Methods of classes cannot be used as blueprint routes

[penn5]

Describe the bug
Unable to define routes in classes

Code snippet

class MyApp:
    def __init__(self):
        self.bp = Blueprint("app")
        self.bp.add_route(self.route, "/route")

    def route(self, request):
        return text("hi")

Expected behavior
Accessing /route says hi

Actual behavior
Including the blueprint fails with because trying to assign __blueprintname__ on a method, but methods cannot have arbitrary attributes assigned.

Environment (please complete the following information):
19.12.2, and master

Additional context
Introduced in #1445

[ahopkins]

What is the motivation for this style api? Blueprints work really well in modules.

[penn5]

What is the motivation for this style api? Blueprints work really well in modules.

I want to pass in some objects, and as we are in the middle of a refactor, I don't want it to be tied to any specific import - I want the database to be injected through the class constructor, rather than an import.

[ashleysommer]

Hi @penn5
There is a workaround which doesn't involve hacking the sanic route mechanism.
You can turn the method into a function using functools.partial and functools.wraps like this:

from functools import partial, wraps
class MyApp:
    def __init__(self):
        self.bp = Blueprint("app")
        handler = wraps(self.route)(partial(self.route))
        self.bp.add_route(handler, "/route")

    def route(self, request):
        return text("hi")

I've tested this, and it works exactly as expected. (And actually I will keep this in mind to implement in one of my applications in the future.)