Implemented Core client

Cloudflare/Auth/ApiTokenAuthentication.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Net.Http;
+using System.Net.Http.Headers;
+
+namespace AMWD.Net.Api.Cloudflare.Auth
+{
+	/// <summary>
+	/// Implements the interface to authenticate using an API token.
+	/// </summary>
+	public class ApiTokenAuthentication : IAuthentication
+	{
+		private readonly string _apiToken;
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="ApiTokenAuthentication"/> class.
+		/// </summary>
+		/// <param name="apiToken">The API token.</param>
+		public ApiTokenAuthentication(string apiToken)
+		{
+			if (string.IsNullOrWhiteSpace(apiToken))
+				throw new ArgumentNullException(nameof(apiToken));
+
+			_apiToken = apiToken;
+		}
+
+		/// <inheritdoc />
+		public void AddHeader(HttpClient httpClient)
+		{
+			httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", _apiToken);
+		}
+	}
+}