Makes razor views (.cshtml) files reloadable #34248
Description
Follow up to dotnet/runtime#54633 to support reloading razor files
Proposed API
namespace Microsoft.AspNetCore.Razor.Hosting
{
+ [AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
+ public sealed class RazorFileIdentifierAttribute : Attribute
+ {
+ public RazorFileIdentifierAttribute(string identifier);
+ public string Identifier { get; }
+ }
}When a reloadable type is reloaded, the compiler tells us what type was reloaded, but not what it is replacing. It's up to the system to determine what's being replaced. For Razor, we can use the path as a way to do this (this is fairly similar to what runtime compilation does). In our current implementation, razor creates an attribute that tells it what it's path is, but this is an assembly level attribute that is not updated on a hot reload event:
[assembly: global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(AspNetCoreGeneratedDocument.Views_Home_Index), @"mvc.1.0.view", @"/Views/Home/Index.cshtml")]The proposal is to add a type level attribute that we can have instead:
+ [global::System.Runtime.CompilerServices.CreateNewOnMetadataUpdateAttribute] // Reloadable type
+ [global::Microsoft.AspNetCore.Razor.Hosting.RazorFileIdentifierAttribute(@"/Views/Home/Index.cshtml")] // This attribute can be used to determine what file needs to be replaced.
internal sealed class Views_Home_Index : global::Microsoft.AspNetCore.Mvc.Razor.RazorPage<dynamic>Usage examples
This is a compiler generated attribute that we do not expect users to use
Alternative designs
We could remove the restriction that prevents RazorCompiledItemAttribute only apply to attributes and additionally apply it to types:
[assembly: global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(AspNetCoreGeneratedDocument.Views_Home_Index), @"mvc.1.0.view", @"/Views/Home/Index.cshtml")]
[global::Microsoft.AspNetCore.Razor.Hosting.RazorCompiledItemAttribute(typeof(AspNetCoreGeneratedDocument.Views_Home_Index), @"mvc.1.0.view", @"/Views/Home/Index.cshtml")]
internal sealed class Views_Home_Index ...
{
}Risks
n/a