Add controller base extensions to get set callback data

src/Ztm.WebApi.Tests/Controllers/ControllerBaseExtensionsTests.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Net;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Xunit;
+using Ztm.WebApi.Controllers;
+
+namespace Ztm.WebApi.Tests.Controllers
+{
+    public sealed class ControllerBaseExtensionsTests
+    {
+        readonly static string CallbackUrlKey = "X-Callback-URL";
+        readonly static string CallbackIdKey = "X-Callback-ID";
+
+        readonly ControllerBase subject;
+
+        public ControllerBaseExtensionsTests()
+        {
+            this.subject = new TestControllerBase();
+            this.subject.ControllerContext.HttpContext = new DefaultHttpContext();
+        }
+
+        [Theory]
+        [InlineData("http://zcoin.io/")]
+        [InlineData("https://zcoin.io/")]
+        public void TryGetCallbackUrl_WithValidUrl_ShouldSuccess(string rawUrl)
+        {
+            // Arrange.
+            this.subject.HttpContext.Request.Headers.Add(CallbackUrlKey, rawUrl);
+
+            // Act.
+            var success = this.subject.TryGetCallbackUrl(out var url);
+
+            // Assert.
+            Assert.True(success);
+            Assert.Equal(new Uri(rawUrl), url);
+        }
+
+        [Theory]
+        [InlineData("urn:isbn:0451450523")]
+        [InlineData("urn:lsid:zoobank.org:pub:CDC8D258-8F57-41DC-B560-247E17D3DC8C")]
+        [InlineData("Foo")]
+        public void TryGetCallbackUrl_WithInvalidUrl_ShouldReturnFalse(string invalidUrl)
+        {
+            // Arrange.
+            this.subject.HttpContext.Request.Headers.Add(CallbackUrlKey, invalidUrl);
+
+            // Act.
+            var success = this.subject.TryGetCallbackUrl(out var url);
+
+            // Assert.
+            Assert.False(success);
+            Assert.Null(url);
+        }
+
+        [Fact]
+        public void TryGetCallbackUrl_WithUnsetHeader_ShouldReturnFalse()
+        {
+            // Act.
+            var success = this.subject.TryGetCallbackUrl(out var url);
+
+            // Assert.
+            Assert.False(success);
+            Assert.Null(url);
+        }
+
+        [Fact]
+        public void SetCallbackId_WithValidGuid_ShouldSuccess()
+        {
+            // Arrange.
+            var id = Guid.NewGuid();
+
+            // Act.
+            this.subject.SetCallbackId(id);
+
+            // Assert.
+            Assert.True(
+                this.subject.HttpContext.Response.Headers.TryGetValue(CallbackIdKey, out var retreived)
+            );
+            Assert.Equal(id.ToString(), retreived);
+            Assert.Equal(this.subject.HttpContext.Response.StatusCode, (int)HttpStatusCode.Accepted);
+        }
+    }
+
+    class TestControllerBase : ControllerBase
+    {
+    }
+}

src/Ztm.WebApi/Controllers/ControllerBaseExtensions.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Net;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Ztm.WebApi.Controllers
+{
+    public static class ControllerBaseExtensions
+    {
+        readonly static string CallbackUrlKey = "X-Callback-URL";
+        readonly static string CallbackIdKey = "X-Callback-ID";
+
+        public static bool TryGetCallbackUrl(this ControllerBase controller, out Uri url)
+        {
+            if (controller.HttpContext.Request.Headers.TryGetValue(CallbackUrlKey, out var rawUrl))
+            {
+                try
+                {
+                    url = new Uri(rawUrl);
+
+                    if (url.Scheme == Uri.UriSchemeHttp
+                        || url.Scheme == Uri.UriSchemeHttps)
+                    {
+                        return true;
+                    }
+                }
+                catch (UriFormatException)
+                {
+                }
+            }
+
+            url = null;
+            return false;
+        }
+
+        public static void SetCallbackId(this ControllerBase controller, Guid id)
+        {
+            controller.HttpContext.Response.Headers.Add(CallbackIdKey, id.ToString());
+            controller.HttpContext.Response.StatusCode = (int)HttpStatusCode.Accepted;
+        }
+    }
+}