Add ability to bind to a string value body message. (Azure#20378)

* Add ability to bind to a string value body message.

* PR FB

Author: JoshLove-msft

sdk/servicebus/Microsoft.Azure.WebJobs.Extensions.ServiceBus/src/Triggers/MessageToStringConverter.cs

@@ -2,71 +2,69 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
-using System.Globalization;
 using System.IO;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
+using Azure.Core.Amqp;
 using Azure.Messaging.ServiceBus;
 using Microsoft.Azure.WebJobs.Extensions.ServiceBus.Triggers;
 
 namespace Microsoft.Azure.WebJobs.ServiceBus.Triggers
 {
-    internal class MessageToStringConverter : IAsyncConverter<ServiceBusReceivedMessage, string>
+    internal class MessageToStringConverter : IConverter<ServiceBusReceivedMessage, string>
     {
-        public async Task<string> ConvertAsync(ServiceBusReceivedMessage input, CancellationToken cancellationToken)
+        public string Convert(ServiceBusReceivedMessage input)
         {
             if (input == null)
             {
                 throw new ArgumentNullException(nameof(input));
             }
-            if (input.Body == null)
-            {
-                return null;
-            }
-
-            Stream stream = input.Body.ToStream();
 
-            TextReader reader = new StreamReader(stream, StrictEncodings.Utf8);
-            try
+            var body = input.GetRawAmqpMessage().Body;
+            if (body.BodyType == AmqpMessageBodyType.Data)
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (input.Body == null)
+                {
+                    return null;
+                }
+
                 try
                 {
-                    return await reader.ReadToEndAsync().ConfigureAwait(false);
+                    return StrictEncodings.Utf8.GetString(input.Body.ToArray());
                 }
                 catch (DecoderFallbackException)
                 {
                     // we'll try again below
                 }
 
-                // We may get here if the message is a string yet was DataContract-serialized when created. We'll
-                // try to deserialize it here using GetBody<string>(). This may fail as well, in which case we'll
-                // provide a decent error.
-
+                // We may get here if the message is a string yet was DataContract-serialized when created.
                 try
                 {
+                    using Stream stream = input.Body.ToStream();
                     var serializer = DataContractBinarySerializer<string>.Instance;
                     stream.Position = 0;
-                    return (string)serializer.ReadObject(stream);
+                    return (string) serializer.ReadObject(stream);
                 }
                 catch
                 {
                     // always possible to get a valid string from the message
                     return input.Body.ToString();
                 }
             }
-            finally
+            else if (body.BodyType == AmqpMessageBodyType.Value)
             {
-                if (stream != null)
-                {
-                    stream.Dispose();
-                }
-                if (reader != null)
+                body.TryGetValue(out object value);
+                if (value is string stringValue)
                 {
-                    reader.Dispose();
+                    return stringValue;
                 }
+
+                throw new NotSupportedException(
+                    $"A message with a body of type {value?.GetType()} cannot be bound to a string.");
+            }
+            else
+            {
+                throw new NotSupportedException("A sequence body message cannot be bound to a string.");
             }
         }
     }
-}
+}

sdk/servicebus/Microsoft.Azure.WebJobs.Extensions.ServiceBus/tests/MessageToStringConverterTests.cs

@@ -2,10 +2,12 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using Azure.Core.Amqp;
 using Microsoft.Azure.WebJobs.ServiceBus.Triggers;
 using NUnit.Framework;
 using Azure.Messaging.ServiceBus;
@@ -25,7 +27,7 @@ public class MessageToStringConverterTests
         [TestCase(null, TestJson)]
         [TestCase("application/xml", TestJson)]
         [TestCase(ContentTypes.TextPlain, null)]
-        public async Task ConvertAsync_ReturnsExpectedResult_WithBinarySerializer(string contentType, string value)
+        public void Convert_ReturnsExpectedResult_WithBinarySerializer(string contentType, string value)
         {
             byte[] bytes;
             using (MemoryStream ms = new MemoryStream())
@@ -37,7 +39,7 @@ public async Task ConvertAsync_ReturnsExpectedResult_WithBinarySerializer(string
             ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage(body: new BinaryData(bytes), contentType: contentType);
 
             MessageToStringConverter converter = new MessageToStringConverter();
-            string result = await converter.ConvertAsync(message, CancellationToken.None);
+            string result = converter.Convert(message);
 
             Assert.AreEqual(value, result);
         }
@@ -50,14 +52,14 @@ public async Task ConvertAsync_ReturnsExpectedResult_WithBinarySerializer(string
         [TestCase("application/xml", TestJson)]
         [TestCase(ContentTypes.TextPlain, null)]
         [TestCase(ContentTypes.TextPlain, "")]
-        public async Task ConvertAsync_ReturnsExpectedResult_WithSerializedString(string contentType, string value)
+        public void Convert_ReturnsExpectedResult_WithSerializedString(string contentType, string value)
         {
             ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage(
                 body: value == null ? null : new BinaryData(value),
                 contentType: contentType);
 
             MessageToStringConverter converter = new MessageToStringConverter();
-            string result = await converter.ConvertAsync(message, CancellationToken.None);
+            string result = converter.Convert(message);
             // A received message will never have a null body as a body section is required when sending even if it
             // is empty. This was true in Track 1 as well, but in Track 1 the actual body property could be null when
             // constructing the message, but in practice it wouldn't be null when receiving.
@@ -72,7 +74,7 @@ public async Task ConvertAsync_ReturnsExpectedResult_WithSerializedString(string
         }
 
         [Test]
-        public async Task ConvertAsync_ReturnsExpectedResult_WithSerializedObject()
+        public void Convert_ReturnsExpectedResult_WithSerializedObject()
         {
             byte[] bytes;
             using (MemoryStream ms = new MemoryStream())
@@ -84,10 +86,45 @@ public async Task ConvertAsync_ReturnsExpectedResult_WithSerializedObject()
             ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage(body: new BinaryData(bytes));
 
             MessageToStringConverter converter = new MessageToStringConverter();
-            string result = await converter.ConvertAsync(message, CancellationToken.None);
+            string result = converter.Convert(message);
             Assert.AreEqual(message.Body.ToString(), result);
         }
 
+        [Test]
+        public void Convert_ValueBodyMessage_String()
+        {
+            ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage();
+            message.GetRawAmqpMessage().Body = AmqpMessageBody.FromValue("value");
+
+            MessageToStringConverter converter = new MessageToStringConverter();
+            string result = converter.Convert(message);
+            Assert.AreEqual("value", result);
+        }
+
+        [Test]
+        public void Convert_ValueBodyMessage_NonStringThrows()
+        {
+            ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage();
+            message.GetRawAmqpMessage().Body = AmqpMessageBody.FromValue(5);
+
+            MessageToStringConverter converter = new MessageToStringConverter();
+            Assert.That(
+                () => converter.Convert(message),
+                Throws.InstanceOf<NotSupportedException>());
+        }
+
+        [Test]
+        public void Convert_SequenceBodyMessage_Throws()
+        {
+            ServiceBusReceivedMessage message = ServiceBusModelFactory.ServiceBusReceivedMessage();
+            message.GetRawAmqpMessage().Body = AmqpMessageBody.FromSequence(new IList<object>[]{ new object[] {"sequence"}});
+
+            MessageToStringConverter converter = new MessageToStringConverter();
+            Assert.That(
+                () => converter.Convert(message),
+                Throws.InstanceOf<NotSupportedException>());
+        }
+
         [Serializable]
         public class TestObject
         {