Async rendering support (#393)

Author: Dreamsorcerer

.mypy.ini

@@ -21,4 +21,6 @@ disallow_any_unimported = True
 warn_return_any = True
 
 [mypy-tests.*]
+disallow_any_decorated = False
+disallow_untyped_calls = False
 disallow_untyped_defs = False

aiohttp_jinja2/__init__.py

@@ -10,6 +10,7 @@
     Iterable,
     Mapping,
     Optional,
+    Tuple,
     TypeVar,
     Union,
     cast,
@@ -97,13 +98,12 @@ def get_env(app: web.Application, *, app_key: str = APP_KEY) -> jinja2.Environme
     return cast(jinja2.Environment, app.get(app_key))
 
 
-def render_string(
+def _render_string(
     template_name: str,
     request: web.Request,
     context: Mapping[str, Any],
-    *,
-    app_key: str = APP_KEY,
-) -> str:
+    app_key: str,
+) -> Tuple[jinja2.Template, Mapping[str, Any]]:
     env = request.config_dict.get(app_key)
     if env is None:
         text = (
@@ -126,26 +126,71 @@ def render_string(
         raise web.HTTPInternalServerError(reason=text, text=text)
     if request.get(REQUEST_CONTEXT_KEY):
         context = dict(request[REQUEST_CONTEXT_KEY], **context)
-    text = template.render(context)
-    return text
+    return template, context
 
 
-def render_template(
+def render_string(
     template_name: str,
     request: web.Request,
-    context: Optional[Mapping[str, Any]],
+    context: Mapping[str, Any],
     *,
     app_key: str = APP_KEY,
-    encoding: str = "utf-8",
-    status: int = 200,
-) -> web.Response:
+) -> str:
+    template, context = _render_string(template_name, request, context, app_key)
+    return template.render(context)
+
+
+async def render_string_async(
+    template_name: str,
+    request: web.Request,
+    context: Mapping[str, Any],
+    *,
+    app_key: str = APP_KEY,
+) -> str:
+    template, context = _render_string(template_name, request, context, app_key)
+    return await template.render_async(context)
+
+
+def _render_template(
+    context: Optional[Mapping[str, Any]],
+    encoding: str,
+    status: int,
+) -> Tuple[web.Response, Mapping[str, Any]]:
     response = web.Response(status=status)
     if context is None:
         context = {}
-    text = render_string(template_name, request, context, app_key=app_key)
     response.content_type = "text/html"
     response.charset = encoding
-    response.text = text
+    return response, context
+
+
+def render_template(
+    template_name: str,
+    request: web.Request,
+    context: Optional[Mapping[str, Any]],
+    *,
+    app_key: str = APP_KEY,
+    encoding: str = "utf-8",
+    status: int = 200,
+) -> web.Response:
+    response, context = _render_template(context, encoding, status)
+    response.text = render_string(template_name, request, context, app_key=app_key)
+    return response
+
+
+async def render_template_async(
+    template_name: str,
+    request: web.Request,
+    context: Optional[Mapping[str, Any]],
+    *,
+    app_key: str = APP_KEY,
+    encoding: str = "utf-8",
+    status: int = 200,
+) -> web.Response:
+    response, context = _render_template(context, encoding, status)
+    response.text = await render_string_async(
+        template_name, request, context, app_key=app_key
+    )
     return response
 
 
@@ -197,9 +242,15 @@ async def wrapped(*args: Any) -> web.StreamResponse:
             else:
                 request = args[-1]
 
-            response = render_template(
-                template_name, request, context, app_key=app_key, encoding=encoding
-            )
+            env = request.config_dict.get(app_key)
+            if env and env.is_async:
+                response = await render_template_async(
+                    template_name, request, context, app_key=app_key, encoding=encoding
+                )
+            else:
+                response = render_template(
+                    template_name, request, context, app_key=app_key, encoding=encoding
+                )
             response.set_status(status)
             return response
 

tests/test_simple_renderer.py

@@ -10,14 +10,19 @@
 _T = TypeVar("_T")
 
 
-async def test_func(aiohttp_client):
+@pytest.mark.parametrize("enable_async", (False, True))
+async def test_func(aiohttp_client, enable_async):
     @aiohttp_jinja2.template("tmpl.jinja2")
     async def func(request: web.Request) -> Dict[str, str]:
         return {"head": "HEAD", "text": "text"}
 
     template = "<html><body><h1>{{head}}</h1>{{text}}</body></html>"
     app = web.Application()
-    aiohttp_jinja2.setup(app, loader=jinja2.DictLoader({"tmpl.jinja2": template}))
+    aiohttp_jinja2.setup(
+        app,
+        enable_async=enable_async,
+        loader=jinja2.DictLoader({"tmpl.jinja2": template}),
+    )
 
     app.router.add_route("*", "/", func)
 
@@ -137,16 +142,15 @@ async def func(request):
     assert "<html><body><h1>HEAD</h1>text</body></html>" == txt
 
 
-async def test_render_template(aiohttp_client):
-    async def func(request):
-        return aiohttp_jinja2.render_template(
-            "tmpl.jinja2", request, {"head": "HEAD", "text": "text"}
-        )
-
+async def _test_render_template(func, aiohttp_client, enable_async):
     template = "<html><body><h1>{{head}}</h1>{{text}}</body></html>"
 
     app = web.Application()
-    aiohttp_jinja2.setup(app, loader=jinja2.DictLoader({"tmpl.jinja2": template}))
+    aiohttp_jinja2.setup(
+        app,
+        enable_async=enable_async,
+        loader=jinja2.DictLoader({"tmpl.jinja2": template}),
+    )
 
     app.router.add_route("*", "/", func)
 
@@ -159,6 +163,24 @@ async def func(request):
     assert "<html><body><h1>HEAD</h1>text</body></html>" == txt
 
 
+async def test_render_template(aiohttp_client):
+    async def func(request):
+        return aiohttp_jinja2.render_template(
+            "tmpl.jinja2", request, {"head": "HEAD", "text": "text"}
+        )
+
+    await _test_render_template(func, aiohttp_client, enable_async=False)
+
+
+async def test_render_template_async(aiohttp_client):
+    async def func(request):
+        return await aiohttp_jinja2.render_template_async(
+            "tmpl.jinja2", request, {"head": "HEAD", "text": "text"}
+        )
+
+    await _test_render_template(func, aiohttp_client, enable_async=True)
+
+
 async def test_render_template_custom_status(aiohttp_client):
     async def func(request):
         return aiohttp_jinja2.render_template(