Refactor MVC View Engine (#375)

Fixes #361

Fluid.MvcSample/Startup.cs

@@ -1,6 +1,4 @@
-using Fluid.MvcSample.Models;
-using Fluid.MvcViewEngine;
-using Fluid.ViewEngine;
+using Fluid.MvcViewEngine;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
@@ -14,7 +12,7 @@ public class Startup
         // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
         public void ConfigureServices(IServiceCollection services)
         {
-            services.Configure<FluidViewEngineOptions>(options =>
+            services.Configure<FluidMvcViewOptions>(options =>
             {
                 options.Parser = new CustomFluidViewParser();
                 options.TemplateOptions.MemberAccessStrategy = UnsafeMemberAccessStrategy.Instance;

Fluid.MvcViewEngine/FluidMvcViewOptions.cs

@@ -0,0 +1,23 @@
+using Fluid.ViewEngine;
+using System.Collections.Generic;
+
+namespace Fluid.MvcViewEngine
+{
+    public class FluidMvcViewOptions : FluidViewEngineOptions
+    {
+        /// <summary>
+        /// Gets les list of view location formats.
+        /// </summary>
+        /// <remarks>
+        /// The first argument '{0}' is the view name.
+        /// The second argument '{1}' is the controller name.
+        /// The third argument '{2}' is the area name.
+        /// </remarks>
+        /// <example>
+        /// "Views/{1}/{0}"
+        /// "Views/Shared/{0}"
+        /// </example>
+        public IList<string> ViewLocationFormats { get; } = new List<string>();
+
+    }
+}

Fluid.MvcViewEngine/FluidRendering.cs

@@ -1,152 +1,47 @@
-using Fluid.Ast;
-using Fluid.Parser;
-using Fluid.ViewEngine;
+using Fluid.ViewEngine;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
-using Microsoft.Extensions.Caching.Memory;
-using Microsoft.Extensions.FileProviders;
 using Microsoft.Extensions.Options;
-using System;
-using System.Collections.Generic;
 using System.IO;
 using System.Threading.Tasks;
 
 namespace Fluid.MvcViewEngine
 {
     /// <summary>
-    /// This class is registered as a singleton. As such it can store application wide 
-    /// state.
+    /// This class is registered as a singleton.
     /// </summary>
-    public class FluidRendering : IFluidRendering
+    public class FluidRendering
     {
-        static FluidRendering()
-        {
-        }
+        private readonly FluidViewRenderer _fluidViewRenderer;
 
         public FluidRendering(
-            IMemoryCache memoryCache,
-            IOptions<FluidViewEngineOptions> optionsAccessor,
+            IOptions<FluidMvcViewOptions> optionsAccessor,
             IWebHostEnvironment hostingEnvironment)
         {
-            _memoryCache = memoryCache;
             _hostingEnvironment = hostingEnvironment;
             _options = optionsAccessor.Value;
 
             _options.TemplateOptions.MemberAccessStrategy.Register<ViewDataDictionary>();
             _options.TemplateOptions.MemberAccessStrategy.Register<ModelStateDictionary>();
-            _options.TemplateOptions.FileProvider = new FileProviderMapper(_options.IncludesFileProvider ?? _hostingEnvironment.ContentRootFileProvider, "Views");
+            _options.TemplateOptions.FileProvider = new FileProviderMapper(_options.IncludesFileProvider ?? _hostingEnvironment.ContentRootFileProvider, _options.ViewsPath);
+
+            _fluidViewRenderer = new FluidViewRenderer(_options);
+
+            _options.ViewsFileProvider ??= _hostingEnvironment.ContentRootFileProvider;
         }
 
-        private readonly IMemoryCache _memoryCache;
         private readonly IWebHostEnvironment _hostingEnvironment;
         private readonly FluidViewEngineOptions _options;
 
-        public async ValueTask<string> RenderAsync(string path, object model, ViewDataDictionary viewData, ModelStateDictionary modelState)
+        public async Task RenderAsync(TextWriter writer, string path, object model, ViewDataDictionary viewData, ModelStateDictionary modelState)
         {
             var context = new TemplateContext(_options.TemplateOptions);
             context.SetValue("ViewData", viewData);
             context.SetValue("ModelState", modelState);
             context.SetValue("Model", model);
 
