Implement command auth.getToken (inflatablefriends#154)

src/IF.Lastfm.Core/Api/Commands/Auth/GetTokenCommand.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using IF.Lastfm.Core.Api.Enums;
+using IF.Lastfm.Core.Api.Helpers;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+namespace IF.Lastfm.Core.Api.Commands.Auth
+{
+    [ApiMethodName("auth.getToken")]
+    internal class GetTokenCommand : UnauthenticatedPostAsyncCommandBase<LastResponse<string>>
+    {
+        public GetTokenCommand(ILastAuth auth) : base(auth)
+        {
+        }
+
+        protected override Uri BuildRequestUrl()
+        {
+            return new Uri(LastFm.ApiRootSsl, UriKind.Absolute);
+        }
+
+        public override void SetParameters()
+        {
+        }
+
+        public override async Task<LastResponse<string>> HandleResponse(HttpResponseMessage response)
+        {
+            var json = await response.Content.ReadAsStringAsync();
+
+            if (LastFm.IsResponseValid(json, out LastResponseStatus status) && response.IsSuccessStatusCode)
+            {
+                var token = JsonConvert.DeserializeObject<JObject>(json).GetValue("token");
+                return LastResponse<string>.CreateSuccessResponse(token.Value<string>());
+            }
+            else
+            {
+                return LastResponse.CreateErrorResponse<LastResponse<string>>(status);
+            }
+        }
+    }
+}

src/IF.Lastfm.Core/Api/ILastAuth.cs

@@ -33,10 +33,19 @@ public interface ILastAuth
         /// Authentication Token from the Web Authentication 3.1 (https://www.last.fm/api/webauth)
         /// </summary>
         /// <param name="authToken">Authentication Token</param>
-        /// <returns>Session token used to authenticate calls to last.fm</returns>
+        /// <returns>Session token used to authenticate calls to Last.fm</returns>
         /// <remarks>API: Auth.getSession</remarks>
         Task<LastResponse> GetSessionTokenAsync(string authToken);
 
+        /// <summary>
+        /// Fetch an unathorized request token for an API account.
+        /// This is step 2 of the authentication process for desktop applications. (https://www.last.fm/api/desktopauth)
+        /// </summary>
+        /// <returns>Authentication Token used to get Last.fm Session.
+        /// Authentication tokens are user and API account specific. They are valid for 60 minutes from the moment they are granted.</returns>
+        /// <remarks>API: Auth.getToken</remarks>
+        Task<LastResponse> GetAuthTokenAsync();
+
         /// <summary>
         /// Adds the api_key, method and session key to the provided params dictionary, then generates an MD5 hash.
         /// Parameters contained in the hash must also be exactly the parameters sent to the API.

src/IF.Lastfm.Core/Api/LastAuth.cs

@@ -76,6 +76,15 @@ public async Task<LastResponse> GetSessionTokenAsync(string authToken)
             }
         }
 
+        public async Task<LastResponse> GetAuthTokenAsync()
+        {
+            var command = new GetTokenCommand(this)
+            {
+                HttpClient = HttpClient
+            };
+            return await command.ExecuteAsync();
+        }
+
         public string GenerateMethodSignature(string method, Dictionary<string, string> parameters = null)
         {
             if (parameters == null)