be based on. NETCORE development blog project starblog - (12) razor page dynamic compilation

Series articles

• be based on .NetCore Developing blog projects StarBlog - (1) Why do you need to write your own blog ？

• be based on .NetCore Developing blog projects StarBlog - (2) Environment preparation and project creation

• be based on .NetCore Developing blog projects StarBlog - (3) Model design

• be based on .NetCore Developing blog projects StarBlog - (4) markdown Blog batch import

• be based on .NetCore Developing blog projects StarBlog - (5) Begin to build Web project

• be based on .NetCore Developing blog projects StarBlog - (6) List of blog posts for page development

• be based on .NetCore Developing blog projects StarBlog - (7) Page development article details page

• be based on .NetCore Developing blog projects StarBlog - (8) The classification hierarchy shows

• be based on .NetCore Developing blog projects StarBlog - (9) Batch import of pictures

• be based on .NetCore Developing blog projects StarBlog - (10) Picture waterfall flow

• be based on .NetCore Developing blog projects StarBlog - (11) Implement access statistics

• be based on .NetCore Developing blog projects StarBlog - (12) Razor Page dynamic compilation

• ...

Preface

I haven't updated my blog development notes for some time , Lazy = =..

Take advantage of the weekend , To improve the blog project some details of the function , Then prepare to deploy and go online ~

Originally, this article was to record several functions （ Topic switching 、 Project monitoring 、 Random picture interface ） Implementation of , But when I was writing the page, I found that every time I changed it Razor It needs to be restarted. It's a big trouble , So I stepped on the pit , Then there is this article .

Razor Page dynamic compilation

although .Net6 Some code hot updates are supported , But it's still chicken ribs , Change it all the time Razor Page, but click Apply It still doesn't work ~

I'll use it again .NetCore3.1 The previously used dynamic compilation is better ~

First NuGet install Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation, stay Program.cs Middle configuration

Original addition MVC The service is like this

builder.Services.AddControllersWithViews(
    options => { options.Filters.Add<ResponseWrapperFilter>(); }
)

To such （ Development mode enables dynamic compilation ）

var mvcBuilder = builder.Services.AddControllersWithViews(
    options => { options.Filters.Add<ResponseWrapperFilter>(); }
);
if (builder.Environment.IsDevelopment()) {
    mvcBuilder.AddRazorRuntimeCompilation();
}

It can also be modified without modification C# Code , By means of environment variables , modify launchSettings.json file , Add an environment variable

In this way, the program will be loaded dynamically when it is started RuntimeCompilation.

"environmentVariables": {
    "ASPNETCORE_ENVIRONMENT": "Development",
    "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation"
}

in addition , There are more radical ways , Don't compile when publishing and packaging cshtml file , Easy to modify after publishing Razor page .

In the project profile (xxx.csproj) Middle configuration

<PropertyGroup>
    <RazorCompileOnBuild>false</RazorCompileOnBuild>
    <MvcRazorCompileOnPublish>false</MvcRazorCompileOnPublish>
</PropertyGroup>

So when it is released , be-all Razor Views are not precompiled , And all views will be published together , Convenient for online environment modification Razor page .

Note, however, that in the production environment of the release , Modifying the view file is Will not take effect immediately , Need to restart the program （ about IIS The running environment of the host needs to restart the site ） Will take effect .

You can also configure conditional compilation , For details, please refer to ：https://www.cnblogs.com/thinksea/articles/14772837.html

This is the end of the modification Razor page , preservation , Will automatically recompile , It is convenient to view the effect in real time after modifying the page .

Configure the error after dynamic compilation

I have a problem here , Before .NetCore3.1 I haven't encountered any

Added the error report of the startup program after dynamic compilation

Unhandled exception. System.ArgumentNullException: Value cannot be null. (Parameter 'source')
   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   at System.Linq.Enumerable.OfType[TResult](IEnumerable source)
   at Microsoft.AspNetCore.Mvc.RazorPages.Infrastructure.PageActionDescriptorProvider..ctor(IEnumerable`1 pageRouteModelProviders, IOptions`1 mvcOptionsAccessor, IOptions`1 pag
esOptionsAccessor)
   ... Omit a lot of error messages 
   at Program.<Main>$(String[] args) in StarBlog\StarBlog.Web\Program.cs:line 96

After searching , Find one Github issues：https://github.com/dotnet/aspnetcore/issues/40609

Do you have the 6.0.201 SDK / 6.0.3 Microsoft.AspNetCore.App runtime installed? Patch builds of packages typically require a corresponding version of the runtime to be installed.

Take a look at mine dotnet SDK edition , yes 6.0.101 , Seems to be SDK Of bug, Just update the version ~

（ After ten minutes ） Updated , Sure enough, the problem was solved ！

Reference material

• .Net Core 5.0 Razor precompile , Dynamic compilation , Mixed compilation ：https://www.cnblogs.com/thinksea/articles/14772837.html

• .NET Hot Reload support for ASP.NET Core：https://docs.microsoft.com/en-us/aspnet/core/test/hot-reload?view=aspnetcore-6.0

• Razor file compilation in ASP.NET Core：https://docs.microsoft.com/en-us/aspnet/core/mvc/views/view-compilation?view=aspnetcore-6.0&tabs=visual-studio

• Can't get RazorPageOptions from DI with version 6.0.3 of Mvc.Razor.RuntimeCompilation：https://github.com/dotnet/aspnetcore/issues/40609