Fix file change detection (#401)

Fixes #400
sebastienros · Nov 22, 2021 · ff64afa · ff64afa
1 parent 1c94467
commit ff64afa
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Showing 14 changed files with 119 additions and 176 deletions.
diff --git a/Fluid.MinimalApisSample/README.md b/Fluid.MinimalApisSample/README.md
diff --git a/Fluid.MinimalApisSample/Views/_layout.liquid b/Fluid.MinimalApisSample/Views/_layout.liquid
@@ -1,33 +1,19 @@
 <!doctype html>
 <html lang="en">
   <head>
-    <!-- Required meta tags -->
     <meta charset="utf-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1">
-
-    <!-- Bootstrap CSS -->
-    <link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-eOJMYsd53ii+scO/bJGFsiCZc+5NDVN2yr8+0RDqr0Ql0h+rP48ckxlpbzKgwra6" crossorigin="anonymous">
-
     <title>Hello, world!</title>
   </head>
   <body>
 
-  <div class="px-4 py-5 my-5 text-center">
-    <h1 class="display-5 fw-bold">Title from the layout</h1>
-  <div class="col-lg-6 mx-auto">
-    <p class="lead mb-4">
-		{% renderbody %}
-
-		{% partial 'Component', x: 1, y:2 %}
+    <h1>Title from the layout</h1>
+    {% renderbody %}
 
-	</p>
-  </div>
-</div>
+    {% partial 'Component', x: 1, y:2 %}
 
-	<pre>
-	{% rendersection footer %}
-	</pre>
+    <footer>
+      {% rendersection footer %}
+    </footer>
 
-    <script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-JEW9xMcG8R+pH31jmWH6WWP0WintQrMb4s7ZOdauHnUtxwoG2vI5DkLtS3qm9Ekf" crossorigin="anonymous"></script>
   </body>
-</html>
+</html>
diff --git a/Fluid.MinimalApisSample/Views/_viewstart.liquid b/Fluid.MinimalApisSample/Views/_viewstart.liquid
@@ -1,2 +1 @@
 {% layout '_Layout' %}
-From /Views/_ViewStart.liquid
diff --git a/Fluid.MinimalApisSample/Views/component.liquid b/Fluid.MinimalApisSample/Views/component.liquid
@@ -1 +1 @@
-<div>Using a component {{ x }} + {{ y }} = {{ x | plus: y }}</div>
+<div>Using a component {{ x }} + {{ y }} = {{ x | plus: y }}</div>
diff --git a/Fluid.MinimalApisSample/Views/index.liquid b/Fluid.MinimalApisSample/Views/index.liquid
@@ -1,10 +1,12 @@
 <hr />
 Hello World from the body
 
+<hr />
 Name: {{ Name }} <br />
 IsComplete: {{ IsComplete}}
+
 <hr />
 
 {% section footer %}
 Hello from the footer section
-{% endsection %}
+{% endsection %}
diff --git a/Fluid.MvcViewEngine/Fluid.MvcViewEngine.csproj b/Fluid.MvcViewEngine/Fluid.MvcViewEngine.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
-    <LangVersion>9</LangVersion>
+    <LangVersion>latest</LangVersion>
     <PackageIcon>logo_64x64.png</PackageIcon>
     <IsPackable>true</IsPackable>
   </PropertyGroup>

diff --git a/Fluid.MvcViewEngine/FluidViewEngine.cs b/Fluid.MvcViewEngine/FluidViewEngine.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
@@ -17,6 +18,7 @@ public class FluidViewEngine : IFluidViewEngine
         private const string ControllerKey = "controller";
         private const string AreaKey = "area";
         private FluidMvcViewOptions _options;
+        private ConcurrentDictionary<LocationCacheKey, FluidView> _locationCache = new();
 
         public FluidViewEngine(FluidRendering fluidRendering,
             IOptions<FluidMvcViewOptions> optionsAccessor,
@@ -37,19 +39,28 @@ private ViewEngineResult LocatePageFromViewLocations(ActionContext actionContext
             var controllerName = GetNormalizedRouteValue(actionContext, ControllerKey);
             var areaName = GetNormalizedRouteValue(actionContext, AreaKey);
 
+            var key = new LocationCacheKey(controllerName, areaName, viewName);
+
+            if (_locationCache.TryGetValue(key, out var fluidView))
+            {
+                return ViewEngineResult.Found(viewName, fluidView);
+            }
+
             var fileProvider = _options.ViewsFileProvider ?? _hostingEnvironment.ContentRootFileProvider;
 
