using aiohttp-jinja2 with nested apps about aiohttp-jinja2 HOT 8 CLOSED

This is aiohttp bug, see aio-libs/aiohttp#2550

from aiohttp-jinja2.

While you are right about that bug, this is a bit deeper I guess. The problem here is that the template decorator (actually the render_string() call inside it) uses the request.app variable which is correctly pointing to the blog sub_app in my case. Here I want to inherit the plugin from a parent app without additional setup (which seems fair, if anyone has a different point of view, I'm all ears). I see two options: 1) having render_string() look just in the app that was setup for aiohttp_jinja2 and maybe just check that request.app is a subapp of the setup one (for consistency) or 2) falling back to one of the parent apps in match_info.apps until we found jinja's env. The first choice is difficult as aiohttp_jinja2 is a module and not an object, so we can have a global in the module pointing at the top level app but then we can't override the Env in subapps. Choice number two allows for sub_app to override and setup a different Env and have that picked up if we walk match_info.apps in order from last to first.
What do you think?

from aiohttp-jinja2.

In my mind supapp is completely separated application, it should work without any dependencies from main application.
However for convenience aiohttp_jinja2 could search in parent apps for jinja environment. The behavior should be opt-in controlled by new parameter in setup() function, the param can setup a new subapp state like supapp['aiohttp_jinja2_lookup_in_parents'] = True.

Pull Request is welcome!

from aiohttp-jinja2.

However for convenience aiohttp_jinja2 could search in parent apps for jinja environment. The behavior should be opt-in controlled by new parameter in setup() function, the param can setup a new subapp state like supapp['aiohttp_jinja2_lookup_in_parents'] = True.

So the code should look like this?

root_app = web.Application()
sub_app = web.Application()
root_app.add_subapp('/sub', sub_app)

# should be like this 1)
aiohttp_jinja2.setup(root_app)
aiohttp_jinja2.setup(sub_app, lookup_in_parent=True)

# or like this 2)
aiohttp_jinja2.setup(root_app, propagate_to_subapps=True)

# or even worse (don't mind its just a sarcasm):
aiohttp_jinja2.setup(root_app)
root_app.add_subapp(sub_app, aiohttp_jinja2_lookup_in_parent=True)

With the option 1) one must explicitly call aiohttp_jinja2.setup() so I don't see any reason
why it should become more complicated (to lookup in parent apps) instead of setup isolated environment
for sub-application.
With option 2) it is a bit complicated to set aiohttp_jinja2_lookup_in_parents in sub applications, either
aiohttp should patched to allow callbacks on add_subapp call or some hacks should be made in aiohttp_jinja2.

If we end up with option 1) it could be a better choice to share jinja environment instead of
making @template code more complicated.
Also there is another issue with app instance in environment globals:
https://github.com/aio-libs/aiohttp-jinja2/blob/master/aiohttp_jinja2/__init__.py#L32
It doesn't matter if we share environment or look it up in parent apps, app instance in globals must point to proper application.

from aiohttp-jinja2.

I'll see first if I can solve my problem with a mix of jinja loaders, what I wanted to achive is something like this (I'm experimenting, so before going to work on a feature I want to know if there's a requirement for it): I want to write a blog application, then I want to reuse it as a section of different websites. Now, the blog app can define the post and post list templates, but the general layout and style is defined in the parent website. My problem is that the base template will be in a different package and even if I setup jinja for the subapp I won't be able to access the parent as I don't know the package name or the file system layout before-hand as it changes from site to site. If you have a better idea besides sharing the rendering engine between apps I would be very glad to hear.

from aiohttp-jinja2.

Sharing an engine sounds like robust option.
We can add setup_with_env(app, env) helper for this where env=aiohttp_jinja2.get_env(main_app)

from aiohttp-jinja2.

@espositofulvio
Do you maybe need something like this:

aiohttp_jinja2.setup(
    app,
    loader=jinja2.FileSystemLoader([
        './templates',
        './subapps/subapp1/templates',
        './subapps/subapp2/templates',
    ])
)

from aiohttp-jinja2.

Fixed by #229

from aiohttp-jinja2.