access subapp routes via <app-name>:<route-name>

[samuelcolvin]

From aio-libs/aiohttp-jinja2#163

I think sub app routes should be available via subapp:view-name, which would require a route_name argument to add_subapp.

This would roughly mirror django routing and would make stuff like the url() jinja function work with subapps.

It would also make all url_for calls refering to subapps more succinct.

I think @asvetlov has some thoughts on implementation.

[asvetlov]

Hmm. I not sure if subapp:view-name syntax should be a part of aiohttp or just aiohttp_jinja2.
Opinions?

[samuelcolvin]

For me this should definitely be part of aiohttp. There are numerous situation other than templates where it can be useful to declare routes via a simple string.

Just to give a few random examples:

• an API framework might have a URL(route_name) field which converts a pk int to the url for that item
• a menu might be declared via a list of tuples [('account:details', 'My Account'), ('main:dashbaord', 'Dashboard')]

and lots of others, these don't work if there's no simple immutable reference for a route.

[ansrivas]

I also think this could be a part of subapp() implementation. Because if the context is not known, aiohttp_jinja2.setup() will be required to be setup for all the sub apps, like this:

    app.add_subapp(r'/api/v1/todo', todos_app)
    app['todos_app'] = todos_app

    aiohttp_jinja2.setup(todos_app,
                         loader=jinja2.PackageLoader('app', 'templates'))

    app.router.add_static('/static/',
                          path=str(PROJECT_ROOT / 'static'),
                          name='static')```

[asvetlov]

Unfortunately url dispatcher doesn't know about applications stack.
If you want to have such functionality in aiohttp you need adding request.url_for() method.