-            var checkedLocations = new List<string>();
+            List<string> checkedLocations = null;
 
             foreach (var location in _options.ViewsLocationFormats)
             {
                 var view = String.Format(location, viewName, controllerName, areaName);
 
                 if (fileProvider.GetFileInfo(view).Exists)
                 {
-                    return ViewEngineResult.Found(viewName, new FluidView(view, _fluidRendering));
+                    _locationCache[key] = fluidView = new FluidView(view, _fluidRendering);
+                    return ViewEngineResult.Found(viewName, fluidView);
                 }
 
+                checkedLocations ??= new();
                 checkedLocations.Add(view);
             }
 
@@ -139,8 +150,7 @@ public static string GetNormalizedRouteValue(ActionContext context, string key)
             var actionDescriptor = context.ActionDescriptor;
             string normalizedValue = null;
 
-            if (actionDescriptor.RouteValues.TryGetValue(key, out string value) &&
-                !string.IsNullOrEmpty(value))
+            if (actionDescriptor.RouteValues.TryGetValue(key, out string value) && !string.IsNullOrEmpty(value))
             {
                 normalizedValue = value;
             }
@@ -153,5 +163,7 @@ public static string GetNormalizedRouteValue(ActionContext context, string key)
 
             return stringRouteValue;
         }
+
+        public readonly record struct LocationCacheKey(string ControllerName, string AreaName, string ViewName);
     }
 }
diff --git a/Fluid.MvcViewEngine/IsExternalInit.cs b/Fluid.MvcViewEngine/IsExternalInit.cs
@@ -0,0 +1,10 @@
+#if NETCOREAPP3_1
+using System.ComponentModel;
+
+// Fix for: error CS0518: Predefined type 'System.Runtime.CompilerServices.IsExternalInit' is not defined or imported
+namespace System.Runtime.CompilerServices
+{
+    [EditorBrowsable(EditorBrowsableState.Never)]
+    internal class IsExternalInit { }
+}
+#endif
diff --git a/Fluid.Tests/Mocks/MockFileProvider.cs b/Fluid.Tests/Mocks/MockFileProvider.cs
@@ -3,6 +3,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Threading.Tasks;
 
 namespace Fluid.Tests.Mocks
 {
@@ -45,7 +46,7 @@ public MockFileProvider Add(string path, string content)
 
         public IChangeToken Watch(string filter)
         {
-            throw new NotImplementedException();
+            return NullChangeToken.Singleton;
         }
 
         private string NormalizePath(string path)

diff --git a/Fluid.ViewEngine/Fluid.ViewEngine.csproj b/Fluid.ViewEngine/Fluid.ViewEngine.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>netstandard2.0;netstandard2.1;netcoreapp3.1;net5.0;net6.0</TargetFrameworks>
-    <LangVersion>9</LangVersion>
+    <LangVersion>latest</LangVersion>
     <IsPackable>true</IsPackable>
     <PackageIcon>logo_64x64.png</PackageIcon>
   </PropertyGroup>

diff --git a/Fluid.ViewEngine/FluidViewEngineOptions.cs b/Fluid.ViewEngine/FluidViewEngineOptions.cs
@@ -49,5 +49,10 @@ public class FluidViewEngineOptions
         /// /Views/Includes/{0}.liquid
         /// </example>
         public List<string> PartialsLocationFormats { get; } = new();
+
+        /// <summary>
+        /// Gets or sets whether files should be reloaded automatically when changed. Default is <code>true</code>;
+        /// </summary>
+        public bool TrackFileChanges { get; set; } = true;
     }
 }
diff --git a/Fluid.ViewEngine/FluidViewRenderer.cs b/Fluid.ViewEngine/FluidViewRenderer.cs
@@ -14,7 +14,13 @@ namespace Fluid.ViewEngine
     /// </summary>
     public class FluidViewRenderer : IFluidViewRenderer
     {
-        private readonly ConcurrentDictionary<string, IFluidTemplate> _cache = new ConcurrentDictionary<string, IFluidTemplate>();
+        private class CacheEntry
+        {
+            public IDisposable Callback;
+            public ConcurrentDictionary<string, IFluidTemplate> TemplateCache = new();
+        }
+
+        private readonly ConcurrentDictionary<IFileProvider, CacheEntry> _cache = new();
 
         public FluidViewRenderer(FluidViewEngineOptions fluidViewEngineOptions)
         {
@@ -34,18 +40,18 @@ public virtual async Task RenderViewAsync(TextWriter writer, string relativePath
 
             var template = await GetFluidTemplateAsync(relativePath, _fluidViewEngineOptions.ViewsFileProvider, true);
 