-            // Provide some services to all statements
-            context.AmbientValues[Constants.ViewPathIndex] = path;
-            context.AmbientValues[Constants.SectionsIndex] = new Dictionary<string, IReadOnlyList<Statement>>();
-
-            var template = ParseLiquidFile(path, _options.ViewsFileProvider ?? _hostingEnvironment.ContentRootFileProvider, true);
-
-            var body = await template.RenderAsync(context, _options.TextEncoder);
-
-            // If a layout is specified while rendering a view, execute it
-            if (context.AmbientValues.TryGetValue(Constants.LayoutIndex, out var layoutPath))
-            {
-                context.AmbientValues[Constants.ViewPathIndex] = layoutPath;
-                context.AmbientValues[Constants.BodyIndex] = body;
-                var layoutTemplate = ParseLiquidFile((string)layoutPath, _options.ViewsFileProvider ?? _hostingEnvironment.ContentRootFileProvider, false);
-
-                return await layoutTemplate.RenderAsync(context, _options.TextEncoder);
-            }
-
-            return body;
-        }
-
-        public List<string> FindViewStarts(string viewPath, IFileProvider fileProvider)
-        {
-            var viewStarts = new List<string>();
-            int index = viewPath.Length - 1;
-            while (!String.IsNullOrEmpty(viewPath) &&
-                !(String.Equals(viewPath, "Views", StringComparison.OrdinalIgnoreCase)))
-            {
-                index = viewPath.LastIndexOf('/', index);
-
-                if (index == -1)
-                {
-                    return viewStarts;
-                }
-
-                viewPath = viewPath.Substring(0, index + 1) + Constants.ViewStartFilename;
-
-                var viewStartInfo = fileProvider.GetFileInfo(viewPath);
-                if (viewStartInfo.Exists)
-                {
-                    viewStarts.Add(viewPath);
-                }
-
-                index = index - 1;
-            }
-
-            return viewStarts;
-        }
-
-        public IFluidTemplate ParseLiquidFile(string path, IFileProvider fileProvider, bool includeViewStarts)
-        {
-            return _memoryCache.GetOrCreate(path, viewEntry =>
-            {
-                var subTemplates = new List<IFluidTemplate>();
-
-                // Default sliding expiration to prevent the entries for being kept indefinitely
-                viewEntry.SlidingExpiration = TimeSpan.FromHours(1);
-
-                var fileInfo = fileProvider.GetFileInfo(path);
-                viewEntry.ExpirationTokens.Add(fileProvider.Watch(path));
-
-                if (includeViewStarts)
-                {
-                    // Add ViewStart files
-                    foreach (var viewStartPath in FindViewStarts(path, fileProvider))
-                    {
-                        // Redefine the current view path while processing ViewStart files
-                        var callbackTemplate = new FluidTemplate(new CallbackStatement((writer, encoder, context) =>
-                        {
-                            context.AmbientValues[Constants.ViewPathIndex] = viewStartPath;
-                            return new ValueTask<Completion>(Completion.Normal);
-                        }));
-
-                        var viewStartTemplate = ParseLiquidFile(viewStartPath, fileProvider, false);
-
-                        subTemplates.Add(callbackTemplate);
-                        subTemplates.Add(viewStartTemplate);
-                    }
-                }
-
-                using (var stream = fileInfo.CreateReadStream())
-                {
-                    using (var sr = new StreamReader(stream))
-                    {
-                        var fileContent = sr.ReadToEnd();
-                        if (_options.Parser.TryParse(fileContent, out var template, out var errors))
-                        {
-                            subTemplates.Add(template);
-
-                            return new CompositeFluidTemplate(subTemplates);
-                        }
-                        else
-                        {
-                            throw new ParseException(errors);
-                        }
-                    }
-                }
-            });
+            await _fluidViewRenderer.RenderViewAsync(writer, path, context);
         }
     }
 }

Fluid.MvcViewEngine/FluidTagHelper.cs

@@ -1,14 +1,15 @@
-using System.Threading.Tasks;
+using System.IO;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Razor.TagHelpers;
 
 namespace Fluid.MvcViewEngine
 {
     [HtmlTargetElement("fluid")]
     public class FluidTagHelper : TagHelper
     {
-        public IFluidRendering _fluidRendering { get; set; }
+        private FluidRendering _fluidRendering { get; set; }
 
-        public FluidTagHelper(IFluidRendering fluidRendering)
+        public FluidTagHelper(FluidRendering fluidRendering)
         {
             _fluidRendering = fluidRendering;
         }
@@ -21,21 +22,26 @@ public FluidTagHelper(IFluidRendering fluidRendering)
 
         public override Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
         {
-            static async Task Awaited(TagHelperOutput o, ValueTask<string> t)
+            static async Task Awaited(TagHelperOutput o, StringWriter sw, Task t)
             {
+                await t;
                 o.TagName = null;
-                o.Content.AppendHtml(await t);
+                o.Content.AppendHtml(sw.ToString());
             }
 
-            var task = _fluidRendering.RenderAsync(View, Model, null, null);
-            if (task.IsCompletedSuccessfully)
+            using (var sw = new StringWriter())
             {
-                output.TagName = null;
-                output.Content.AppendHtml(task.Result);
-                return Task.FromResult(output);
-            }
+                var task = _fluidRendering.RenderAsync(sw, View, Model, null, null);
+
+                if (task.IsCompletedSuccessfully)
+                {
+                    output.TagName = null;
+                    output.Content.AppendHtml(sw.ToString());
+                    return Task.FromResult(output);
+                }
 
-            return Awaited(output, task);
+                return Awaited(output, sw, task);
+            }
         }
     }
 }

Fluid.MvcViewEngine/FluidView.cs

@@ -7,9 +7,9 @@ namespace Fluid.MvcViewEngine
     public class FluidView : IView
     {
         private string _path;
-        private IFluidRendering _fluidRendering;
+        private FluidRendering _fluidRendering;
 
