Added first OAuth request: client credentials

.vscode/csharp.code-snippets

@@ -1,7 +1,7 @@
 {
-  "model-class": {
+  "class-model": {
     "scope": "csharp",
-    "prefix": "model-class",
+    "prefix": "class-model",
     "body": [
       "namespace SpotifyAPI.Web",
       "{",
@@ -15,9 +15,9 @@
     ],
     "description": "Creates a new model"
   },
-  "request-class": {
+  "class-request": {
     "scope": "csharp",
-    "prefix": "request-class",
+    "prefix": "class-request",
     "body": [
       "namespace SpotifyAPI.Web",
       "{",

SpotifyAPI.Web.Tests/Clients/SpotifyClientConfigTest.cs

@@ -37,9 +37,9 @@ namespace SpotifyAPI.Web
       Assert.AreEqual(null, defaultConfig.HTTPLogger);
       Assert.AreEqual(null, defaultConfig.RetryHandler);
 
-      Assert.IsInstanceOf(typeof(TokenHeaderAuthenticator), defaultConfig.Authenticator);
+      Assert.IsInstanceOf(typeof(TokenAuthenticator), defaultConfig.Authenticator);
 
-      var tokenHeaderAuth = defaultConfig.Authenticator as TokenHeaderAuthenticator;
+      var tokenHeaderAuth = defaultConfig.Authenticator as TokenAuthenticator;
       Assert.AreEqual(token, tokenHeaderAuth.Token);
       Assert.AreEqual(tokenType, tokenHeaderAuth.TokenType);
     }
@@ -51,7 +51,7 @@ namespace SpotifyAPI.Web
       var defaultConfig = SpotifyClientConfig.CreateDefault();
       var tokenConfig = defaultConfig.WithToken(token);
 
-      Assert.AreEqual(token, (tokenConfig.Authenticator as TokenHeaderAuthenticator).Token);
+      Assert.AreEqual(token, (tokenConfig.Authenticator as TokenAuthenticator).Token);
       Assert.AreNotEqual(defaultConfig, tokenConfig);
       Assert.AreEqual(null, defaultConfig.Authenticator);
     }

SpotifyAPI.Web.Tests/Http/APIConnectorTest.cs

@@ -46,7 +46,7 @@ namespace SpotifyAPI.Web.Tests
       );
       await apiConnector.SendAPIRequest<string>(new Uri("/me", UriKind.Relative), HttpMethod.Get).ConfigureAwait(false);
 
-      authenticator.Verify(a => a.Apply(It.IsAny<IRequest>()), Times.Once);
+      authenticator.Verify(a => a.Apply(It.IsAny<IRequest>(), It.IsAny<IAPIConnector>()), Times.Once);
       httpClient.Verify(h => h.DoRequest(It.IsAny<IRequest>()), Times.Once);
       serializer.Verify(s => s.DeserializeResponse<string>(response.Object), Times.Once);
     }
@@ -89,7 +89,7 @@ namespace SpotifyAPI.Web.Tests
       await apiConnector.SendAPIRequest<string>(new Uri("/me", UriKind.Relative), HttpMethod.Get).ConfigureAwait(false);
 
       serializer.Verify(s => s.SerializeRequest(It.IsAny<IRequest>()), Times.Once);
-      authenticator.Verify(a => a.Apply(It.IsAny<IRequest>()), Times.Exactly(2));
+      authenticator.Verify(a => a.Apply(It.IsAny<IRequest>(), It.IsAny<IAPIConnector>()), Times.Exactly(2));
       httpClient.Verify(h => h.DoRequest(It.IsAny<IRequest>()), Times.Exactly(2));
       serializer.Verify(s => s.DeserializeResponse<string>(response.Object), Times.Once);
     }