-            // The body is rendered and buffer before the Layout since it can contain fragments 
+            // The body is rendered and buffered before the Layout since it can contain fragments 
             // that need to be rendered as part of the Layout.
             // Also the body or its _ViewStarts might contain a Layout tag.
 
             var body = await template.RenderAsync(context, _fluidViewEngineOptions.TextEncoder);
 
             // If a layout is specified while rendering a view, execute it
-            if (context.AmbientValues.TryGetValue(Constants.LayoutIndex, out var layoutPath) && !String.IsNullOrEmpty(Convert.ToString(layoutPath)))
+            if (context.AmbientValues.TryGetValue(Constants.LayoutIndex, out var layoutPath) && layoutPath is string layoutPathString && !String.IsNullOrEmpty(layoutPathString))
             {
                 context.AmbientValues[Constants.ViewPathIndex] = layoutPath;
                 context.AmbientValues[Constants.BodyIndex] = body;
-                var layoutTemplate = await GetFluidTemplateAsync((string)layoutPath, _fluidViewEngineOptions.ViewsFileProvider, false);
+                var layoutTemplate = await GetFluidTemplateAsync(layoutPathString, _fluidViewEngineOptions.ViewsFileProvider, false);
 
                 await layoutTemplate.RenderAsync(writer, _fluidViewEngineOptions.TextEncoder, context);
             }
@@ -58,7 +64,6 @@ public virtual async Task RenderViewAsync(TextWriter writer, string relativePath
         public virtual async Task RenderPartialAsync(TextWriter writer, string relativePath, TemplateContext context)
         {
             // Substitute View Path
-            context.AmbientValues.TryGetValue(Constants.ViewPathIndex, out var viewPath);
             context.AmbientValues[Constants.ViewPathIndex] = relativePath;
 
             var template = await GetFluidTemplateAsync(relativePath, _fluidViewEngineOptions.PartialsFileProvider, false);
@@ -97,30 +102,49 @@ protected virtual List<string> FindViewStarts(string viewPath, IFileProvider fil
             return viewStarts;
         }
 
-        protected async ValueTask<IFluidTemplate> GetFluidTemplateAsync(string path, IFileProvider fileProvider, bool includeViewStarts)
+        protected virtual async ValueTask<IFluidTemplate> GetFluidTemplateAsync(string path, IFileProvider fileProvider, bool includeViewStarts)
         {
-            if (TryGetCachedTemplate(path, out var template))
+            var cache = _cache.GetOrAdd(fileProvider, f =>
+            {
+                var cacheEntry = new CacheEntry();
+
+                if (_fluidViewEngineOptions.TrackFileChanges)
+                {
+                    Action<object> callback = null;
+
+                    callback = c =>
+                    {
+                        // The order here is important. We need to take the token and then apply our changes BEFORE
+                        // registering. This prevents us from possible having two change updates to process concurrently.
+                        //
+                        // If the file changes after we take the token, then we'll process the update immediately upon
+                        // registering the callback.
+
+                        var entry = (CacheEntry)c;
+                        var previousCallBack = entry.Callback;
+                        previousCallBack?.Dispose();
+                        var token = fileProvider.Watch("**/*" + Constants.ViewExtension);
+                        entry.TemplateCache.Clear();
+                        entry.Callback = token.RegisterChangeCallback(callback, c);
+                    };
+
+                    cacheEntry.Callback = fileProvider.Watch("**/*" + Constants.ViewExtension).RegisterChangeCallback(callback, cacheEntry);
+                }
+                return cacheEntry;
+            });
+
+            if (cache.TemplateCache.TryGetValue(path, out var template))
             {
                 return template;
             }
 
             template = await ParseLiquidFileAsync(path, fileProvider, includeViewStarts);
 
-            SetCachedTemplate(path, template);
+            cache.TemplateCache[path] = template;
 
             return template;
         }
 
-        protected virtual bool TryGetCachedTemplate(string path, out IFluidTemplate template)
-        {
-            return _cache.TryGetValue(path, out template);
-        }
-
-        protected virtual void SetCachedTemplate(string path, IFluidTemplate template)
-        {
-            _cache[path] = template;
-        }
-
         protected virtual async ValueTask<IFluidTemplate> ParseLiquidFileAsync(string path, IFileProvider fileProvider, bool includeViewStarts)
         {
             var fileInfo = fileProvider.GetFileInfo(path);
Original file line number	Diff line number	Diff line change
		@@ -1,2 +1 @@
		{% layout '_Layout' %}
		From /Views/_ViewStart.liquid
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		<div>Using a component {{ x }} + {{ y }} = {{ x \| plus: y }}</div>
		<div>Using a component {{ x }} + {{ y }} = {{ x \| plus: y }}</div>