Adds setting to configure leaving stream open (#605)

* Add new boolean setting to flag whether or not to leave stream open

* Use LeaveStreamOpen setting to check whether to dispose StreamReader

* Add new test to validate new LeaveStreamOpen setting

* PR review feedback changes

- Remove default assignment of false boolean to setting
- Code simplification

Co-authored-by: Irvine Sunday <[email protected]>

Author: irvinesunday

src/Microsoft.OpenApi.Readers/OpenApiReaderSettings.cs

@@ -1,5 +1,5 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT license. 
+// Licensed under the MIT license.
 
 using Microsoft.OpenApi.Any;
 using Microsoft.OpenApi.Interfaces;
@@ -61,11 +61,17 @@ public class OpenApiReaderSettings
         public Uri BaseUrl { get; set; }
 
         /// <summary>
-        /// Function used to provide an alternative loader for accessing external references.  
+        /// Function used to provide an alternative loader for accessing external references.
         /// </summary>
         /// <remarks>
         /// Default loader will attempt to dereference http(s) urls and file urls.
         /// </remarks>
         public IStreamLoader CustomExternalLoader { get; set; }
+
+        /// <summary>
+        /// Whether to leave the <see cref="Stream"/> object open after reading
+        /// from an <see cref="OpenApiStreamReader"/> object.
+        /// </summary>
+        public bool LeaveStreamOpen { get; set; }
     }
 }

src/Microsoft.OpenApi.Readers/OpenApiStreamReader.cs

@@ -1,5 +1,5 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT license. 
+// Licensed under the MIT license.
 
 using System.IO;
 using System.Threading.Tasks;
@@ -29,14 +29,18 @@ public OpenApiStreamReader(OpenApiReaderSettings settings = null)
         /// Reads the stream input and parses it into an Open API document.
         /// </summary>
         /// <param name="input">Stream containing OpenAPI description to parse.</param>
-        /// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing</param>
-        /// <returns>Instance of newly created OpenApiDocument</returns>
+        /// <param name="diagnostic">Returns diagnostic object containing errors detected during parsing.</param>
+        /// <returns>Instance of newly created OpenApiDocument.</returns>
         public OpenApiDocument Read(Stream input, out OpenApiDiagnostic diagnostic)
         {
-            using (var reader = new StreamReader(input))
+            var reader = new StreamReader(input);
+            var result = new OpenApiTextReaderReader(_settings).Read(reader, out diagnostic);
+            if (!_settings.LeaveStreamOpen)
             {
-                return new OpenApiTextReaderReader(_settings).Read(reader, out diagnostic);
+                reader.Dispose();
             }
+
+            return result;
         }
 
         /// <summary>
@@ -50,8 +54,8 @@ public async Task<ReadResult> ReadAsync(Stream input)
             if (input is MemoryStream)
             {
                 bufferedStream = (MemoryStream)input;
-            } 
-            else 
+            }
+            else
             {
                 // Buffer stream so that OpenApiTextReaderReader can process it synchronously
                 // YamlDocument doesn't support async reading.

test/Microsoft.OpenApi.Readers.Tests/OpenApiReaderTests/OpenApiStreamReaderTests.cs

@@ -0,0 +1,35 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+using System.IO;
+using Xunit;
+
+namespace Microsoft.OpenApi.Readers.Tests.OpenApiReaderTests
+{
+    public class OpenApiStreamReaderTests
+    {
+        private const string SampleFolderPath = "V3Tests/Samples/OpenApiDocument/";
+
+        [Fact]
+        public void StreamShouldCloseIfLeaveStreamOpenSettingEqualsFalse()
+        {
+            using (var stream = Resources.GetStream(Path.Combine(SampleFolderPath, "petStore.yaml")))
+            {
+                var reader = new OpenApiStreamReader(new OpenApiReaderSettings { LeaveStreamOpen = false });
+                reader.Read(stream, out _);
+                Assert.False(stream.CanRead);
+            }
+        }
+
+        [Fact]
+        public void StreamShouldNotCloseIfLeaveStreamOpenSettingEqualsTrue()
+        {
+            using (var stream = Resources.GetStream(Path.Combine(SampleFolderPath, "petStore.yaml")))
+            {
+                var reader = new OpenApiStreamReader(new OpenApiReaderSettings { LeaveStreamOpen = true});
+                reader.Read(stream, out _);
+                Assert.True(stream.CanRead);
+            }
+        }
+    }
+}