SpotifyAPI.Web.Tests/Http/TokenAuthenticatorTest.cs

@@ -6,16 +6,18 @@ using SpotifyAPI.Web.Http;
 namespace SpotifyAPI.Web.Tests
 {
   [TestFixture]
-  public class TokenHeaderAuthenticatorTest
+  public class TokenAuthenticatorTest
   {
     [Test]
     public void Apply_AddsCorrectHeader()
     {
-      var authenticator = new TokenHeaderAuthenticator("MyToken", "Bearer");
+      var authenticator = new TokenAuthenticator("MyToken", "Bearer");
       var request = new Mock<IRequest>();
+      var apiConnector = new Mock<IAPIConnector>();
+
       request.SetupGet(r => r.Headers).Returns(new Dictionary<string, string>());
 
-      authenticator.Apply(request.Object);
+      authenticator.Apply(request.Object, apiConnector.Object);
       Assert.AreEqual(request.Object.Headers["Authorization"], "Bearer MyToken");
     }
   }

SpotifyAPI.Web/Clients/APIClient.cs

@@ -11,6 +11,6 @@ namespace SpotifyAPI.Web
       API = apiConnector;
     }
 
-    public IAPIConnector API { get; set; }
+    protected IAPIConnector API { get; set; }
   }
 }

SpotifyAPI.Web/Clients/Interfaces/IOAuthClient.cs

@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace SpotifyAPI.Web
+{
+  public interface IOAuthClient
+  {
+    Task<TokenResponse> RequestToken(ClientCredentialsRequest request);
+  }
+}

SpotifyAPI.Web/Clients/OAuthClient.cs

@@ -0,0 +1,49 @@
+using System.Text;
+using System;
+using System.Net.Http;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using SpotifyAPI.Web.Http;
+
+namespace SpotifyAPI.Web
+{
+  public class OAuthClient : APIClient, IOAuthClient
+  {
+    public OAuthClient(IAPIConnector apiConnector) : base(apiConnector) { }
+    public OAuthClient() : this(SpotifyClientConfig.CreateDefault()) { }
+
+    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1062")]
+    public OAuthClient(SpotifyClientConfig config) : base(ValidateConfig(config)) { }
+
+    public Task<TokenResponse> RequestToken(ClientCredentialsRequest request)
+    {
+      Ensure.ArgumentNotNull(request, nameof(request));
+
+      var form = new List<KeyValuePair<string, string>>
+      {
+        new KeyValuePair<string, string>("grant_type", "client_credentials")
+      };
+
+      var base64 = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{request.ClientId}:{request.ClientSecret}"));
+      var headers = new Dictionary<string, string>
+      {
+        { "Authorization", $"Basic {base64}"}
+      };
+
+      return API.Post<TokenResponse>(SpotifyUrls.OAuthToken, null, new FormUrlEncodedContent(form), headers);
+    }
+
+    private static APIConnector ValidateConfig(SpotifyClientConfig config)
+    {
+      Ensure.ArgumentNotNull(config, nameof(config));
+      return new APIConnector(
+        config.BaseAddress,
+        config.Authenticator,
+        config.JSONSerializer,
+        config.HTTPClient,
+        config.RetryHandler,
+        config.HTTPLogger
+      );
+    }
+  }
+}

SpotifyAPI.Web/Clients/SpotifyClientConfig.cs

@@ -49,7 +49,7 @@ namespace SpotifyAPI.Web
 
       return new SpotifyClientConfig(
         BaseAddress,
-        new TokenHeaderAuthenticator(token, tokenType),
+        new TokenAuthenticator(token, tokenType),
         JSONSerializer,
         HTTPClient,
         RetryHandler,
@@ -147,7 +147,7 @@ namespace SpotifyAPI.Web
 
     public static SpotifyClientConfig CreateDefault(string token, string tokenType = "Bearer")
     {
-      return CreateDefault().WithAuthenticator(new TokenHeaderAuthenticator(token, tokenType));
+      return CreateDefault().WithAuthenticator(new TokenAuthenticator(token, tokenType));
     }
 
     public static SpotifyClientConfig CreateDefault()

SpotifyAPI.Web/Http/APIConnector.cs

@@ -106,6 +106,13 @@ namespace SpotifyAPI.Web.Http
       return SendAPIRequest<T>(uri, HttpMethod.Post, parameters, body);
     }
 
