aspnetcore/src/Microsoft.AspNet.Mvc.Razor/RazorViewEngine.cs

539 lines
21 KiB
C#

// 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;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Text.Encodings.Web;
using Microsoft.AspNet.Mvc.Logging;
using Microsoft.AspNet.Mvc.Routing;
using Microsoft.AspNet.Mvc.ViewEngines;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Primitives;
namespace Microsoft.AspNet.Mvc.Razor
{
/// <summary>
/// Default implementation of <see cref="IRazorViewEngine"/>.
/// </summary>
/// <remarks>
/// For <c>ViewResults</c> returned from controllers, views should be located in <see cref="ViewLocationFormats"/>
/// by default. For the controllers in an area, views should exist in <see cref="AreaViewLocationFormats"/>.
/// </remarks>
public class RazorViewEngine : IRazorViewEngine
{
private const string ViewExtension = ".cshtml";
private const string ControllerKey = "controller";
private const string AreaKey = "area";
private static readonly ViewLocationCacheItem[] EmptyViewStartLocationCacheItems =
new ViewLocationCacheItem[0];
private static readonly TimeSpan _cacheExpirationDuration = TimeSpan.FromMinutes(20);
private readonly IRazorPageFactoryProvider _pageFactory;
private readonly IList<IViewLocationExpander> _viewLocationExpanders;
private readonly IRazorPageActivator _pageActivator;
private readonly HtmlEncoder _htmlEncoder;
private readonly ILogger _logger;
/// <summary>
/// Initializes a new instance of the <see cref="RazorViewEngine" />.
/// </summary>
public RazorViewEngine(
IRazorPageFactoryProvider pageFactory,
IRazorPageActivator pageActivator,
HtmlEncoder htmlEncoder,
IOptions<RazorViewEngineOptions> optionsAccessor,
ILoggerFactory loggerFactory)
{
_pageFactory = pageFactory;
_pageActivator = pageActivator;
_viewLocationExpanders = optionsAccessor.Value.ViewLocationExpanders;
_htmlEncoder = htmlEncoder;
_logger = loggerFactory.CreateLogger<RazorViewEngine>();
ViewLookupCache = new MemoryCache(new MemoryCacheOptions
{
CompactOnMemoryPressure = false
});
}
/// <summary>
/// Gets the locations where this instance of <see cref="RazorViewEngine"/> will search for views.
/// </summary>
/// <remarks>
/// The locations of the views returned from controllers that do not belong to an area.
/// Locations are composite format strings (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx),
/// which contains following indexes:
/// {0} - Action Name
/// {1} - Controller Name
/// The values for these locations are case-sensitive on case-sensitive file systems.
/// For example, the view for the <c>Test</c> action of <c>HomeController</c> should be located at
/// <c>/Views/Home/Test.cshtml</c>. Locations such as <c>/views/home/test.cshtml</c> would not be discovered
/// </remarks>
public virtual IEnumerable<string> ViewLocationFormats { get; } = new[]
{
"/Views/{1}/{0}" + ViewExtension,
"/Views/Shared/{0}" + ViewExtension,
};
/// <summary>
/// Gets the locations where this instance of <see cref="RazorViewEngine"/> will search for views within an
/// area.
/// </summary>
/// <remarks>
/// The locations of the views returned from controllers that belong to an area.
/// Locations are composite format strings (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx),
/// which contains following indexes:
/// {0} - Action Name
/// {1} - Controller Name
/// {2} - Area name
/// The values for these locations are case-sensitive on case-sensitive file systems.
/// For example, the view for the <c>Test</c> action of <c>HomeController</c> should be located at
/// <c>/Views/Home/Test.cshtml</c>. Locations such as <c>/views/home/test.cshtml</c> would not be discovered
/// </remarks>
public virtual IEnumerable<string> AreaViewLocationFormats { get; } = new[]
{
"/Areas/{2}/Views/{1}/{0}" + ViewExtension,
"/Areas/{2}/Views/Shared/{0}" + ViewExtension,
"/Views/Shared/{0}" + ViewExtension,
};
/// <summary>
/// A cache for results of view lookups.
/// </summary>
protected IMemoryCache ViewLookupCache { get; }
/// <summary>
/// Gets the case-normalized route value for the specified route <paramref name="key"/>.
