContext from static class, etc...I've looked for examples but there is so much noise online re: HttpClient or HttpClient Factory, I don't know where to start.

  I feel a base class makes the DI code overly complex.  Use standard DI service patterns and C# generics.   Your service interface will have GET, POST, PUT, DELETE, etc. and perhaps a few method overloads loads.

  For example

  public interface IApiService
  {
      Task<T> GetAsync<T>(string accessToken, string restApi);
  }

  public async Task<T> GetAsync<T>(string accessToken, string restApi)
  {
      _logger.LogDebug($"Api = {restApi}");
  
      T results = (T)Activator.CreateInstance(typeof(T));
  
      var client = _httpClientFactory.CreateClient(_apiFactoryName);
      if (!string.IsNullOrEmpty(accessToken))
      {
          client.SetBearerToken(accessToken);
      }
             
      using (Stream s = await client.GetStreamAsync($"{restApi}"))
      {
          using (StreamReader sr = new StreamReader(s))
          {
              using (JsonReader reader = new JsonTextReader(sr))
              {
                  JsonSerializer serializer = new JsonSerializer();
                  results = serializer.Deserialize<T>(reader);
              }
          }
      }
      return results;
  }

  Your POST implementation will also have input models.