Add AzureSasCredential

sdk/core/Azure.Core/api/Azure.Core.net461.cs

@@ -22,6 +22,13 @@ public AzureKeyCredential(string key) { }
         public string Key { get { throw null; } }
         public void Update(string key) { }
     }
+    public partial class AzureSasCredential
+    {
+        public AzureSasCredential(string signature) { }
+        [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        public string Signature { get { throw null; } }
+        public void Update(string signature) { }
+    }
     [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
     public readonly partial struct ETag : System.IEquatable<Azure.ETag>
     {

sdk/core/Azure.Core/api/Azure.Core.net5.0.cs

@@ -22,6 +22,13 @@ public AzureKeyCredential(string key) { }
         public string Key { get { throw null; } }
         public void Update(string key) { }
     }
+    public partial class AzureSasCredential
+    {
+        public AzureSasCredential(string signature) { }
+        [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        public string Signature { get { throw null; } }
+        public void Update(string signature) { }
+    }
     [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
     public readonly partial struct ETag : System.IEquatable<Azure.ETag>
     {

sdk/core/Azure.Core/api/Azure.Core.netstandard2.0.cs

@@ -22,6 +22,13 @@ public AzureKeyCredential(string key) { }
         public string Key { get { throw null; } }
         public void Update(string key) { }
     }
+    public partial class AzureSasCredential
+    {
+        public AzureSasCredential(string signature) { }
+        [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
+        public string Signature { get { throw null; } }
+        public void Update(string signature) { }
+    }
     [System.Runtime.InteropServices.StructLayoutAttribute(System.Runtime.InteropServices.LayoutKind.Sequential)]
     public readonly partial struct ETag : System.IEquatable<Azure.ETag>
     {

sdk/core/Azure.Core/src/Azure.Core.csproj

@@ -26,6 +26,7 @@
     <Compile Remove="Shared\**\*.cs" />
     <Compile Include="Shared\Argument.cs" />
     <Compile Include="Shared\AzureKeyCredentialPolicy.cs" />
+    <Compile Include="Shared\AzureSasCredentialPolicy.cs" />
     <Compile Include="Shared\EventSourceEventFormatting.cs" />
     <Compile Include="Shared\HashCodeBuilder.cs" />
     <Compile Include="Shared\ClientDiagnostics.cs" />

sdk/core/Azure.Core/src/AzureSasCredential.cs

@@ -0,0 +1,60 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.ComponentModel;
+using System.Threading;
+using Azure.Core;
+
+namespace Azure
+{
+    /// <summary>
+    /// Shared access signature credential used to authenticate to an Azure Service.
+    /// It provides the ability to update the signature without creating a new client.
+    /// </summary>
+    public class AzureSasCredential
+    {
+        private string _signature;
+
+        /// <summary>
+        /// Signature used to authenticate to an Azure service.
+        /// </summary>
+        [EditorBrowsable(EditorBrowsableState.Never)]
+        public string Signature
+        {
+            get => Volatile.Read(ref _signature);
+            private set => Volatile.Write(ref _signature, value);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AzureSasCredential"/> class.
+        /// </summary>
+        /// <param name="signature">Signature to use to authenticate with the Azure service.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// Thrown when the <paramref name="signature"/> is null.
+        /// </exception>
+        /// <exception cref="System.ArgumentException">
+        /// Thrown when the <paramref name="signature"/> is empty.
+        /// </exception>
+#pragma warning disable CS8618 // Non-nullable field is uninitialized. Consider declaring as nullable.
+        public AzureSasCredential(string signature) => Update(signature);
+#pragma warning restore CS8618 // Non-nullable field is uninitialized. Consider declaring as nullable.
+
+        /// <summary>
+        /// Updates the signature.
+        /// This is intended to be used when you've regenerated your signature
+        /// and want to update long lived clients.
+        /// </summary>
+        /// <param name="signature">Signature to authenticate the service against.</param>
+        /// <exception cref="System.ArgumentNullException">
+        /// Thrown when the <paramref name="signature"/> is null.
+        /// </exception>
+        /// <exception cref="System.ArgumentException">
+        /// Thrown when the <paramref name="signature"/> is empty.
+        /// </exception>
+        public void Update(string signature)
+        {
+            Argument.AssertNotNullOrEmpty(signature, nameof(signature));
+            Signature = signature;
+        }
+    }
+}

