I am following this example on passing tokens from HttpContext to components in a SSR application. It mentions the following:
An alternative to assigning the initial state to the TokenProvider in the preceding example is to copy the data into a scoped service within OnInitializedAsync for use across the app.
However, it seems that resolving the scoped service from App.razor causes it to initialized twice:
App.razor:
@inject Service Service
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<base href="/" />
<link rel="stylesheet" href="bootstrap/bootstrap.min.css" />
<link rel="stylesheet" href="app.css" />
<link rel="stylesheet" href="BlazorSandbox.styles.css" />
<link rel="icon" type="image/png" href="favicon.png" />
<HeadOutlet @rendermode="new InteractiveServerRenderMode(prerender: false)" />
</head>
<body>
<Routes @rendermode="new InteractiveServerRenderMode(prerender: false)" />
<script src="_framework/blazor.web.js"></script>
</body>
</html>
@code {
protected override Task OnInitializedAsync()
{
Service.Foo = 123;
return base.OnInitializedAsync();
}
}
Home.razor:
@page "/"
@inject Service Service
<PageTitle>Home</PageTitle>
<h1>Hello, world!</h1>
Service.Foo: @Service.Foo
Service.Foo is 0 here.
I’ve seen similar issues with scoped services getting initialized twice. These were related to prerendering though, which is already disabled in my case. Browsing a bit further through the documentation I could find the following info:
The App component is always rendered statically even if prerendering of a page component is disabled. Therefore, injecting services via the top-level imports file results in resolving two instances of the service in page components.
I am assuming this also applies to services resolved directly via @Inject. Is there any workaround for this? I need to initialize the service from a location where HttpContext is guaranteed to be available. AFAICT this is only the case for App.razor (formerly _Host.cshtml)?
lvde0 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
1