"""
useful context functions, see
http://jinja.pocoo.org/docs/dev/api/#jinja2.contextfunction
"""
import sys
from typing import Any, Dict, Optional, Union
import jinja2
from aiohttp import web
from yarl import URL
if sys.version_info >= (3, 8):
from typing import TypedDict
class _Context(TypedDict, total=False):
app: web.Application
else:
_Context = Dict[str, Any]
@jinja2.pass_context
def url_for(
context: _Context,
__route_name: str,
query_: Optional[Dict[str, str]] = None,
**parts: Union[str, int]
) -> URL:
"""Filter for generating urls.
Usage: {{ url('the-view-name') }} might become "/path/to/view" or
{{ url('item-details', id=123, query_={'active': 'true'}) }}
might become "/items/1?active=true".
"""
app = context["app"]
parts_clean: Dict[str, str] = {}
for key in parts:
val = parts[key]
if isinstance(val, str):
# if type is inherited from str expilict cast to str makes sense
# if type is exactly str the operation is very fast
val = str(val)
elif type(val) is int:
# int inherited classes like bool are forbidden
val = str(val)
else:
raise TypeError(
"argument value should be str or int, "
"got {} -> [{}] {!r}".format(key, type(val), val)
)
parts_clean[key] = val
url = app.router[__route_name].url_for(**parts_clean)
if query_:
url = url.with_query(query_)
return url
@jinja2.pass_context
def static_url(context: _Context, static_file_path: str) -> str:
"""Filter for generating urls for static files.
NOTE: you'll need
to set app['static_root_url'] to be used as the root for the urls returned.
Usage: {{ static('styles.css') }} might become
"/static/styles.css" or "http://mycdn.example.com/styles.css"
"""
app = context["app"]
try:
static_url = app["static_root_url"]
except KeyError:
raise RuntimeError(
"app does not define a static root url "
"'static_root_url', you need to set the url root "
"with app['static_root_url'] = '<static root>'."
) from None
return "{}/{}".format(static_url.rstrip("/"), static_file_path.lstrip("/"))
GLOBAL_HELPERS = dict(
url=url_for,
static=static_url,
)
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