Source code for django.views.debug
import functools
import itertools
import re
import sys
import types
import warnings
from pathlib import Path
from django.conf import settings
from django.http import Http404, HttpResponse, HttpResponseNotFound
from django.template import Context, Engine, TemplateDoesNotExist
from django.template.defaultfilters import pprint
from django.urls import resolve
from django.utils import timezone
from django.utils.datastructures import MultiValueDict
from django.utils.encoding import force_str
from django.utils.module_loading import import_string
from django.utils.regex_helper import _lazy_re_compile
from django.utils.version import PY311, get_docs_version
# Minimal Django templates engine to render the error templates
# regardless of the project's TEMPLATES setting. Templates are
# read directly from the filesystem so that the error handler
# works even if the template loader is broken.
DEBUG_ENGINE = Engine(
debug=True,
libraries={"i18n": "django.templatetags.i18n"},
)
def builtin_template_path(name):
"""
Return a path to a builtin template.
Avoid calling this function at the module level or in a class-definition
because __file__ may not exist, e.g. in frozen environments.
"""
return Path(__file__).parent / "templates" / name
class ExceptionCycleWarning(UserWarning):
pass
class CallableSettingWrapper:
"""
Object to wrap callable appearing in settings.
* Not to call in the debug page (#21345).
* Not to break the debug page if the callable forbidding to set attributes
(#23070).
"""
def __init__(self, callable_setting):
self._wrapped = callable_setting
def __repr__(self):
return repr(self._wrapped)
def technical_500_response(request, exc_type, exc_value, tb, status_code=500):
"""
Create a technical server error response. The last three arguments are
the values returned from sys.exc_info() and friends.
"""
reporter = get_exception_reporter_class(request)(request, exc_type, exc_value, tb)
if request.accepts("text/html"):
html = reporter.get_traceback_html()
return HttpResponse(html, status=status_code)
else:
text = reporter.get_traceback_text()
return HttpResponse(
text, status=status_code, content_type="text/plain; charset=utf-8"
)
@functools.lru_cache
def get_default_exception_reporter_filter():
# Instantiate the default filter for the first time and cache it.
return import_string(settings.DEFAULT_EXCEPTION_REPORTER_FILTER)()
def get_exception_reporter_filter(request):
default_filter = get_default_exception_reporter_filter()
return getattr(request, "exception_reporter_filter", default_filter)
def get_exception_reporter_class(request):
default_exception_reporter_class = import_string(
settings.DEFAULT_EXCEPTION_REPORTER
)
return getattr(
request, "exception_reporter_class", default_exception_reporter_class
)
def get_caller(request):
resolver_match = request.resolver_match
if resolver_match is None:
try:
resolver_match = resolve(request.path)
except Http404:
pass
return "" if resolver_match is None else resolver_match._func_path
[docs]
class SafeExceptionReporterFilter:
"""
Use annotations made by the sensitive_post_parameters and
sensitive_variables decorators to filter out sensitive information.
"""
cleansed_substitute = "********************"
hidden_settings = _lazy_re_compile(
"API|TOKEN|KEY|SECRET|PASS|SIGNATURE|HTTP_COOKIE", flags=re.I
)
def cleanse_setting(self, key, value):
"""
Cleanse an individual setting key/value of sensitive content. If the
value is a dictionary, recursively cleanse the keys in that dictionary.
"""
if key == settings.SESSION_COOKIE_NAME:
is_sensitive = True
else:
try:
is_sensitive = self.hidden_settings.search(key)
except TypeError:
is_sensitive = False
if is_sensitive:
cleansed = self.cleansed_substitute
elif isinstance(value, dict):
cleansed = {k: self.cleanse_setting(k, v) for k, v in value.items()}
elif isinstance(value, list):
cleansed = [self.cleanse_setting("", v) for v in value]
elif isinstance(value, tuple):
cleansed = tuple([self.cleanse_setting("", v) for v in value])
else:
cleansed = value
if callable(cleansed):
cleansed = CallableSettingWrapper(cleansed)
return cleansed
def get_safe_settings(self):
"""
Return a dictionary of the settings module with values of sensitive
settings replaced with stars (*********).
"""
settings_dict = {}
for k in dir(settings):
if k.isupper():
settings_dict[k] = self.cleanse_setting(k, getattr(settings, k))
return settings_dict
def get_safe_request_meta(self, request):
"""
Return a dictionary of request.META with sensitive values redacted.
"""
if not hasattr(request, "META"):
return {}
return {k: self.cleanse_setting(k, v) for k, v in request.META.items()}
def get_safe_cookies(self, request):
"""
Return a dictionary of request.COOKIES with sensitive values redacted.