-        public FluidView(string path, IFluidRendering fluidRendering)
+        public FluidView(string path, FluidRendering fluidRendering)
         {
             _path = path;
             _fluidRendering = fluidRendering;
@@ -25,8 +25,7 @@ public string Path
 
         public async Task RenderAsync(ViewContext context)
         {
-            var result = await _fluidRendering.RenderAsync(Path, context.ViewData.Model, context.ViewData, context.ModelState);
-            context.Writer.Write(result);
+            await _fluidRendering.RenderAsync(context.Writer, Path, context.ViewData.Model, context.ViewData, context.ModelState);
         }
     }
 }

Fluid.MvcViewEngine/FluidViewEngine.cs

@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using Fluid.ViewEngine;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.ViewEngines;
@@ -12,15 +11,15 @@ namespace Fluid.MvcViewEngine
 {
     public class FluidViewEngine : IFluidViewEngine
     {
-        private IFluidRendering _fluidRendering;
+        private FluidRendering _fluidRendering;
         private readonly IWebHostEnvironment _hostingEnvironment;
         public static readonly string ViewExtension = ".liquid";
         private const string ControllerKey = "controller";
         private const string AreaKey = "area";
-        private FluidViewEngineOptions _options;
+        private FluidMvcViewOptions _options;
 
-        public FluidViewEngine(IFluidRendering fluidRendering,
-            IOptions<FluidViewEngineOptions> optionsAccessor,
+        public FluidViewEngine(FluidRendering fluidRendering,
+            IOptions<FluidMvcViewOptions> optionsAccessor,
             IWebHostEnvironment hostingEnvironment)
         {
             _options = optionsAccessor.Value;
@@ -30,27 +29,30 @@ public FluidViewEngine(IFluidRendering fluidRendering,
 
         public ViewEngineResult FindView(ActionContext context, string viewName, bool isMainPage)
         {
-            return LocatePageFromViewLocations(context, viewName, isMainPage);
+            return LocatePageFromViewLocations(context, viewName);
         }
 
-        private ViewEngineResult LocatePageFromViewLocations(
-            ActionContext actionContext,
-            string viewName,
-            bool isMainPage)
+        private ViewEngineResult LocatePageFromViewLocations(ActionContext actionContext, string viewName)
         {
             var controllerName = GetNormalizedRouteValue(actionContext, ControllerKey);
             var areaName = GetNormalizedRouteValue(actionContext, AreaKey);
 
             var fileProvider = _options.ViewsFileProvider ?? _hostingEnvironment.ContentRootFileProvider;
 
             var checkedLocations = new List<string>();
+
             foreach (var location in _options.ViewLocationFormats)
             {
-                var view = string.Format(location, viewName, controllerName);
-                if(fileProvider.GetFileInfo(view).Exists)
+                var view = string.Format(location, viewName, controllerName, areaName);
+
+                if (fileProvider.GetFileInfo(view).Exists)
+                {
                     return ViewEngineResult.Found("Default", new FluidView(view, _fluidRendering));
+                }
+
                 checkedLocations.Add(view);
             }
+
             return ViewEngineResult.NotFound(viewName, checkedLocations);
         }
 

Fluid.MvcViewEngine/FluidViewEngineOptionsSetup.cs

@@ -1,10 +1,12 @@
-using Fluid.ViewEngine;
-using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Options;
 
 namespace Fluid.MvcViewEngine
 {
-    public class FluidViewEngineOptionsSetup : ConfigureOptions<FluidViewEngineOptions>
+    /// <summary>
+    /// Defines the default configuration of <see cref="FluidMvcViewOptions"/>.
+    /// </summary>
+    internal class FluidViewEngineOptionsSetup : ConfigureOptions<FluidMvcViewOptions>
     {
         public FluidViewEngineOptionsSetup(IWebHostEnvironment webHostEnvironment)
             : base(options =>

Fluid.MvcViewEngine/MvcViewFeaturesMvcBuilderExtensions.cs

@@ -16,15 +16,15 @@ public static IMvcBuilder AddFluid(this IMvcBuilder builder, Action<FluidViewEng
             }
 
             builder.Services.AddOptions();
-            builder.Services.AddTransient<IConfigureOptions<FluidViewEngineOptions>, FluidViewEngineOptionsSetup>();
+            builder.Services.AddTransient<IConfigureOptions<FluidMvcViewOptions>, FluidViewEngineOptionsSetup>();
 
             if (setupAction != null)
             {
                 builder.Services.Configure(setupAction);
             }
 
-            builder.Services.AddTransient<IConfigureOptions<MvcViewOptions>, FluidMvcViewOptionsSetup>();
-            builder.Services.AddSingleton<IFluidRendering, FluidRendering>();
+            builder.Services.AddTransient<IConfigureOptions<MvcViewOptions>, MvcViewOptionsSetup>();
+            builder.Services.AddSingleton<FluidRendering>();
             builder.Services.AddSingleton<IFluidViewEngine, FluidViewEngine>();
             return builder;