Provide a more intelligent routing fallback for Blazor apps that only falls back if the route matches a routable component

[danroth27]

The Blazor fallback logic always falls back to the specified route even if the original route doesn't match any routable components. This can be problematic in some cases, like in ASP.NET to ASP.NET Core app migration scenarios where you want to allow any unhandled requests to be proxied elsewhere. The Cocoon project currently uses some custom logic to identify all of the routable components and then only falls back for the component routes. We'll need something similar to support migrating to Blazor in our own incremental migration support based on YARP. We could provide some helpers that make this logic easier.

[SteveSandersonMS]

Sounds fine.

Implementation note: this would need to be an option, not a new default fallback behavior, because in general developers aren't required to use the built-in routing system and they might have a custom one of their own. We wouldn't be able to detect which URLs are matched by a custom router.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 7 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[SteveSandersonMS]

We have this now.

@javiercn Do you feel the current implementation is sufficient for this to count as "done"? If so we can close it.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[javiercn]

@danroth27 I am going to close this one as this is the way Blazor Web works.