Learn how to use page [route and app model provider conventions](xref:mvc/controllers/application-model#conventions) to control page routing, discovery, and processing in Razor Pages apps.
When you need to configure custom page routes for individual pages, configure routing to pages with the [AddPageRoute convention](#configure-a-page-route) described later in this topic.
To specify a page route, add route segments, or add parameters to a route, use the page's `@page` directive. For more information, see [Custom routes](xref:razor-pages/index#custom-routes).
There are reserved words that can't be used as route segments or parameter names. For more information, see [Routing: Reserved routing names](xref:fundamentals/routing#reserved-routing-names).
[View or download sample code](https://github.com/aspnet/Docs/tree/master/aspnetcore/razor-pages/razor-pages-conventions/sample/) ([how to download](xref:index#how-to-download-a-sample))
| [Model conventions](#model-conventions)<br><br>Conventions.Add<ul><li>IPageRouteModelConvention</li><li>IPageApplicationModelConvention</li></ul> | Add a route template and header to an app's pages. |
| [Page route action conventions](#page-route-action-conventions)<ul><li>AddFolderRouteModelConvention</li><li>AddPageRouteModelConvention</li><li>AddPageRoute</li></ul> | Add a route template to pages in a folder and to a single page. |
| [Page model action conventions](#page-model-action-conventions)<ul><li>AddFolderApplicationModelConvention</li><li>AddPageApplicationModelConvention</li><li>ConfigureFilter (filter class, lambda expression, or filter factory)</li></ul> | Add a header to pages in a folder, add a header to a single page, and configure a [filter factory](xref:mvc/controllers/filters#ifilterfactory) to add a header to an app's pages. |
| [Default page app model provider](#replace-the-default-page-app-model-provider) | Replace the default page model provider to change the conventions for handler names. |
| [Model conventions](#model-conventions)<br><br>Conventions.Add<ul><li>IPageRouteModelConvention</li><li>IPageApplicationModelConvention</li><li>IPageHandlerModelConvention</li></ul> | Add a route template and header to an app's pages. |
| [Page route action conventions](#page-route-action-conventions)<ul><li>AddFolderRouteModelConvention</li><li>AddPageRouteModelConvention</li><li>AddPageRoute</li></ul> | Add a route template to pages in a folder and to a single page. |
| [Page model action conventions](#page-model-action-conventions)<ul><li>AddFolderApplicationModelConvention</li><li>AddPageApplicationModelConvention</li><li>ConfigureFilter (filter class, lambda expression, or filter factory)</li></ul> | Add a header to pages in a folder, add a header to a single page, and configure a [filter factory](xref:mvc/controllers/filters#ifilterfactory) to add a header to an app's pages. |
| [Default page app model provider](#replace-the-default-page-app-model-provider) | Replace the default page model provider to change the conventions for handler names. |
Razor Pages conventions are added and configured using the [AddRazorPagesOptions](/dotnet/api/microsoft.extensions.dependencyinjection.mvcrazorpagesmvcbuilderextensions.addrazorpagesoptions) extension method to [AddMvc](/dotnet/api/microsoft.extensions.dependencyinjection.mvcservicecollectionextensions.addmvc) on the service collection in the `Startup` class. The following convention examples are explained later in this topic:
```csharp
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc()
.AddRazorPagesOptions(options =>
{
options.Conventions.Add( ... );
options.Conventions.AddFolderRouteModelConvention("/OtherPages", model => { ... });
options.Conventions.AddPageRouteModelConvention("/About", model => { ... });
Routes specify an <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel.Order*> for processing (route matching).
| Order | Behavior |
| :--------------: | -------- |
| -1 | The route is processed before other routes are processed. |
| 0 | Order isn't specified (default value). Not assigning `Order` (`Order = null`) defaults the route `Order` to 0 (zero) for processing. |
| 1, 2, … n | Specifies the route processing order. |
Route processing is established by convention:
* Routes are processed in sequential order (-1, 0, 1, 2, … n).
* When routes have the same `Order`, the most specific route is matched first followed by less specific routes.