+    public Task<T> Post<T>(Uri uri, IDictionary<string, string> parameters, object body, Dictionary<string, string> headers)
+    {
+      Ensure.ArgumentNotNull(uri, nameof(uri));
+
+      return SendAPIRequest<T>(uri, HttpMethod.Post, parameters, body, headers);
+    }
+
     public async Task<HttpStatusCode> Post(Uri uri, IDictionary<string, string> parameters, object body)
     {
       Ensure.ArgumentNotNull(uri, nameof(uri));
@@ -160,13 +167,14 @@ namespace SpotifyAPI.Web.Http
         Uri uri,
         HttpMethod method,
         IDictionary<string, string> parameters,
-        object body
+        object body,
+        IDictionary<string, string> headers
       )
     {
       Ensure.ArgumentNotNull(uri, nameof(uri));
       Ensure.ArgumentNotNull(method, nameof(method));
 
-      return new Request(new Dictionary<string, string>(), parameters)
+      return new Request(headers ?? new Dictionary<string, string>(), parameters ?? new Dictionary<string, string>())
       {
         BaseAddress = _baseAddress,
         Endpoint = uri,
@@ -184,7 +192,10 @@ namespace SpotifyAPI.Web.Http
 
     private async Task<IResponse> DoRequest(IRequest request)
     {
-      await _authenticator.Apply(request).ConfigureAwait(false);
+      if (_authenticator != null)
+      {
+        await _authenticator.Apply(request, this).ConfigureAwait(false);
+      }
       _httpLogger?.OnRequest(request);
       IResponse response = await _httpClient.DoRequest(request).ConfigureAwait(false);
       _httpLogger?.OnResponse(response);
@@ -192,7 +203,10 @@ namespace SpotifyAPI.Web.Http
       {
         response = await _retryHandler.HandleRetry(request, response, async (newRequest) =>
         {
-          await _authenticator.Apply(newRequest).ConfigureAwait(false);
+          if (_authenticator != null)
+          {
+            await _authenticator.Apply(request, this).ConfigureAwait(false);
+          }
           var newResponse = await _httpClient.DoRequest(request).ConfigureAwait(false);
           _httpLogger?.OnResponse(newResponse);
           return newResponse;
@@ -206,10 +220,11 @@ namespace SpotifyAPI.Web.Http
         Uri uri,
         HttpMethod method,
         IDictionary<string, string> parameters = null,
-        object body = null
+        object body = null,
+        IDictionary<string, string> headers = null
       )
     {
-      var request = CreateRequest(uri, method, parameters, body);
+      var request = CreateRequest(uri, method, parameters, body, headers);
       return DoRequest(request);
     }
 
@@ -217,10 +232,11 @@ namespace SpotifyAPI.Web.Http
         Uri uri,
         HttpMethod method,
         IDictionary<string, string> parameters = null,
-        object body = null
+        object body = null,
+        IDictionary<string, string> headers = null
       )
     {
-      var request = CreateRequest(uri, method, parameters, body);
+      var request = CreateRequest(uri, method, parameters, body, headers);
       IAPIResponse<T> apiResponse = await DoSerializedRequest<T>(request).ConfigureAwait(false);
       return apiResponse.Body;
     }
@@ -229,10 +245,11 @@ namespace SpotifyAPI.Web.Http
         Uri uri,
         HttpMethod method,
         IDictionary<string, string> parameters = null,
-        object body = null
+        object body = null,
+        IDictionary<string, string> headers = null
       )
     {
-      var request = CreateRequest(uri, method, parameters, body);
+      var request = CreateRequest(uri, method, parameters, body, headers);
       var response = await DoSerializedRequest<object>(request).ConfigureAwait(false);
       return response.Response;
     }

