Convert the static UriHelper into a service, IUriHelper, and inject where needed

src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Platform/Mono/MonoPlatform.ts

@@ -34,7 +34,7 @@ export const monoPlatform: Platform = {
 
     const typeHandle = find_class(assemblyHandle, namespace, className);
     if (!typeHandle) {
-      throw new Error(`Could not find type "${className}'" in namespace "${namespace}" in assembly "${assemblyName}"`);
+      throw new Error(`Could not find type "${className}" in namespace "${namespace}" in assembly "${assemblyName}"`);
     }
 
     const methodHandle = find_method(typeHandle, methodName, -1);

src/Microsoft.AspNetCore.Blazor.Browser.JS/src/Routing/UriHelper.ts

@@ -1,7 +1,7 @@
 import { registerFunction } from '../Interop/RegisteredFunction';
 import { platform } from '../Environment';
 import { MethodHandle } from '../Platform/Platform';
-const registeredFunctionPrefix = 'Microsoft.AspNetCore.Blazor.Browser.Routing.UriHelper';
+const registeredFunctionPrefix = 'Microsoft.AspNetCore.Blazor.Browser.Services.BrowserUriHelper';
 let notifyLocationChangedMethod: MethodHandle;
 let hasRegisteredEventListeners = false;
 
@@ -37,8 +37,8 @@ function handleInternalNavigation() {
   if (!notifyLocationChangedMethod) {
     notifyLocationChangedMethod = platform.findMethod(
       'Microsoft.AspNetCore.Blazor.Browser',
-      'Microsoft.AspNetCore.Blazor.Browser.Routing',
+      'Microsoft.AspNetCore.Blazor.Browser.Services',
-      'UriHelper',
+      'BrowserUriHelper',
       'NotifyLocationChanged'
     );
   }

src/Microsoft.AspNetCore.Blazor.Browser/Routing/BrowserRouter.cs

@@ -7,6 +7,7 @@ using System.Reflection;
 using Microsoft.AspNetCore.Blazor.Components;
 using Microsoft.AspNetCore.Blazor.Layouts;
 using Microsoft.AspNetCore.Blazor.RenderTree;
+using Microsoft.AspNetCore.Blazor.Services;
 
 namespace Microsoft.AspNetCore.Blazor.Browser.Routing
 {
@@ -22,6 +23,8 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
         string _baseUriPrefix;
         string _locationAbsolute;
 
+        [Inject] private IUriHelper UriHelper { get; set; }
+
         /// <summary>
         /// Gets or sets the assembly that should be searched, along with its referenced
         /// assemblies, for components matching the URI.

src/Microsoft.AspNetCore.Blazor.Browser/Routing/NavLink.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.AspNetCore.Blazor.Components;
 using Microsoft.AspNetCore.Blazor.RenderTree;
+using Microsoft.AspNetCore.Blazor.Services;
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -32,6 +33,8 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
         private string _hrefAbsolute;
         private IReadOnlyDictionary<string, object> _allAttributes;
 
+        [Inject] private IUriHelper UriHelper { get; set; }
+
         public void Init(RenderHandle renderHandle)
         {
             _renderHandle = renderHandle;

src/Microsoft.AspNetCore.Blazor.Browser/Services/BrowserUriHelper.cs

@@ -2,28 +2,31 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using Microsoft.AspNetCore.Blazor.Browser.Interop;
+using Microsoft.AspNetCore.Blazor.Services;
 using System;
 
-namespace Microsoft.AspNetCore.Blazor.Browser.Routing
+namespace Microsoft.AspNetCore.Blazor.Browser.Services
 {
-    // TODO: Make this not static, and wrap it in an interface that can be injected through DI.
-
     /// <summary>
-    /// Helpers for working with URIs and navigation state.
+    /// Default browser implementation of <see cref="IUriHelper"/>.
     /// </summary>
-    public static class UriHelper
+    public class BrowserUriHelper : IUriHelper
     {
-        static readonly string _functionPrefix = typeof(UriHelper).FullName;
+        // Since there's only one browser (and hence only one navigation state), the internal state
+        // is all static. In typical usage the DI system will register BrowserUriHelper as a singleton
+        // so it makes no difference, but if you manually instantiate more than one BrowserUriHelper
+        // that's fine too - they will just share their internal state.
+        // This class will never be used during server-side prerendering, so we don't have thread-
+        // safety concerns due to the static state.
+        static readonly string _functionPrefix = typeof(BrowserUriHelper).FullName;
+        static bool _hasEnabledNavigationInterception;
         static string _currentAbsoluteUri;
+        static EventHandler<string> _onLocationChanged;
         static string _baseUriString;
         static Uri _baseUri;
-        static EventHandler<string> _onLocationChanged;
-        static bool _hasEnabledNavigationInterception;
 
