Mount problem

[15864620573]

from blacksheep import Application

parent = Application()


@parent.router.get("/")
def parent_home():
     return "Hello, from the parent app"
 
 
child = Application()
 
 
@child.router.get("/")
def child_home():
     return "Hello, from the child app"


parent.mount_registry.auto_events = True

parent.mount("/sub", child)

For example, in this example, although it is mounted, it will not start and will give a route conflict error.

Why is that? Isn't it already mounted?

[RobertoPrevato]

Hi @15864620573
Thank You for reporting this issue. It is because of a feature I introduced in the second version of the framework to offer a better user experience, reducing code verbosity and making the API to register normal routes identical to the code API to register Controllers routes. The feature is described here: https://www.neoteroi.dev/blacksheep/routing/#using-the-default-router-and-other-routers

In the second version of the framework, when you don´t specify a router for your application, by default it picks the default router - a singleton instantiated in blacksheep itself.

In your example, both the mounted app and the parent app share the same route. This can be fixed instantiating a specific router for (at least) one of the two applications.

from blacksheep import Application, Router

parent = Application(router=Router())


@parent.router.get("/")
def parent_home():
    return "Hello, from the parent app"


child = Application()


@child.router.get("/")
def child_home():
    return "Hello, from the child app"


parent.mount_registry.auto_events = True

parent.mount("/sub", child)

I will improve the documentation regarding mount to clarify this point, and think of issuing warnings / raising a more specific exception.

[RobertoPrevato]

I forgot to mention, @15864620573, if you want to disable the default singleton router, you can use the Environment Variable APP_DEFAULT_ROUTER and set it to 'false' or '0'.