* When routes with the same `Order` and the same number of parameters match a request URL, routes are processed in the order that they're added to the <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.PageConventionCollection>.
If possible, avoid depending on an established route processing order. Generally, routing selects the correct route with URL matching. If you must set route `Order` properties to route requests correctly, the app's routing scheme is probably confusing to clients and fragile to maintain. Seek to simplify the app's routing scheme. The sample app requires an explicit route processing order to demonstrate several routing scenarios using a single app. However, you should attempt to avoid the practice of setting route `Order` in production apps.
Razor Pages routing and MVC controller routing share an implementation. Information on route order in the MVC topics is available at [Routing to controller actions: Ordering attribute routes](xref:mvc/controllers/routing#ordering-attribute-routes).
Add a delegate for [IPageConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageconvention) to add [model conventions](xref:mvc/controllers/application-model#conventions) that apply to Razor Pages.
Use [Conventions](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.razorpagesoptions.conventions) to create and add an [IPageRouteModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageroutemodelconvention) to the collection of [IPageConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageconvention) instances that are applied during page route model construction.
The <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel.Order*> property for the <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel> is set to `1`. This ensures the following route matching behavior in the sample app:
* A route template for `TheContactPage/{text?}` is added later in the topic. The Contact Page route has a default order of `null` (`Order = 0`), so it matches before the `{globalTemplate?}` route template.
* An `{aboutTemplate?}` route template is added later in the topic. The `{aboutTemplate?}` template is given an `Order` of `2`. When the About page is requested at `/About/RouteDataValue`, "RouteDataValue" is loaded into `RouteData.Values["globalTemplate"]` (`Order = 1`) and not `RouteData.Values["aboutTemplate"]` (`Order = 2`) due to setting the `Order` property.
* An `{otherPagesTemplate?}` route template is added later in the topic. The `{otherPagesTemplate?}` template is given an `Order` of `2`. When any page in the *Pages/OtherPages* folder is requested with a route parameter (for example, `/OtherPages/Page1/RouteDataValue`), "RouteDataValue" is loaded into `RouteData.Values["globalTemplate"]` (`Order = 1`) and not `RouteData.Values["otherPagesTemplate"]` (`Order = 2`) due to setting the `Order` property.
Wherever possible, don't set the `Order`, which results in `Order = 0`. Rely on routing to select the correct route.
Razor Pages options, such as adding [Conventions](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.razorpagesoptions.conventions), are added when MVC is added to the service collection in `Startup.ConfigureServices`. For an example, see the [sample app](https://github.com/aspnet/Docs/tree/master/aspnetcore/razor-pages/razor-pages-conventions/sample/).
Use [Conventions](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.razorpagesoptions.conventions) to create and add an [IPageApplicationModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageapplicationmodelconvention) to the collection of [IPageConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageconvention) instances that are applied during page app model construction.
To demonstrate this and other conventions later in the topic, the sample app includes an `AddHeaderAttribute` class. The class constructor accepts a `name` string and a `values` string array. These values are used in its `OnResultExecuting` method to set a response header. The full class is shown in the [Page model action conventions](#page-model-action-conventions) section later in the topic.
The sample app uses the `AddHeaderAttribute` class to add a header, `GlobalHeader`, to all of the pages in the app:
Use [Conventions](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.razorpagesoptions.conventions) to create and add an [IPageHandlerModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipagehandlermodelconvention) to the collection of [IPageConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageconvention) instances that are applied during page handler model construction.
The default route model provider that derives from [IPageRouteModelProvider](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageroutemodelprovider) invokes conventions which are designed to provide extensibility points for configuring page routes.
Use [AddFolderRouteModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageconventioncollection.addfolderroutemodelconvention) to create and add an [IPageRouteModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageroutemodelconvention) that invokes an action on the [PageRouteModel](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageroutemodel) for all of the pages under the specified folder.