-        /// <summary>
+        /// <inheritdoc />
-        /// An event that fires when the navigation location has changed.
+        public event EventHandler<string> OnLocationChanged
-        /// </summary>
-        public static event EventHandler<string> OnLocationChanged
         {
             add
             {
@@ -38,63 +41,34 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
             }
         }
 
-        /// <summary>
+        /// <inheritdoc />
-        /// Gets the URI prefix that can be prepended before URI paths to produce an absolute URI.
+        public string GetBaseUriPrefix()
-        /// Typically this corresponds to the 'href' attribute on the document's &lt;base&gt; element.
-        /// </summary>
-        /// <returns>The URI prefix.</returns>
-        public static string GetBaseUriPrefix()
         {
             EnsureBaseUriPopulated();
             return _baseUriString;
         }
 
-        private static void EnsureBaseUriPopulated()
+        /// <inheritdoc />
-        {
+        public string GetAbsoluteUri()
-            // The <base href> is fixed for the lifetime of the page, so just cache it
-            if (_baseUriString == null)
-            {
-                var baseUri = RegisteredFunction.InvokeUnmarshalled<string>(
-                    $"{_functionPrefix}.getBaseURI");
-                _baseUriString = ToBaseUriPrefix(baseUri);
-                _baseUri = new Uri(_baseUriString);
-            }
-        }
-
-        /// <summary>
-        /// Gets the browser's current absolute URI.
-        /// </summary>
-        /// <returns>The browser's current absolute URI.</returns>
-        public static string GetAbsoluteUri()
         {
             if (_currentAbsoluteUri == null)
             {
                 _currentAbsoluteUri = RegisteredFunction.InvokeUnmarshalled<string>(
-                $"{_functionPrefix}.getLocationHref");
+                    $"{_functionPrefix}.getLocationHref");
             }
 
             return _currentAbsoluteUri;
         }
 
-        /// <summary>
+        /// <inheritdoc />
-        /// Converts a relative URI into an absolute one.
+        public Uri ToAbsoluteUri(string relativeUri)
-        /// </summary>
-        /// <param name="relativeUri">The relative URI.</param>
-        /// <returns>The absolute URI.</returns>
-        public static Uri ToAbsoluteUri(string relativeUri)
         {
             EnsureBaseUriPopulated();
             return new Uri(_baseUri, relativeUri);
         }
 
-        /// <summary>
+        /// <inheritdoc />
-        /// Given a base URI prefix (e.g., one previously returned by <see cref="GetBaseUriPrefix"/>),
+        public string ToBaseRelativePath(string baseUriPrefix, string absoluteUri)
-        /// converts an absolute URI into one relative to the base URI prefix.
-        /// </summary>
-        /// <param name="baseUriPrefix">The base URI prefix (e.g., previously returned by <see cref="GetBaseUriPrefix"/>).</param>
-        /// <param name="absoluteUri">An absolute URI that is within the space of the base URI prefix.</param>
-        /// <returns>A relative URI path.</returns>
-        public static string ToBaseRelativePath(string baseUriPrefix, string absoluteUri)
         {
             if (absoluteUri.Equals(baseUriPrefix, StringComparison.Ordinal))
             {
@@ -117,6 +91,18 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Routing
             throw new ArgumentException($"The URI '{absoluteUri}' is not contained by the base URI '{baseUriPrefix}'.");
         }
 
+        private static void EnsureBaseUriPopulated()
+        {
+            // The <base href> is fixed for the lifetime of the page, so just cache it
+            if (_baseUriString == null)
+            {
+                var baseUri = RegisteredFunction.InvokeUnmarshalled<string>(
+                    $"{_functionPrefix}.getBaseURI");
+                _baseUriString = ToBaseUriPrefix(baseUri);
+                _baseUri = new Uri(_baseUriString);
+            }
+        }
+
         private static void NotifyLocationChanged(string newAbsoluteUri)
         {
             _currentAbsoluteUri = newAbsoluteUri;

src/Microsoft.AspNetCore.Blazor.Browser/Services/DefaultBrowserServiceProvider.cs