sdk/core/Azure.Core/src/Shared/AzureSasCredentialPolicy.cs

@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using Azure.Core.Pipeline;
+
+namespace Azure.Core
+{
+    internal class AzureSasCredentialPolicy : HttpPipelineSynchronousPolicy
+    {
+        private readonly AzureSasCredential _credential;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AzureSasCredentialPolicy"/> class.
+        /// </summary>
+        /// <param name="credential">The <see cref="AzureSasCredentialPolicy"/> used to authenticate requests.</param>
+        public AzureSasCredentialPolicy(AzureSasCredential credential)
+        {
+            Argument.AssertNotNull(credential, nameof(credential));
+            _credential = credential;
+        }
+
+        /// <inheritdoc/>
+        public override void OnSendingRequest(HttpMessage message)
+        {
+            base.OnSendingRequest(message);
+            string query = message.Request.Uri.Query;
+            string signature = _credential.Signature;
+            if (signature.StartsWith("?", StringComparison.InvariantCulture))
+            {
+                signature = signature.Substring(1);
+            }
+            if (!query.Contains(signature))
+            {
+                query = string.IsNullOrEmpty(query) ? '?' + signature : query + '&' + signature;
+                message.Request.Uri.Query = query;
+            }
+        }
+    }
+}

sdk/core/Azure.Core/tests/AzureSasCredentialPolicyTests.cs

@@ -0,0 +1,77 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Azure.Core.Pipeline;
+using Azure.Core.TestFramework;
+using NUnit.Framework;
+
+namespace Azure.Core.Tests
+{
+    public class AzureSasCredentialPolicyTests : PolicyTestBase
+    {
+        [TestCase("sig=test_signature_value")]
+        [TestCase("?sig=test_signature_value")]
+        public async Task SetsSignatureEmptyQuery(string signatureValue)
+        {
+            var transport = new MockTransport(new MockResponse(200));
+            var sasPolicy = new AzureSasCredentialPolicy(new AzureSasCredential(signatureValue));
+
+            await SendGetRequest(transport, sasPolicy);
+
+            Assert.AreEqual("?sig=test_signature_value", transport.SingleRequest.Uri.Query);
+        }
+
+        [TestCase("sig=test_signature_value")]
+        [TestCase("?sig=test_signature_value")]
+        public async Task SetsSignatureNonEmptyQuery(string signatureValue)
+        {
+            var transport = new MockTransport(new MockResponse(200));
+            var sasPolicy = new AzureSasCredentialPolicy(new AzureSasCredential(signatureValue));
+            string query = "?foo=bar";
+
+            await SendGetRequest(transport, sasPolicy, query: query);
+
+            Assert.AreEqual($"?foo=bar&sig=test_signature_value", transport.SingleRequest.Uri.Query);
+        }
+
+        [TestCase("sig=test_signature_value")]
+        [TestCase("?sig=test_signature_value")]
+        public async Task VerifyRetryEmptyQuery(string signatureValue)
+        {
+            var transport = new MockTransport(new MockResponse(200), new MockResponse(200));
+            var sasPolicy = new AzureSasCredentialPolicy(new AzureSasCredential(signatureValue));
+
+            using (Request request = transport.CreateRequest())
+            {
+                request.Method = RequestMethod.Get;
+                var pipeline = new HttpPipeline(transport, new[] { sasPolicy });
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+            }
+
+            Assert.AreEqual("?sig=test_signature_value", transport.Requests[0].Uri.Query);
+        }
+
+        [TestCase("sig=test_signature_value")]
+        [TestCase("?sig=test_signature_value")]
+        public async Task VerifyRetryNonEmptyQuery(string signatureValue)
+        {
+            var transport = new MockTransport(new MockResponse(200), new MockResponse(200));
+            var sasPolicy = new AzureSasCredentialPolicy(new AzureSasCredential(signatureValue));
+            string query = "?foo=bar";
+
+            using (Request request = transport.CreateRequest())
+            {
+                request.Method = RequestMethod.Get;
+                request.Uri.Query = query;
+                var pipeline = new HttpPipeline(transport, new[] { sasPolicy });
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+                await pipeline.SendRequestAsync(request, CancellationToken.None);
+            }
+
+            Assert.AreEqual("?foo=bar&sig=test_signature_value", transport.Requests[0].Uri.Query);
+        }
+    }
+}

sdk/core/Azure.Core/tests/PolicyTestBase.cs

@@ -11,14 +11,15 @@ namespace Azure.Core.Tests
 {
     public abstract class PolicyTestBase
     {
-        protected static async Task<Response> SendGetRequest(HttpPipelineTransport transport, HttpPipelinePolicy policy, ResponseClassifier responseClassifier = null)
+        protected static async Task<Response> SendGetRequest(HttpPipelineTransport transport, HttpPipelinePolicy policy, ResponseClassifier responseClassifier = null, string query = null)
         {
             Assert.IsInstanceOf<HttpPipelineSynchronousPolicy>(policy, "Use SyncAsyncPolicyTestBase base type for non-sync policies");
 
             using (Request request = transport.CreateRequest())
             {
                 request.Method = RequestMethod.Get;
                 request.Uri.Reset(new Uri("http://example.com"));
+                request.Uri.Query = query;
                 var pipeline = new HttpPipeline(transport, new[] { policy }, responseClassifier);
                 return await pipeline.SendRequestAsync(request, CancellationToken.None);
             }