Requesting detailed error responses from FCM backend (#107)

Author: hiranya911

FirebaseAdmin/FirebaseAdmin.Tests/Messaging/FirebaseMessagingClientTest.cs

@@ -16,6 +16,7 @@
 using System.Linq;
 using System.Net;
 using System.Net.Http;
+using System.Net.Http.Headers;
 using System.Threading.Tasks;
 using FirebaseAdmin.Tests;
 using Google.Apis.Auth.OAuth2;
@@ -30,6 +31,12 @@ public class FirebaseMessagingClientTest
         private static readonly GoogleCredential MockCredential =
             GoogleCredential.FromAccessToken("test-token");
 
+        private static readonly string VersionHeader =
+            $"X-Firebase-Client: {FirebaseMessagingClient.ClientVersion}";
+
+        private static readonly string ApiFormatHeader =
+            "X-GOOG-API-FORMAT-VERSION: 2";
+
         [Fact]
         public void NoProjectId()
         {
@@ -80,8 +87,7 @@ public async Task SendAsync()
             Assert.Equal("test-topic", req.Message.Topic);
             Assert.False(req.ValidateOnly);
             Assert.Equal(1, handler.Calls);
-            var versionHeader = handler.LastRequestHeaders.GetValues("X-Firebase-Client").First();
-            Assert.Equal(FirebaseMessagingClient.ClientVersion, versionHeader);
+            this.CheckHeaders(handler.LastRequestHeaders);
         }
 
         [Fact]
@@ -108,8 +114,7 @@ public async Task SendDryRunAsync()
             Assert.Equal("test-topic", req.Message.Topic);
             Assert.True(req.ValidateOnly);
             Assert.Equal(1, handler.Calls);
-            var versionHeader = handler.LastRequestHeaders.GetValues("X-Firebase-Client").First();
-            Assert.Equal(FirebaseMessagingClient.ClientVersion, versionHeader);
+            this.CheckHeaders(handler.LastRequestHeaders);
         }
 
         [Fact]
@@ -172,8 +177,9 @@ public async Task SendAllAsync()
             Assert.Equal("projects/fir-adminintegrationtests/messages/8580920590356323124", response.Responses[0].MessageId);
             Assert.Equal("projects/fir-adminintegrationtests/messages/5903525881088369386", response.Responses[1].MessageId);
             Assert.Equal(1, handler.Calls);
-            var versionHeader = $"X-Firebase-Client: {FirebaseMessagingClient.ClientVersion}";
-            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, versionHeader));
+
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, VersionHeader));
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, ApiFormatHeader));
         }
 
         [Fact]
@@ -254,8 +260,8 @@ public async Task SendAllAsyncWithError()
             Assert.NotNull(exception.HttpResponse);
 
             Assert.Equal(1, handler.Calls);
-            var versionHeader = $"X-Firebase-Client: {FirebaseMessagingClient.ClientVersion}";
-            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, versionHeader));
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, VersionHeader));
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, ApiFormatHeader));
         }
 
         [Fact]
@@ -327,8 +333,8 @@ public async Task SendAllAsyncWithErrorNoDetail()
             Assert.NotNull(exception.HttpResponse);
 
             Assert.Equal(1, handler.Calls);
-            var versionHeader = $"X-Firebase-Client: {FirebaseMessagingClient.ClientVersion}";
-            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, versionHeader));
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, VersionHeader));
+            Assert.Equal(2, this.CountLinesWithPrefix(handler.LastRequestBody, ApiFormatHeader));
         }
 
         [Fact]
@@ -497,6 +503,15 @@ public async Task TransportError()
             Assert.Equal(1, handler.Calls);
         }
 
+        private void CheckHeaders(HttpRequestHeaders header)
+        {
+            var versionHeader = header.GetValues("X-Firebase-Client").First();
+            Assert.Equal(FirebaseMessagingClient.ClientVersion, versionHeader);
+
+            var apiFormatHeader = header.GetValues("X-GOOG-API-FORMAT-VERSION").First();
+            Assert.Equal("2", apiFormatHeader);
+        }
+
         private int CountLinesWithPrefix(string body, string linePrefix)
         {
             return body.Split('\n').Count((line) => line.StartsWith(linePrefix));

FirebaseAdmin/FirebaseAdmin/Messaging/FirebaseMessagingClient.cs

@@ -174,6 +174,7 @@ public void Dispose()
         private static void AddCommonHeaders(HttpRequestMessage request)
         {
             request.Headers.Add("X-Firebase-Client", ClientVersion);
+            request.Headers.Add("X-GOOG-API-FORMAT-VERSION", "2");
         }
 
         private async Task<BatchResponse> SendBatchRequestAsync(