Allow context_processors to compose from parent apps.

aiohttp_jinja2/__init__.py

@@ -109,7 +109,8 @@ async def wrapped(*args):
 @web.middleware
 async def context_processors_middleware(request, handler):
 
-    request[REQUEST_CONTEXT_KEY] = {}
+    if REQUEST_CONTEXT_KEY not in request:
+        request[REQUEST_CONTEXT_KEY] = {}
     for processor in request.app[APP_CONTEXT_PROCESSORS_KEY]:
         request[REQUEST_CONTEXT_KEY].update(await processor(request))
     return await handler(request)

tests/test_context_processors.py

@@ -35,6 +35,52 @@ async def processor(request):
     assert 'foo: 1, bar: 2, path: /' == txt
 
 
+async def test_nested_context_processors(aiohttp_client):
+
+    @aiohttp_jinja2.template('tmpl.jinja2')
+    async def func(request):
+        return {'bar': 2}
+
+    subapp = web.Application(middlewares=[
+            aiohttp_jinja2.context_processors_middleware])
+    aiohttp_jinja2.setup(subapp, loader=jinja2.DictLoader(
+        {'tmpl.jinja2':
+         'foo: {{ foo }}, bar: {{ bar }}, baz: {{ baz }}, path: {{ request.path }}'}))
+
+    async def subprocessor(request):
+        return {'foo': 1,
+                'bar': 'should be overwriten'}
+
+    subapp['aiohttp_jinja2_context_processors'] = (
+        aiohttp_jinja2.request_processor,
+        subprocessor,
+    )
+
+    subapp.router.add_get('/', func)
+
+    app = web.Application(middlewares=[
+            aiohttp_jinja2.context_processors_middleware])
+    aiohttp_jinja2.setup(app, loader=jinja2.DictLoader({}))
+
+    async def processor(request):
+        return {'baz': 5}
+
+    app['aiohttp_jinja2_context_processors'] = (
+        aiohttp_jinja2.request_processor,
+        processor,
+    )
+
+    app.add_subapp('/sub/', subapp)
+
+
+    client = await aiohttp_client(app)
+
+    resp = await client.get('/sub/')
+    assert 200 == resp.status
+    txt = await resp.text()
+    assert 'foo: 1, bar: 2, baz: 5, path: /sub/' == txt
+
+
 async def test_context_is_response(aiohttp_client):
 
     @aiohttp_jinja2.template('tmpl.jinja2')