File Based Routing for Minimal APIs/Blazor

[divyeshio]

Starting a new project with minimal apis is great experience, but as projects grows apis require structuring. Wouldn't it be great if the structure of the files/folders depicted the routes. Frameworks like Next.js and Tanstack already have this feature. And it is a great experience indeed. Was wondering if we could have something similar in .Net, it would make the DX even better.

Some addtional features :

• Scaffolding : In Tanstack router, when you create a new file in routes folder, it generates writes code that is used for routing something like scaffolding, may be we can use source generators for this.
• Type safe routing : You get typesafety when you're referring to routes from anywhere in the application. Once you have used it, you will miss this feature everywhere. Might not be much useful in minimal apis but could be useful in Blazor (quickly looked up Navlink can use it)

[gfoidl]

@davidfowl PTAL and share your thoughts here (I think you checked such approaches before when IIRC).

[divyeshio]

@gfoidl @davidfowl I vibe-coded a quick prototype here : https://github.com/divyeshio/FileBasedRouting.

It works as following :

1. Routes is a special folder, under which all static methods will be registered as minimal api routes automatically.
2. In case someone wants to change the method (by default GET), they can use existing Http attributes like HttpPost, HttpPut, etc.
3. Attributes can also be used to break out of the convention and pass arbitrary route and it will be still registered as minimal api route.

Note : This works only for non-AOT scenarios because RDG kicks in AOT mode and since we can't chain source generators this gives runtime exceptions in those cases. @captainsafia Any thoughts on this?

[davidfowl]

I'm not a fan of file based routing. Razor pages and Blazor components let you define the route at the top of the file. That scales better as the routing syntax doesn't need to be reverse engineered from riles on disk nor do you need an alernative way to describe things that already can be described using the existing syntax.

[divyeshio]

Fair enough for Razor pages and Blazor components. But How do you structure a minimal api project with hundreds of routes? Can you share of any public available example of that scales well?

[davidfowl]

Are you talking about where to put the routes or are you talking about auto discovery?

[captainsafia]

I'm actually a bit of a fan of file-based routing and enjoyed using it from back when I was building more things with Next.JS. @davidfowl's comment about it not scaling well because there's only so much of a routing system that you can replicate on disk is spot on, but I find this constraint actually better for helping people structure more sensible APIs.

Note : This works only for non-AOT scenarios because RDG kicks in AOT mode and since we can't chain source generators this gives runtime exceptions in those cases. @captainsafia Any thoughts on this?

There's no elegant way around this at the moment, although I do have some ideas about restructuring the way we do endpoint discovery and RequestDelegate construction in minimal APIs that should make hookups like this much more feasible in the future.