The sample app uses `AddFolderRouteModelConvention` to add an `{otherPagesTemplate?}` route template to the pages in the *OtherPages* folder:
The <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel.Order*> property for the <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel> is set to `2`. This ensures that the template for `{globalTemplate?}` (set earlier in the topic to `1`) is given priority for the first route data value position when a single route value is provided. If a page in the *Pages/OtherPages* folder is requested with a route parameter value (for example, `/OtherPages/Page1/RouteDataValue`), "RouteDataValue" is loaded into `RouteData.Values["globalTemplate"]` (`Order = 1`) and not `RouteData.Values["otherPagesTemplate"]` (`Order = 2`) due to setting the `Order` property.
Wherever possible, don't set the `Order`, which results in `Order = 0`. Rely on routing to select the correct route.
Use [AddPageRouteModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageconventioncollection.addpageroutemodelconvention) to create and add an [IPageRouteModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageroutemodelconvention) that invokes an action on the [PageRouteModel](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageroutemodel) for the page with the specified name.
The sample app uses `AddPageRouteModelConvention` to add an `{aboutTemplate?}` route template to the About page:
The <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel.Order*> property for the <xref:Microsoft.AspNetCore.Mvc.ApplicationModels.AttributeRouteModel> is set to `2`. This ensures that the template for `{globalTemplate?}` (set earlier in the topic to `1`) is given priority for the first route data value position when a single route value is provided. If the About page is requested with a route parameter value at `/About/RouteDataValue`, "RouteDataValue" is loaded into `RouteData.Values["globalTemplate"]` (`Order = 1`) and not `RouteData.Values["aboutTemplate"]` (`Order = 2`) due to setting the `Order` property.
Wherever possible, don't set the `Order`, which results in `Order = 0`. Rely on routing to select the correct route.
## Use a parameter transformer to customize page routes
Page routes generated by ASP.NET Core can be customized using a parameter transformer. A parameter transformer implements `IOutboundParameterTransformer` and transforms the value of parameters. For example, a custom `SlugifyParameterTransformer` parameter transformer changes the `SubscriptionManagement` route value to `subscription-management`.
The `PageRouteTransformerConvention` page route model convention applies a parameter transformer to the folder and file name segments of automatically generated page routes in an app. For example, the Razor Pages file at */Pages/SubscriptionManagement/ViewAll.cshtml* would have its route rewritten from `/SubscriptionManagement/ViewAll` to `/subscription-management/view-all`.
`PageRouteTransformerConvention` only transforms the automatically generated segments of a page route that come from the Razor Pages folder and file name. It doesn't transform route segments added with the `@page` directive. The convention also doesn't transform routes added by <xref:Microsoft.Extensions.DependencyInjection.PageConventionCollectionExtensions.AddPageRoute*>.
The `PageRouteTransformerConvention` is registered as an option in `Startup.ConfigureServices`:
```csharp
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc()
.AddRazorPagesOptions(options =>
{
options.Conventions.Add(
new PageRouteTransformerConvention(
new SlugifyParameterTransformer()));
});
}
public class SlugifyParameterTransformer : IOutboundParameterTransformer
Use [AddPageRoute](/dotnet/api/microsoft.extensions.dependencyinjection.pageconventioncollectionextensions.addpageroute) to configure a route to a page at the specified page path. Generated links to the page use your specified route. `AddPageRoute` uses `AddPageRouteModelConvention` to establish the route.
The sample app creates a route to `/TheContactPage` for *Contact.cshtml*:
The Contact page can also be reached at `/Contact` via its default route.
The sample app's custom route to the Contact page allows for an optional `text` route segment (`{text?}`). The page also includes this optional segment in its `@page` directive in case the visitor accesses the page at its `/Contact` route:
Visit the Contact page at either its ordinary route, `/Contact`, or the custom route, `/TheContactPage`. If you supply an additional `text` route segment, the page shows the HTML-encoded segment that you provide:
The default page model provider that implements [IPageApplicationModelProvider](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageapplicationmodelprovider) invokes conventions which are designed to provide extensibility points for configuring page models. These conventions are useful when building and modifying page discovery and processing scenarios.