/// </summary>
/// <param name="context">The <see cref="ActionContext"/>.</param>
/// <param name="key">The route key to lookup.</param>
/// <returns>The value corresponding to the key.</returns>
/// <remarks>
/// The casing of a route value in <see cref="ActionContext.RouteData"/> is determined by the client.
/// This making constructing paths for view locations in a case sensitive file system unreliable. Using the
/// <see cref="Abstractions.ActionDescriptor.RouteValueDefaults"/> for attribute routes and
/// <see cref="Abstractions.ActionDescriptor.RouteConstraints"/> for traditional routes to get route values
/// produces consistently cased results.
/// </remarks>
public static string GetNormalizedRouteValue(ActionContext context, string key)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
object routeValue;
if (!context.RouteData.Values.TryGetValue(key, out routeValue))
{
return null;
}
var actionDescriptor = context.ActionDescriptor;
string normalizedValue = null;
if (actionDescriptor.AttributeRouteInfo != null)
{
object match;
if (actionDescriptor.RouteValueDefaults.TryGetValue(key, out match))
{
normalizedValue = match?.ToString();
}
}
else
{
// Perf: Avoid allocations
for (var i = 0; i < actionDescriptor.RouteConstraints.Count; i++)
{
var constraint = actionDescriptor.RouteConstraints[i];
if (string.Equals(constraint.RouteKey, key, StringComparison.Ordinal))
{
if (constraint.KeyHandling == RouteKeyHandling.DenyKey)
{
return null;
}
else
{
normalizedValue = constraint.RouteValue;
}
// Duplicate keys in RouteConstraints are not allowed.
break;
}
}
}
var stringRouteValue = routeValue?.ToString();
if (string.Equals(normalizedValue, stringRouteValue, StringComparison.OrdinalIgnoreCase))
{
return normalizedValue;
}
return stringRouteValue;
}
/// <inheritdoc />
public RazorPageResult FindPage(ActionContext context, string pageName)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (string.IsNullOrEmpty(pageName))
{
throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(pageName));
}
if (IsApplicationRelativePath(pageName) || IsRelativePath(pageName))
{
// A path; not a name this method can handle.
return new RazorPageResult(pageName, Enumerable.Empty<string>());
}
var cacheResult = LocatePageFromViewLocations(context, pageName, isMainPage: false);
if (cacheResult.Success)
{
var razorPage = cacheResult.ViewEntry.PageFactory();
return new RazorPageResult(pageName, razorPage);
}
else
{
return new RazorPageResult(pageName, cacheResult.SearchedLocations);
}
}
/// <inheritdoc />
public RazorPageResult GetPage(string executingFilePath, string pagePath)
{
if (string.IsNullOrEmpty(pagePath))
{
throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(pagePath));
}
if (!(IsApplicationRelativePath(pagePath) || IsRelativePath(pagePath)))
{
// Not a path this method can handle.
return new RazorPageResult(pagePath, Enumerable.Empty<string>());
}
var cacheResult = LocatePageFromPath(executingFilePath, pagePath, isMainPage: false);
if (cacheResult.Success)
{
var razorPage = cacheResult.ViewEntry.PageFactory();
return new RazorPageResult(pagePath, razorPage);
}
else
{
return new RazorPageResult(pagePath, cacheResult.SearchedLocations);
}
}
/// <inheritdoc />
public ViewEngineResult FindView(ActionContext context, string viewName, bool isMainPage)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (string.IsNullOrEmpty(viewName))
{
throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(viewName));
}
if (IsApplicationRelativePath(viewName) || IsRelativePath(viewName))
{
// A path; not a name this method can handle.
return ViewEngineResult.NotFound(viewName, Enumerable.Empty<string>());
}
var cacheResult = LocatePageFromViewLocations(context, viewName, isMainPage);
return CreateViewEngineResult(cacheResult, viewName);
}
/// <inheritdoc />
public ViewEngineResult GetView(string executingFilePath, string viewPath, bool isMainPage)
{
if (string.IsNullOrEmpty(viewPath))
{
throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(viewPath));
}
if (!(IsApplicationRelativePath(viewPath) || IsRelativePath(viewPath)))
{
// Not a path this method can handle.
