GatewayClientStore: Fixes an issue with dealing with invalid JSON HTTP responses

Microsoft.Azure.Cosmos/src/GatewayStoreClient.cs

@@ -9,6 +9,7 @@ namespace Microsoft.Azure.Cosmos
     using System.Diagnostics;
     using System.Diagnostics.CodeAnalysis;
     using System.IO;
+    using System.Linq;
     using System.Net.Http;
     using System.Net.Http.Headers;
     using System.Text;
@@ -19,6 +20,7 @@ namespace Microsoft.Azure.Cosmos
     using Microsoft.Azure.Documents;
     using Microsoft.Azure.Documents.Collections;
     using Newtonsoft.Json;
+    using Newtonsoft.Json.Linq;
 
     internal class GatewayStoreClient : TransportClient
     {
@@ -150,8 +152,23 @@ internal static INameValueCollection ExtractResponseHeaders(HttpResponseMessage
             // If service rejects the initial payload like header is to large it will return an HTML error instead of JSON.
             if (string.Equals(responseMessage.Content?.Headers?.ContentType?.MediaType, "application/json", StringComparison.OrdinalIgnoreCase))
             {
-                Stream readStream = await responseMessage.Content.ReadAsStreamAsync();
-                Error error = Documents.Resource.LoadFrom<Error>(readStream);
+                // For more information, see https://github.com/Azure/azure-cosmos-dotnet-v3/issues/4162.
+                Error error;
+
+                if (await GatewayStoreClient.IsJsonHTTPResponseFromGatewayInvalidAsync(responseMessage))
+                {
+                    error = new Error
+                    {
+                        Code = responseMessage.StatusCode.ToString(),
+                        Message = "No response content from gateway."
+                    };
+                }
+                else
+                {
+                    Stream readStream = await responseMessage.Content.ReadAsStreamAsync();
+                    error = Documents.Resource.LoadFrom<Error>(readStream);
+                }
+
                 return new DocumentClientException(
                     error,
                     responseMessage.Headers,
@@ -197,6 +214,29 @@ internal static INameValueCollection ExtractResponseHeaders(HttpResponseMessage
             }
         }
 
+        /// <summary>
+        /// Checking if exception response (deserializable Error object) is valid based on the content length.
+        /// For more information, see <see href="https://github.com/Azure/azure-cosmos-dotnet-v3/issues/4162."/>.
+        /// </summary>
+        /// <param name="responseMessage"></param>
+        private static async Task<bool> IsJsonHTTPResponseFromGatewayInvalidAsync(HttpResponseMessage responseMessage)
+        {
+            string readString = await responseMessage.Content.ReadAsStringAsync();
+
+            try
+            {
+                _ = JToken.Parse(readString);
+
+                return responseMessage.Content?.Headers?.ContentLength == 0 ||
+                    readString.Trim().Length == 0;
+            }
+            catch (JsonReaderException)
+            {
+                return true;
+            }
+
+        }
+
         internal static bool IsAllowedRequestHeader(string headerName)
         {
             if (!headerName.StartsWith("x-ms", StringComparison.OrdinalIgnoreCase))

Microsoft.Azure.Cosmos/tests/Microsoft.Azure.Cosmos.Tests/GatewayStoreClientTests.cs