For the examples in this section, the sample app uses an `AddHeaderAttribute` class, which is a [ResultFilterAttribute](/dotnet/api/microsoft.aspnetcore.mvc.filters.resultfilterattribute), that applies a response header:
Using conventions, the sample demonstrates how to apply the attribute to all of the pages in a folder and to a single page.
**Folder app model convention**
Use [AddFolderApplicationModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageconventioncollection.addfolderapplicationmodelconvention) to create and add an [IPageApplicationModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageapplicationmodelconvention) that invokes an action on [PageApplicationModel](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageapplicationmodel) instances for all pages under the specified folder.
The sample demonstrates the use of `AddFolderApplicationModelConvention` by adding a header, `OtherPagesHeader`, to the pages inside the *OtherPages* folder of the app:
Use [AddPageApplicationModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageconventioncollection.addpageapplicationmodelconvention) to create and add an [IPageApplicationModelConvention](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.ipageapplicationmodelconvention) that invokes an action on the [PageApplicationModel](/dotnet/api/microsoft.aspnetcore.mvc.applicationmodels.pageapplicationmodel) for the page with the specified name.
[ConfigureFilter](/dotnet/api/microsoft.extensions.dependencyinjection.pageconventioncollectionextensions.configurefilter) configures the specified filter to apply. You can implement a filter class, but the sample app shows how to implement a filter in a lambda expression, which is implemented behind-the-scenes as a factory that returns a filter:
The page app model is used to check the relative path for segments that lead to the Page2 page in the *OtherPages* folder. If the condition passes, a header is added. If not, the `EmptyFilter` is applied.
`EmptyFilter` is an [Action filter](xref:mvc/controllers/filters#action-filters). Since Action filters are ignored by Razor Pages, the `EmptyFilter` no-ops as intended if the path doesn't contain `OtherPages/Page2`.
Request the sample's Page2 page at `localhost:5000/OtherPages/Page2` and inspect the headers to view the result:
[ConfigureFilter](/dotnet/api/microsoft.extensions.dependencyinjection.pageconventioncollectionextensions.configurefilter?view=aspnetcore-2.0#Microsoft_Extensions_DependencyInjection_PageConventionCollectionExtensions_ConfigureFilter_Microsoft_AspNetCore_Mvc_ApplicationModels_PageConventionCollection_System_Func_Microsoft_AspNetCore_Mvc_ApplicationModels_PageApplicationModel_Microsoft_AspNetCore_Mvc_Filters_IFilterMetadata__) configures the specified factory to apply [filters](xref:mvc/controllers/filters) to all Razor Pages.
The sample app provides an example of using a [filter factory](xref:mvc/controllers/filters#ifilterfactory) by adding a header, `FilterFactoryHeader`, with two values to the app's pages:
Razor Pages uses the `IPageApplicationModelProvider` interface to create a [DefaultPageApplicationModelProvider](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.internal.defaultpageapplicationmodelprovider). You can inherit from the default model provider to provide your own implementation logic for handler discovery and processing. The default implementation ([reference source](https://github.com/aspnet/Mvc/blob/rel/2.0.1/src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/DefaultPageApplicationModelProvider.cs)) establishes conventions for *unnamed* and *named* handler naming, which is described below.
**Default unnamed handler methods**
Handler methods for HTTP verbs ("unnamed" handler methods) follow a convention: `On<HTTP verb>[Async]` (appending `Async` is optional but recommended for async methods).
Handler methods provided by the developer ("named" handler methods) follow a similar convention. The handler name appears after the HTTP verb or between the HTTP verb and `Async`: `On<HTTP verb><handler name>[Async]` (appending `Async` is optional but recommended for async methods). For example, methods that process messages might take the naming shown in the table below.
| Example named handler method | Example operation |
| `OnGetMessage`/`OnGetMessageAsync` | Obtain a message. |
| `OnPostMessage`/`OnPostMessageAsync` | POST a message. |
| `OnDeleteMessage`/`OnDeleteMessageAsync` | DELETE a message†. |
| `OnPutMessage`/`OnPutMessageAsync` | PUT a message†. |
| `OnPatchMessage`/`OnPatchMessageAsync` | PATCH a message†. |
†Used for making API calls to the page.
