在MVC-5中,我可以通过访问RouteTable.Routes
在初始启动后编辑routetable
。我希望在MVC-6中做同样的事情,这样我就可以在运行时添加/删除路由(用于CMS)。
在MVC-5中执行此操作的代码为:
using (RouteTable.Routes.GetWriteLock())
{
RouteTable.Routes.Clear();
RouteTable.Routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
RouteTable.Routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
}
但我在MVC-6中找不到RouteTable.Routes
或类似的东西。你知道我如何在运行时仍然可以改变路由收集吗?
例如,当在CMS中创建页面时,我想使用这个原则来添加额外的url。
如果你有一个这样的类:
public class Page
{
public int Id { get; set; }
public string Url { get; set; }
public string Html { get; set; }
}
和一个控制器,比如:
public class CmsController : Controller
{
public ActionResult Index(int id)
{
var page = DbContext.Pages.Single(p => p.Id == id);
return View("Layout", model: page.Html);
}
}
然后,当页面添加到数据库中时,我会重新创建routecollection
var routes = RouteTable.Routes;
using (routes.GetWriteLock())
{
routes.Clear();
foreach(var page in DbContext.Pages)
{
routes.MapRoute(
name: Guid.NewGuid().ToString(),
url: page.Url.TrimEnd('/'),
defaults: new { controller = "Cms", action = "Index", id = page.Id }
);
}
var defaultRoute = routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
}
通过这种方式,我可以向CMS添加不属于约定或严格模板的页面。我可以添加一个带有url /contact
的页面,也可以添加一个带有url /help/faq/how-does-this-work
的页面。
发布于 2015-09-15 21:03:09
答案是,没有合理的方法来做到这一点,即使你找到了一种方法,这也不是一个好的做法。
解决这个问题的不正确方法
基本上,过去的MVC版本的路由配置的作用类似于DI配置-也就是说,您将所有内容都放在composition root中,然后在运行时使用该配置。问题在于,您可能会在运行时将对象推送到配置中(许多人都是这样做的),这不是正确的方法。
现在,配置已经被一个真正的DI容器所取代,这种方法将不再有效。注册步骤现在只能在应用程序启动时完成。
正确的方法
定制路由的正确方法是inherit RouteBase或Route
,这远远超出了MVC类在过去的MVC版本中所能做的。
AspNetCore (以前称为MVC6)有类似的抽象、IRouter和INamedRouter,它们填补了相同的角色。就像它的前身一样,IRouter
只有两个方法需要实现。
namespace Microsoft.AspNet.Routing
{
public interface IRouter
{
// Derives a virtual path (URL) from a list of route values
VirtualPathData GetVirtualPath(VirtualPathContext context);
// Populates route data (including route values) based on the
// request
Task RouteAsync(RouteContext context);
}
}
在此接口中,您可以实现routing - URL的双向特性,以路由值并将值路由到URL。
一个例子:CachedRoute<TPrimaryKey>
下面是一个跟踪和缓存主键到URL一对一映射的示例。它是通用的,我已经测试过,无论主键是int
还是Guid
,它都可以工作。
有一个必须注入的可插拔部分,即ICachedRouteDataProvider
,可以在其中实现对数据库的查询。您还需要提供控制器和操作,因此此路由足够通用,可以通过使用多个实例将多个数据库查询映射到多个操作方法。
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Caching.Memory;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
public class CachedRoute<TPrimaryKey> : IRouter
{
private readonly string _controller;
private readonly string _action;
private readonly ICachedRouteDataProvider<TPrimaryKey> _dataProvider;
private readonly IMemoryCache _cache;
private readonly IRouter _target;
private readonly string _cacheKey;
private object _lock = new object();
public CachedRoute(
string controller,
string action,
ICachedRouteDataProvider<TPrimaryKey> dataProvider,
IMemoryCache cache,
IRouter target)
{
if (string.IsNullOrWhiteSpace(controller))
throw new ArgumentNullException("controller");
if (string.IsNullOrWhiteSpace(action))
throw new ArgumentNullException("action");
if (dataProvider == null)
throw new ArgumentNullException("dataProvider");
if (cache == null)
throw new ArgumentNullException("cache");
if (target == null)
throw new ArgumentNullException("target");
_controller = controller;
_action = action;
_dataProvider = dataProvider;
_cache = cache;
_target = target;
// Set Defaults
CacheTimeoutInSeconds = 900;
_cacheKey = "__" + this.GetType().Name + "_GetPageList_" + _controller + "_" + _action;
}
public int CacheTimeoutInSeconds { get; set; }
public async Task RouteAsync(RouteContext context)
{
var requestPath = context.HttpContext.Request.Path.Value;
if (!string.IsNullOrEmpty(requestPath) && requestPath[0] == '/')
{
// Trim the leading slash
requestPath = requestPath.Substring(1);
}
// Get the page id that matches.
TPrimaryKey id;
//If this returns false, that means the URI did not match
if (!GetPageList().TryGetValue(requestPath, out id))
{
return;
}
//Invoke MVC controller/action
var routeData = context.RouteData;
// TODO: You might want to use the page object (from the database) to
// get both the controller and action, and possibly even an area.
// Alternatively, you could create a route for each table and hard-code
// this information.
routeData.Values["controller"] = _controller;
routeData.Values["action"] = _action;
// This will be the primary key of the database row.