return ViewEngineResult.NotFound(viewPath, Enumerable.Empty<string>());
}
var cacheResult = LocatePageFromPath(executingFilePath, viewPath, isMainPage);
return CreateViewEngineResult(cacheResult, viewPath);
}
private ViewLocationCacheResult LocatePageFromPath(string executingFilePath, string pagePath, bool isMainPage)
{
var applicationRelativePath = GetAbsolutePath(executingFilePath, pagePath);
var cacheKey = new ViewLocationCacheKey(applicationRelativePath, isMainPage);
ViewLocationCacheResult cacheResult;
if (!ViewLookupCache.TryGetValue(cacheKey, out cacheResult))
{
var expirationTokens = new HashSet<IChangeToken>();
cacheResult = CreateCacheResult(expirationTokens, applicationRelativePath, isMainPage);
var cacheEntryOptions = new MemoryCacheEntryOptions();
cacheEntryOptions.SetSlidingExpiration(_cacheExpirationDuration);
foreach (var expirationToken in expirationTokens)
{
cacheEntryOptions.AddExpirationToken(expirationToken);
}
// No views were found at the specified location. Create a not found result.
if (cacheResult == null)
{
cacheResult = new ViewLocationCacheResult(new[] { applicationRelativePath });
}
cacheResult = ViewLookupCache.Set<ViewLocationCacheResult>(
cacheKey,
cacheResult,
cacheEntryOptions);
}
return cacheResult;
}
private ViewLocationCacheResult LocatePageFromViewLocations(
ActionContext actionContext,
string pageName,
bool isMainPage)
{
var controllerName = GetNormalizedRouteValue(actionContext, ControllerKey);
var areaName = GetNormalizedRouteValue(actionContext, AreaKey);
var expanderContext = new ViewLocationExpanderContext(
actionContext,
pageName,
controllerName,
areaName,
isMainPage);
Dictionary<string, string> expanderValues = null;
if (_viewLocationExpanders.Count > 0)
{
expanderValues = new Dictionary<string, string>(StringComparer.Ordinal);
expanderContext.Values = expanderValues;
// Perf: Avoid allocations
for (var i = 0; i < _viewLocationExpanders.Count; i++)
{
_viewLocationExpanders[i].PopulateValues(expanderContext);
}
}
var cacheKey = new ViewLocationCacheKey(
expanderContext.ViewName,
expanderContext.ControllerName,
expanderContext.AreaName,
expanderContext.IsMainPage,
expanderValues);
ViewLocationCacheResult cacheResult;
if (!ViewLookupCache.TryGetValue(cacheKey, out cacheResult))
{
_logger.ViewLookupCacheMiss(cacheKey.ViewName, cacheKey.ControllerName);
cacheResult = OnCacheMiss(expanderContext, cacheKey);
}
else
{
_logger.ViewLookupCacheHit(cacheKey.ViewName, cacheKey.ControllerName);
}
return cacheResult;
}
/// <inheritdoc />
public string GetAbsolutePath(string executingFilePath, string pagePath)
{
if (string.IsNullOrEmpty(pagePath))
{
// Path is not valid; no change required.
return pagePath;
}
if (IsApplicationRelativePath(pagePath))
{
// An absolute path already; no change required.
return pagePath;
}
if (!IsRelativePath(pagePath))
{
// A page name; no change required.
return pagePath;
}
// Given a relative path i.e. not yet application-relative (starting with "~/" or "/"), interpret
// path relative to currently-executing view, if any.
if (string.IsNullOrEmpty(executingFilePath))
{
// Not yet executing a view. Start in app root.
return "/" + pagePath;
}
// Get directory name (including final slash) but do not use Path.GetDirectoryName() to preserve path
// normalization.
var index = executingFilePath.LastIndexOf('/');
Debug.Assert(index >= 0);
return executingFilePath.Substring(0, index + 1) + pagePath;
}
private ViewLocationCacheResult OnCacheMiss(
ViewLocationExpanderContext expanderContext,
ViewLocationCacheKey cacheKey)
{
// Only use the area view location formats if we have an area token.
var viewLocations = !string.IsNullOrEmpty(expanderContext.AreaName) ?