**Customize handler method names**
Assume that you prefer to change the way unnamed and named handler methods are named. An alternative naming scheme is to avoid starting the method names with "On" and use the first word segment to determine the HTTP verb. You can make other changes, such as converting the verbs for DELETE, PUT, and PATCH to POST. Such a scheme provides the method names shown in the following table.
| `PostMessage`/`PostMessageAsync` | POST a message. |
| `DeleteMessage`/`DeleteMessageAsync` | POST a message to delete. |
| `PutMessage`/`PutMessageAsync` | POST a message to put. |
| `PatchMessage`/`PatchMessageAsync` | POST a message to patch. |
†Used for making API calls to the page.
To establish this scheme, inherit from the `DefaultPageApplicationModelProvider` class and override the [CreateHandlerModel](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.internal.defaultpageapplicationmodelprovider.createhandlermodel) method to supply custom logic for resolving [PageModel](/dotnet/api/microsoft.aspnetcore.mvc.razorpages.pagemodel) handler names. The sample app shows you how this is done in its `CustomPageApplicationModelProvider` class:
* The class inherits from `DefaultPageApplicationModelProvider`.
* The `TryParseHandlerMethod` processes a handler to determine the HTTP verb (`httpMethod`) and named handler name (`handlerName`) when creating the `PageHandlerModel`.
* An `Async` postfix is ignored, if present.
* Casing is used to parse the HTTP verb from the method name.
* When the method name (without `Async`) is equal to the HTTP verb name, there's no named handler. The `handlerName` is set to `null`, and the method name is `Get`, `Post`, `Delete`, `Put`, or `Patch`.
* When the method name (without `Async`) is longer than the HTTP verb name, there's a named handler. The `handlerName` is set to `<method name (less 'Async', if present)>`. For example, both "GetMessage" and "GetMessageAsync" yield a handler name of "GetMessage".
* DELETE, PUT, and PATCH HTTP verbs are converted to POST.
Register the `CustomPageApplicationModelProvider` in the `Startup` class:
The page model in *Index.cshtml.cs* shows how the ordinary handler method naming conventions are changed for pages in the app. The ordinary "On" prefix naming used with Razor Pages is removed. The method that initializes the page state is now named `Get`. You can see this convention used throughout the app if you open any page model for any of the pages.
Each of the other methods start with the HTTP verb that describes its processing. The two methods that start with `Delete` would normally be treated as DELETE HTTP verbs, but the logic in `TryParseHandlerMethod` explicitly sets the verb to POST for both handlers.
Note that `Async` is optional between `DeleteAllMessages` and `DeleteMessageAsync`. They're both asynchronous methods, but you can choose to use the `Async` postfix or not; we recommend that you do. `DeleteAllMessages` is used here for demonstration purposes, but we recommend that you name such a method `DeleteAllMessagesAsync`. It doesn't affect the processing of the sample's implementation, but using the `Async` postfix calls out the fact that it's an asynchronous method.
`Async` in the handler method name `DeleteMessageAsync` is factored out by the `TryParseHandlerMethod` for handler matching of POST request to method. The `asp-page-handler` name of `DeleteMessage` is matched to the handler method `DeleteMessageAsync`.
MVC [Action filters](xref:mvc/controllers/filters#action-filters) are ignored by Razor Pages, since Razor Pages use handler methods. Other types of MVC filters are available for you to use: [Authorization](xref:mvc/controllers/filters#authorization-filters), [Exception](xref:mvc/controllers/filters#exception-filters), [Resource](xref:mvc/controllers/filters#resource-filters), and [Result](xref:mvc/controllers/filters#result-filters). For more information, see the [Filters](xref:mvc/controllers/filters) topic.
The Page filter ([IPageFilter](/dotnet/api/microsoft.aspnetcore.mvc.filters.ipagefilter)) is a filter that applies to Razor Pages. For more information, see [Filter methods for Razor Pages](xref:razor-pages/filter).