SpotifyAPI.Web/Http/Authenticators/TokenAuthenticator.cs

@@ -2,9 +2,9 @@ using System.Threading.Tasks;
 
 namespace SpotifyAPI.Web.Http
 {
-  public class TokenHeaderAuthenticator : IAuthenticator
+  public class TokenAuthenticator : IAuthenticator
   {
-    public TokenHeaderAuthenticator(string token, string tokenType)
+    public TokenAuthenticator(string token, string tokenType)
     {
       Token = token;
       TokenType = tokenType;
@@ -14,7 +14,7 @@ namespace SpotifyAPI.Web.Http
 
     public string TokenType { get; set; }
 
-    public Task Apply(IRequest request)
+    public Task Apply(IRequest request, IAPIConnector apiConnector)
     {
       Ensure.ArgumentNotNull(request, nameof(request));
 

SpotifyAPI.Web/Http/Interfaces/IAPIConnector.cs

@@ -24,6 +24,7 @@ namespace SpotifyAPI.Web.Http
     Task<T> Post<T>(Uri uri);
     Task<T> Post<T>(Uri uri, IDictionary<string, string> parameters);
     Task<T> Post<T>(Uri uri, IDictionary<string, string> parameters, object body);
+    Task<T> Post<T>(Uri uri, IDictionary<string, string> parameters, object body, Dictionary<string, string> headers);
     Task<HttpStatusCode> Post(Uri uri, IDictionary<string, string> parameters, object body);
 
     Task<T> Put<T>(Uri uri);
@@ -37,7 +38,11 @@ namespace SpotifyAPI.Web.Http
     Task<T> Delete<T>(Uri uri, IDictionary<string, string> parameters, object body);
     Task<HttpStatusCode> Delete(Uri uri, IDictionary<string, string> parameters, object body);
 
-    Task<T> SendAPIRequest<T>(Uri uri, HttpMethod method, IDictionary<string, string> parameters = null, object body = null);
+    Task<T> SendAPIRequest<T>(
+      Uri uri, HttpMethod method,
+      IDictionary<string, string> parameters = null,
+      object body = null,
+      IDictionary<string, string> headers = null);
 
     void SetRequestTimeout(TimeSpan timeout);
   }

SpotifyAPI.Web/Http/Interfaces/IAuthenticator.cs

@@ -4,6 +4,6 @@ namespace SpotifyAPI.Web.Http
 {
   public interface IAuthenticator
   {
-    Task Apply(IRequest request);
+    Task Apply(IRequest request, IAPIConnector apiConnector);
   }
 }

SpotifyAPI.Web/Models/Request/CredentialsRequest.cs

@@ -0,0 +1,16 @@
+namespace SpotifyAPI.Web
+{
+  public class ClientCredentialsRequest
+  {
+    public ClientCredentialsRequest(string clientId, string clientSecret)
+    {
+      Ensure.ArgumentNotNullOrEmptyString(clientId, nameof(clientId));
+      Ensure.ArgumentNotNullOrEmptyString(clientSecret, nameof(clientSecret));
+
+      ClientId = clientId;
+      ClientSecret = clientSecret;
+    }
+    public string ClientId { get; }
+    public string ClientSecret { get; }
+  }
+}

SpotifyAPI.Web/Models/Response/Token.cs

@@ -0,0 +1,9 @@
+namespace SpotifyAPI.Web
+{
+  public class TokenResponse
+  {
+    public string AccessToken { get; set; }
+    public string TokenType { get; set; }
+    public int ExpiresIn { get; set; }
+  }
+}

SpotifyAPI.Web/SpotifyAPI.Web.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.1</TargetFrameworks>
-    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <!-- <GenerateDocumentationFile>true</GenerateDocumentationFile> -->
     <PackageId>SpotifyAPI.Web</PackageId>
     <Title>SpotifyAPI.Web</Title>
     <Authors>Jonas Dellinger</Authors>

SpotifyAPI.Web/SpotifyUrls.cs

@@ -7,6 +7,8 @@ namespace SpotifyAPI.Web
 
     public static readonly Uri APIV1 = new Uri("https://api.spotify.com/v1/");
 
+    public static readonly Uri OAuthToken = new Uri("https://accounts.spotify.com/api/token");
+
     public static Uri Me() => EUri($"me");
 
     public static Uri User(string userId) => EUri($"users/{userId}");