django/core/checks/urls.py
import inspect
from collections import Counter
from django.conf import settings
from django.core.exceptions import ViewDoesNotExist
from . import Error, Tags, Warning, register
@register(Tags.urls)
def check_url_config(app_configs, **kwargs):
if getattr(settings, "ROOT_URLCONF", None):
from django.urls import get_resolver
resolver = get_resolver()
return check_resolver(resolver)
return []
def check_resolver(resolver):
"""
Recursively check the resolver.
"""
check_method = getattr(resolver, "check", None)
if check_method is not None:
return check_method()
elif not hasattr(resolver, "resolve"):
return get_warning_for_invalid_pattern(resolver)
else:
return []
@register(Tags.urls)
def check_url_namespaces_unique(app_configs, **kwargs):
"""
Warn if URL namespaces used in applications aren't unique.
"""
if not getattr(settings, "ROOT_URLCONF", None):
return []
from django.urls import get_resolver
resolver = get_resolver()
all_namespaces = _load_all_namespaces(resolver)
counter = Counter(all_namespaces)
non_unique_namespaces = [n for n, count in counter.items() if count > 1]
errors = []
for namespace in non_unique_namespaces:
errors.append(
Warning(
"URL namespace '{}' isn't unique. You may not be able to reverse "
"all URLs in this namespace".format(namespace),
id="urls.W005",
)
)
return errors
def _load_all_namespaces(resolver, parents=()):
"""
Recursively load all namespaces from URL patterns.
"""
url_patterns = getattr(resolver, "url_patterns", [])
namespaces = [
":".join(parents + (url.namespace,))
for url in url_patterns
if getattr(url, "namespace", None) is not None
]
for pattern in url_patterns:
namespace = getattr(pattern, "namespace", None)
current = parents
if namespace is not None:
current += (namespace,)
namespaces.extend(_load_all_namespaces(pattern, current))
return namespaces
def get_warning_for_invalid_pattern(pattern):
"""
Return a list containing a warning that the pattern is invalid.
describe_pattern() cannot be used here, because we cannot rely on the
urlpattern having regex or name attributes.
"""
if isinstance(pattern, str):
hint = (
"Try removing the string '{}'. The list of urlpatterns should not "
"have a prefix string as the first element.".format(pattern)
)
elif isinstance(pattern, tuple):
hint = "Try using path() instead of a tuple."
else:
hint = None
return [
Error(
"Your URL pattern {!r} is invalid. Ensure that urlpatterns is a list "
"of path() and/or re_path() instances.".format(pattern),
hint=hint,
id="urls.E004",
)
]
@register(Tags.urls)
def check_url_settings(app_configs, **kwargs):
errors = []
for name in ("STATIC_URL", "MEDIA_URL"):
value = getattr(settings, name)
if value and not value.endswith("/"):
errors.append(E006(name))
return errors
def E006(name):
return Error(
"The {} setting must end with a slash.".format(name),
id="urls.E006",
)
@register(Tags.urls)
def check_custom_error_handlers(app_configs, **kwargs):
if not getattr(settings, "ROOT_URLCONF", None):
return []
from django.urls import get_resolver
resolver = get_resolver()
errors = []
# All handlers take (request, exception) arguments except handler500
# which takes (request).
for status_code, num_parameters in [(400, 2), (403, 2), (404, 2), (500, 1)]:
try:
handler = resolver.resolve_error_handler(status_code)
except (ImportError, ViewDoesNotExist) as e:
path = getattr(resolver.urlconf_module, "handler%s" % status_code)
msg = (
"The custom handler{status_code} view '{path}' could not be "
"imported."
).format(status_code=status_code, path=path)
errors.append(Error(msg, hint=str(e), id="urls.E008"))
continue
signature = inspect.signature(handler)
args = [None] * num_parameters
try:
signature.bind(*args)
except TypeError:
msg = (
"The custom handler{status_code} view '{path}' does not "
"take the correct number of arguments ({args})."
).format(
status_code=status_code,
path=handler.__module__ + "." + handler.__qualname__,
args="request, exception" if num_parameters == 2 else "request",
)
errors.append(Error(msg, id="urls.E007"))
return errors