from urllib.parse import parse_qs, urlparse
[docs]
def param_from_path(name: str, path: str) -> str:
"""
Retrieve any query parameter from a path.
Raises ValueError if path is not a valid URL path or if it does not contain
exactly one query parameter named `name`. Multiple parameters with that
name are not supported and will result in ValueError, as it hints to a
misconfiguration.
Example::
>>> schema_from_path("schema", "/chats?schema=onegov_town6-meggen")
'onegov_town6-meggen
"""
url = urlparse(path)
query = parse_qs(url.query)
if name not in query:
raise ValueError(
f"No parameter named {name} found in path: '{path}'."
)
if len(query[name]) != 1:
raise ValueError(
f"There must only be one instance of '{name}' in path: '{path}'."
)
return query[name][0]