@@ -0,0 +1,106 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+namespace Microsoft.Azure.Cosmos
+{
+    using System;
+    using System.Net;
+    using System.Net.Http;
+    using System.Threading.Tasks;
+    using Microsoft.Azure.Cosmos.Tracing;
+    using Microsoft.Azure.Cosmos.Tracing.TraceData;
+    using Microsoft.Azure.Documents;
+    using Microsoft.VisualStudio.TestTools.UnitTesting;
+    using Newtonsoft.Json;
+
+    /// <summary>
+    /// Tests for <see cref="GatewayStoreClient"/>.
+    /// </summary>
+    [TestClass]
+    public class GatewayStoreClientTests
+    {
+        /// <summary>
+        /// Testing the exception behavior when a response from the Gateway has no response (deserializable Error object) based on the content length.
+        /// For more information, see <see href="https://github.com/Azure/azure-cosmos-dotnet-v3/issues/4162"/>.
+        /// </summary>
+        /// <returns></returns>
+        [TestMethod]
+        [DataRow(@"")]
+        [DataRow(@"    ")]
+        [DataRow(@"<!DOCTYPE html><html><body></body></html>")]
+        [DataRow(@"   <!DOCTYPE html><html><body></body></html>")]
+        [DataRow(@"<!DOCTYPE html><html><body></body></html>   ")]
+        [DataRow(@"   <!DOCTYPE html><html><body></body></html>   ")]
+        [DataRow(@"ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")]
+        [DataRow(@"   ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890")]
+        [DataRow(@"ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890   ")]
+        [DataRow(@"   ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890   ")]
+        public async Task CreateDocumentClientExceptionInvalidJsonResponseFromGatewayTestAsync(string content)
+        {
+            HttpResponseMessage responseMessage = new(statusCode: System.Net.HttpStatusCode.NotFound)
+            {
+                RequestMessage = new HttpRequestMessage(
+                    method: HttpMethod.Get,
+                    requestUri: @"https://pt_ac_test_uri.com/"),
+                Content = new StringContent(
+                    content: content),
+            };
+
+            responseMessage.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");
+
+            IClientSideRequestStatistics requestStatistics = new ClientSideRequestStatisticsTraceDatum(
+                startTime: DateTime.UtcNow, 
+                trace: NoOpTrace.Singleton);
+
+            DocumentClientException documentClientException = await GatewayStoreClient.CreateDocumentClientExceptionAsync(
+                responseMessage: responseMessage,
+                requestStatistics: requestStatistics);
+
+            Assert.IsNotNull(value: documentClientException);
+            Assert.AreEqual(expected: HttpStatusCode.NotFound, actual: documentClientException.StatusCode);
+            Assert.IsTrue(condition: documentClientException.Message.Contains("No response content from gateway."));
+
+            Assert.IsNotNull(value: documentClientException.Error);
+            Assert.AreEqual(expected: HttpStatusCode.NotFound.ToString(), actual: documentClientException.Error.Code);
+            Assert.AreEqual(expected: "No response content from gateway.", actual: documentClientException.Error.Message);
+        }
+
+        /// <summary>
+        /// Testing the exception behavior when a response from the Gateway has a response (deserializable Error object) based the content length.
+        /// For more information, see <see href="https://github.com/Azure/azure-cosmos-dotnet-v3/issues/4162"/>.
+        /// </summary>
+        /// <returns></returns>
+        [TestMethod]
+        [DataRow(@"This is the content of a test error message.")]
+        public async Task CreateDocumentClientExceptionValidJsonResponseFromGatewayTestAsync(string content)
+        {
+            HttpResponseMessage responseMessage = new(statusCode: System.Net.HttpStatusCode.NotFound)
+            {
+                RequestMessage = new HttpRequestMessage(
+                    method: HttpMethod.Get,
+                    requestUri: @"https://pt_ac_test_uri.com/"),
+                Content = new StringContent(
+                    content: JsonConvert.SerializeObject(
+                        value: new Error() { Code = HttpStatusCode.NotFound.ToString(), Message = content })),
+            };
+
+            responseMessage.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/json");
+
+            IClientSideRequestStatistics requestStatistics = new ClientSideRequestStatisticsTraceDatum(
+                startTime: DateTime.UtcNow,
+                trace: NoOpTrace.Singleton);
+
+            DocumentClientException documentClientException = await GatewayStoreClient.CreateDocumentClientExceptionAsync(
+                responseMessage: responseMessage,
+                requestStatistics: requestStatistics);
+
+            Assert.IsNotNull(value: documentClientException);
+            Assert.AreEqual(expected: HttpStatusCode.NotFound, actual: documentClientException.StatusCode);
+            Assert.IsTrue(condition: documentClientException.Message.Contains(content));
+
+            Assert.IsNotNull(value: documentClientException.Error);
+            Assert.AreEqual(expected: HttpStatusCode.NotFound.ToString(), actual: documentClientException.Error.Code);
+            Assert.AreEqual(expected: content, actual: documentClientException.Error.Message);
+        }
+    }
+}