AreaViewLocationFormats :
ViewLocationFormats;
for (var i = 0; i < _viewLocationExpanders.Count; i++)
{
viewLocations = _viewLocationExpanders[i].ExpandViewLocations(expanderContext, viewLocations);
}
ViewLocationCacheResult cacheResult = null;
var searchedLocations = new List<string>();
var expirationTokens = new HashSet<IChangeToken>();
foreach (var location in viewLocations)
{
var path = string.Format(
CultureInfo.InvariantCulture,
location,
expanderContext.ViewName,
expanderContext.ControllerName,
expanderContext.AreaName);
cacheResult = CreateCacheResult(expirationTokens, path, expanderContext.IsMainPage);
if (cacheResult != null)
{
break;
}
searchedLocations.Add(path);
}
// No views were found at the specified location. Create a not found result.
if (cacheResult == null)
{
cacheResult = new ViewLocationCacheResult(searchedLocations);
}
var cacheEntryOptions = new MemoryCacheEntryOptions();
cacheEntryOptions.SetSlidingExpiration(_cacheExpirationDuration);
foreach (var expirationToken in expirationTokens)
{
cacheEntryOptions.AddExpirationToken(expirationToken);
}
return ViewLookupCache.Set<ViewLocationCacheResult>(cacheKey, cacheResult, cacheEntryOptions);
}
private ViewLocationCacheResult CreateCacheResult(
HashSet<IChangeToken> expirationTokens,
string relativePath,
bool isMainPage)
{
var factoryResult = _pageFactory.CreateFactory(relativePath);
if (factoryResult.ExpirationTokens != null)
{
for (var i = 0; i < factoryResult.ExpirationTokens.Count; i++)
{
expirationTokens.Add(factoryResult.ExpirationTokens[i]);
}
}
if (factoryResult.Success)
{
// Only need to lookup _ViewStarts for the main page.
var viewStartPages = isMainPage ?
GetViewStartPages(relativePath, expirationTokens) :
EmptyViewStartLocationCacheItems;
return new ViewLocationCacheResult(
new ViewLocationCacheItem(factoryResult.RazorPageFactory, relativePath),
viewStartPages);
}
return null;
}
private IReadOnlyList<ViewLocationCacheItem> GetViewStartPages(
string path,
HashSet<IChangeToken> expirationTokens)
{
var viewStartPages = new List<ViewLocationCacheItem>();
foreach (var viewStartPath in ViewHierarchyUtility.GetViewStartLocations(path))
{
var result = _pageFactory.CreateFactory(viewStartPath);
if (result.ExpirationTokens != null)
{
for (var i = 0; i < result.ExpirationTokens.Count; i++)
{
expirationTokens.Add(result.ExpirationTokens[i]);
}
}
if (result.Success)
{
// Populate the viewStartPages list so that _ViewStarts appear in the order the need to be
// executed (closest last, furthest first). This is the reverse order in which
// ViewHierarchyUtility.GetViewStartLocations returns _ViewStarts.
viewStartPages.Insert(0, new ViewLocationCacheItem(result.RazorPageFactory, viewStartPath));
}
}
return viewStartPages;
}
private ViewEngineResult CreateViewEngineResult(ViewLocationCacheResult result, string viewName)
{
if (!result.Success)
{
return ViewEngineResult.NotFound(viewName, result.SearchedLocations);
}
var page = result.ViewEntry.PageFactory();
var viewStarts = new IRazorPage[result.ViewStartEntries.Count];
for (var i = 0; i < viewStarts.Length; i++)
{
var viewStartItem = result.ViewStartEntries[i];
viewStarts[i] = viewStartItem.PageFactory();
}
var view = new RazorView(this, _pageActivator, viewStarts, page, _htmlEncoder);
return ViewEngineResult.Found(viewName, view);
}
private static bool IsApplicationRelativePath(string name)
{
Debug.Assert(!string.IsNullOrEmpty(name));
return name[0] == '~' || name[0] == '/';
}
private static bool IsRelativePath(string name)
{
Debug.Assert(!string.IsNullOrEmpty(name));
// Though ./ViewName looks like a relative path, framework searches for that view using view locations.
return name.EndsWith(ViewExtension, StringComparison.OrdinalIgnoreCase);
}
}
}