@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using Microsoft.AspNetCore.Blazor.Services;
 using Microsoft.Extensions.DependencyInjection;
 using System;
 
@@ -39,7 +40,7 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Services
 
         private void AddDefaultServices(ServiceCollection serviceCollection)
         {
-            // TODO: Add default services for HttpClient, IUrlHelper, etc.
+            serviceCollection.AddSingleton<IUriHelper>(new BrowserUriHelper());
         }
     }
 }

src/Microsoft.AspNetCore.Blazor/Services/IUriHelper.cs

@@ -0,0 +1,48 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.AspNetCore.Blazor.Services
+{
+    /// <summary>
+    /// Helpers for working with URIs and navigation state.
+    /// </summary>
+    public interface IUriHelper
+    {
+        /// <summary>
+        /// Gets the current absolute URI.
+        /// </summary>
+        /// <returns>The browser's current absolute URI.</returns>
+        string GetAbsoluteUri();
+
+        /// <summary>
+        /// An event that fires when the navigation location has changed.
+        /// </summary>
+        event EventHandler<string> OnLocationChanged;
+
+        /// <summary>
+        /// Converts a relative URI into an absolute one (by resolving it
+        /// relative to the current absolute URI).
+        /// </summary>
+        /// <param name="relativeUri">The relative URI.</param>
+        /// <returns>The absolute URI.</returns>
+        Uri ToAbsoluteUri(string href);
+
+        /// <summary>
+        /// Gets the URI prefix that can be prepended before URI paths to produce an absolute URI.
+        /// Typically this corresponds to the 'href' attribute on the document's &lt;base&gt; element.
+        /// </summary>
+        /// <returns>The URI prefix.</returns>
+        string GetBaseUriPrefix();
+
+        /// <summary>
+        /// Given a base URI prefix (e.g., one previously returned by <see cref="GetBaseUriPrefix"/>),
+        /// converts an absolute URI into one relative to the base URI prefix.
+        /// </summary>
+        /// <param name="baseUriPrefix">The base URI prefix (e.g., previously returned by <see cref="GetBaseUriPrefix"/>).</param>
+        /// <param name="absoluteUri">An absolute URI that is within the space of the base URI prefix.</param>
+        /// <returns>A relative URI path.</returns>
+        string ToBaseRelativePath(string baseUriPrefix, string locationAbsolute);
+    }
+}

test/Microsoft.AspNetCore.Blazor.Browser.Test/BrowserUriHelperTest.cs

@@ -1,14 +1,16 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using Microsoft.AspNetCore.Blazor.Browser.Routing;
+using Microsoft.AspNetCore.Blazor.Browser.Services;
 using System;
 using Xunit;
 
 namespace Microsoft.AspNetCore.Blazor.Browser.Test
 {
-    public class UriHelperTest
+    public class BrowserUriHelperTest
     {
+        private BrowserUriHelper _browserUriHelper = new BrowserUriHelper();
+
         [Theory]
         [InlineData("scheme://host/", "scheme://host")]
         [InlineData("scheme://host:123/", "scheme://host:123")]
@@ -17,7 +19,7 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Test
         [InlineData("scheme://host/path/page?query=string&another=here", "scheme://host/path")]
         public void ComputesCorrectBaseUriPrefix(string baseUri, string expectedResult)
         {
-            var actualResult = UriHelper.ToBaseUriPrefix(baseUri);
+            var actualResult = BrowserUriHelper.ToBaseUriPrefix(baseUri);
             Assert.Equal(expectedResult, actualResult);
         }
 
@@ -29,7 +31,7 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Test
         [InlineData("scheme://host/path", "scheme://host/path", "/")]
         public void ComputesCorrectValidBaseRelativePaths(string baseUriPrefix, string absoluteUri, string expectedResult)
         {
-            var actualResult = UriHelper.ToBaseRelativePath(baseUriPrefix, absoluteUri);
+            var actualResult = _browserUriHelper.ToBaseRelativePath(baseUriPrefix, absoluteUri);
             Assert.Equal(expectedResult, actualResult);
         }
 
@@ -40,7 +42,7 @@ namespace Microsoft.AspNetCore.Blazor.Browser.Test
         {
             var ex = Assert.Throws<ArgumentException>(() =>
             {
-                UriHelper.ToBaseRelativePath(baseUriPrefix, absoluteUri);
+                _browserUriHelper.ToBaseRelativePath(baseUriPrefix, absoluteUri);
             });
 
             Assert.Equal(