Mastodon APIでのエラーレスポンスの詳細を例外メッセージに含める

Author: upsilon

OpenTween/Api/DataModel/MastodonError.cs

@@ -0,0 +1,32 @@
+// OpenTween - Client of Twitter
+// Copyright (c) 2017 kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
+// All rights reserved.
+//
+// This file is part of OpenTween.
+//
+// This program is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3 of the License, or (at your option)
+// any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+// for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with this program. If not, see <http://www.gnu.org/licenses/>, or write to
+// the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
+// Boston, MA 02110-1301, USA.
+
+using System.Runtime.Serialization;
+
+namespace OpenTween.Api.DataModel
+{
+    [DataContract]
+    public class MastodonError
+    {
+        [DataMember(Name = "error")]
+        public string Error { get; set; }
+    }
+}

OpenTween/Connection/MastodonApiConnection.cs

@@ -23,11 +23,13 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Net;
 using System.Net.Cache;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Runtime.Serialization;
 using System.Threading.Tasks;
+using OpenTween.Api.DataModel;
 
 namespace OpenTween.Connection
 {
@@ -74,7 +76,8 @@ public async Task<T> GetAsync<T>(Uri uri, IEnumerable<KeyValuePair<string, strin
                     using (var response = await this.http.SendAsync(request, HttpCompletionOption.ResponseHeadersRead)
                         .ConfigureAwait(false))
                     {
-                        response.EnsureSuccessStatusCode();
+                        await this.CheckStatusCode(response)
+                            .ConfigureAwait(false);
 
                         using (var content = response.Content)
                         {
@@ -120,7 +123,8 @@ public async Task<Stream> GetStreamAsync(Uri uri, IEnumerable<KeyValuePair<strin
                     using (var response = await this.http.SendAsync(request, HttpCompletionOption.ResponseHeadersRead)
                         .ConfigureAwait(false))
                     {
-                        response.EnsureSuccessStatusCode();
+                        await this.CheckStatusCode(response)
+                            .ConfigureAwait(false);
 
                         return await response.Content.ReadAsStreamAsync().ConfigureAwait(false);
                     }
@@ -162,7 +166,8 @@ public async Task<LazyJson<T>> PostLazyAsync<T>(HttpMethod method, Uri uri, IEnu
                         response = await this.http.SendAsync(request, HttpCompletionOption.ResponseHeadersRead)
                             .ConfigureAwait(false);
 
-                        response.EnsureSuccessStatusCode();
+                        await this.CheckStatusCode(response)
+                            .ConfigureAwait(false);
 
                         var result = new LazyJson<T>(response);
                         response = null;
@@ -191,6 +196,35 @@ public void Dispose()
             this.http.Dispose();
         }
 
+        private async Task CheckStatusCode(HttpResponseMessage response)
+        {
+            var statusCode = response.StatusCode;
+            if (statusCode == HttpStatusCode.OK)
+                return;
+
+            string responseText;
+            using (var content = response.Content)
+            {
+                responseText = await content.ReadAsStringAsync()
+                    .ConfigureAwait(false);
+            }
+
+            if (!string.IsNullOrWhiteSpace(responseText))
+            {
+                try
+                {
+                    var error = MyCommon.CreateDataFromJson<MastodonError>(responseText);
+                    var errorText = error?.Error;
+
+                    if (!string.IsNullOrEmpty(errorText))
+                        throw new WebApiException(errorText, responseText);
+                }
+                catch (SerializationException) { }
+            }
+
+            throw new WebApiException(statusCode.ToString(), responseText);
+        }
+
         private void InitializeHttpClient()
         {
             var innerHandler = Networking.CreateHttpClientHandler();

OpenTween/OpenTween.csproj

@@ -75,6 +75,7 @@
     <Compile Include="Api\DataModel\MastodonAccount.cs" />
     <Compile Include="Api\DataModel\MastodonApplication.cs" />
     <Compile Include="Api\DataModel\MastodonAttachment.cs" />
+    <Compile Include="Api\DataModel\MastodonError.cs" />
     <Compile Include="Api\DataModel\MastodonInstance.cs" />
     <Compile Include="Api\DataModel\MastodonMention.cs" />
     <Compile Include="Api\DataModel\MastodonRegisteredApp.cs" />