// It might be an integer or a GUID.
routeData.Values["id"] = id;
await _target.RouteAsync(context);
}
public VirtualPathData GetVirtualPath(VirtualPathContext context)
{
VirtualPathData result = null;
string virtualPath;
if (TryFindMatch(GetPageList(), context.Values, out virtualPath))
{
result = new VirtualPathData(this, virtualPath);
}
return result;
}
private bool TryFindMatch(IDictionary<string, TPrimaryKey> pages, IDictionary<string, object> values, out string virtualPath)
{
virtualPath = string.Empty;
TPrimaryKey id;
object idObj;
object controller;
object action;
if (!values.TryGetValue("id", out idObj))
{
return false;
}
id = SafeConvert<TPrimaryKey>(idObj);
values.TryGetValue("controller", out controller);
values.TryGetValue("action", out action);
// The logic here should be the inverse of the logic in
// RouteAsync(). So, we match the same controller, action, and id.
// If we had additional route values there, we would take them all
// into consideration during this step.
if (action.Equals(_action) && controller.Equals(_controller))
{
// The 'OrDefault' case returns the default value of the type you're
// iterating over. For value types, it will be a new instance of that type.
// Since KeyValuePair<TKey, TValue> is a value type (i.e. a struct),
// the 'OrDefault' case will not result in a null-reference exception.
// Since TKey here is string, the .Key of that new instance will be null.
virtualPath = pages.FirstOrDefault(x => x.Value.Equals(id)).Key;
if (!string.IsNullOrEmpty(virtualPath))
{
return true;
}
}
return false;
}
private IDictionary<string, TPrimaryKey> GetPageList()
{
IDictionary<string, TPrimaryKey> pages;
if (!_cache.TryGetValue(_cacheKey, out pages))
{
// Only allow one thread to poplate the data
lock (_lock)
{
if (!_cache.TryGetValue(_cacheKey, out pages))
{
pages = _dataProvider.GetPageToIdMap();
_cache.Set(_cacheKey, pages,
new MemoryCacheEntryOptions()
{
Priority = CacheItemPriority.NeverRemove,
AbsoluteExpirationRelativeToNow = TimeSpan.FromSeconds(this.CacheTimeoutInSeconds)
});
}
}
}
return pages;
}
private static T SafeConvert<T>(object obj)
{
if (typeof(T).Equals(typeof(Guid)))
{
if (obj.GetType() == typeof(string))
{
return (T)(object)new Guid(obj.ToString());
}
return (T)(object)Guid.Empty;
}
return (T)Convert.ChangeType(obj, typeof(T));
}
}
CmsCachedRouteDataProvider
这是数据提供程序的实现,基本上就是您在CMS中需要做的事情。
public interface ICachedRouteDataProvider<TPrimaryKey>
{
IDictionary<string, TPrimaryKey> GetPageToIdMap();
}
public class CmsCachedRouteDataProvider : ICachedRouteDataProvider<int>
{
public IDictionary<string, int> GetPageToIdMap()
{
// Lookup the pages in DB
return (from page in DbContext.Pages
select new KeyValuePair<string, int>(
page.Url.TrimStart('/').TrimEnd('/'),
page.Id)
).ToDictionary(pair => pair.Key, pair => pair.Value);
}
}
用法
在这里,我们在默认路由之前添加路由,并配置其选项。
// Add MVC to the request pipeline.
app.UseMvc(routes =>
{
routes.Routes.Add(
new CachedRoute<int>(
controller: "Cms",
action: "Index",
dataProvider: new CmsCachedRouteDataProvider(),
cache: routes.ServiceProvider.GetService<IMemoryCache>(),
target: routes.DefaultHandler)
{
CacheTimeoutInSeconds = 900
});
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
// Uncomment the following line to add a route for porting Web API 2 controllers.
// routes.MapWebApiRoute("DefaultApi", "api/{controller}/{id?}");
});
这就是它的要点。你仍然可以改进一些事情。
例如,我个人会使用工厂模式,并将存储库注入到CmsCachedRouteDataProvider
的构造函数中,而不是在任何地方硬编码DbContext
。
发布于 2020-01-22 05:20:21
一种简单的方法是,如果发生404错误,则检查this条件:
如果路由列表中存在URL,则重定向到该URL
示例.net核心转到Startup.cs(项目根目录),然后在Configure方法中添加底层代码:
public void Configure(IApplicationBuilder app, IWebHostEnvironment env){
app.UseStatusCodePages(async context =>
{
var redirctPage = pageToRedirect(context);
context.HttpContext.Response.Redirect(redirctPage);
}
...
}
private string pageToRedirect(StatusCodeContext context)
{
var def = "";
if(context.HttpContext.Response.StatusCode==404){
if (context.HttpContext.Request.Path.ToString().ToLower().Contains("/product/"))
{
def = "/Home/Product";
def += context.HttpContext.Request.QueryString;
}
else if (context.HttpContext.Request.Path.ToString().ToLower()=="/news")//or you can call class that load info from DB to redirect
{
def = "/Home/News";
def += context.HttpContext.Request.QueryString;
}
else//404 error page
def = "/Home/Error?statusCode=" + context.HttpContext.Response.StatusCode;
}else //other errors code
def = "/Home/Error?statusCode=" + context.HttpContext.Response.StatusCode;
return def;
}
https://stackoverflow.com/questions/32565768
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