"""
if not hasattr(request, "COOKIES"):
return {}
return {k: self.cleanse_setting(k, v) for k, v in request.COOKIES.items()}
[docs]
def is_active(self, request):
"""
This filter is to add safety in production environments (i.e. DEBUG
is False). If DEBUG is True then your site is not safe anyway.
This hook is provided as a convenience to easily activate or
deactivate the filter on a per request basis.
"""
return settings.DEBUG is False
def get_cleansed_multivaluedict(self, request, multivaluedict):
"""
Replace the keys in a MultiValueDict marked as sensitive with stars.
This mitigates leaking sensitive POST parameters if something like
request.POST['nonexistent_key'] throws an exception (#21098).
"""
sensitive_post_parameters = getattr(request, "sensitive_post_parameters", [])
if self.is_active(request) and sensitive_post_parameters:
multivaluedict = multivaluedict.copy()
for param in sensitive_post_parameters:
if param in multivaluedict:
multivaluedict[param] = self.cleansed_substitute
return multivaluedict
[docs]
def get_post_parameters(self, request):
"""
Replace the values of POST parameters marked as sensitive with
stars (*********).
"""
if request is None:
return {}
else:
sensitive_post_parameters = getattr(
request, "sensitive_post_parameters", []
)
if self.is_active(request) and sensitive_post_parameters:
cleansed = request.POST.copy()
if sensitive_post_parameters == "__ALL__":
# Cleanse all parameters.
for k in cleansed:
cleansed[k] = self.cleansed_substitute
return cleansed
else:
# Cleanse only the specified parameters.
for param in sensitive_post_parameters:
if param in cleansed:
cleansed[param] = self.cleansed_substitute
return cleansed
else:
return request.POST
def cleanse_special_types(self, request, value):
try:
# If value is lazy or a complex object of another kind, this check
# might raise an exception. isinstance checks that lazy
# MultiValueDicts will have a return value.
is_multivalue_dict = isinstance(value, MultiValueDict)
except Exception as e:
return "{!r} while evaluating {!r}".format(e, value)
if is_multivalue_dict:
# Cleanse MultiValueDicts (request.POST is the one we usually care about)
value = self.get_cleansed_multivaluedict(request, value)
return value
[docs]
def get_traceback_frame_variables(self, request, tb_frame):
"""
Replace the values of variables marked as sensitive with
stars (*********).
"""
# Loop through the frame's callers to see if the sensitive_variables
# decorator was used.
current_frame = tb_frame.f_back
sensitive_variables = None
while current_frame is not None:
if (
current_frame.f_code.co_name == "sensitive_variables_wrapper"
and "sensitive_variables_wrapper" in current_frame.f_locals
):
# The sensitive_variables decorator was used, so we take note
# of the sensitive variables' names.
wrapper = current_frame.f_locals["sensitive_variables_wrapper"]
sensitive_variables = getattr(wrapper, "sensitive_variables", None)
break
current_frame = current_frame.f_back
cleansed = {}
if self.is_active(request) and sensitive_variables:
if sensitive_variables == "__ALL__":
# Cleanse all variables
for name in tb_frame.f_locals:
cleansed[name] = self.cleansed_substitute
else:
# Cleanse specified variables
for name, value in tb_frame.f_locals.items():
if name in sensitive_variables:
value = self.cleansed_substitute
else:
value = self.cleanse_special_types(request, value)
cleansed[name] = value
else:
# Potentially cleanse the request and any MultiValueDicts if they
# are one of the frame variables.
for name, value in tb_frame.f_locals.items():
cleansed[name] = self.cleanse_special_types(request, value)
if (
tb_frame.f_code.co_name == "sensitive_variables_wrapper"
and "sensitive_variables_wrapper" in tb_frame.f_locals
):
# For good measure, obfuscate the decorated function's arguments in
# the sensitive_variables decorator's frame, in case the variables
# associated with those arguments were meant to be obfuscated from
# the decorated function's frame.
cleansed["func_args"] = self.cleansed_substitute
cleansed["func_kwargs"] = self.cleansed_substitute
return cleansed.items()
[docs]
class ExceptionReporter:
"""Organize and coordinate reporting on exceptions."""
@property
def html_template_path(self):
return builtin_template_path("technical_500.html")
@property
def text_template_path(self):
return builtin_template_path("technical_500.txt")
def __init__(self, request, exc_type, exc_value, tb, is_email=False):
self.request = request
self.filter = get_exception_reporter_filter(self.request)
self.exc_type = exc_type
self.exc_value = exc_value
self.tb = tb
self.is_email = is_email
self.template_info = getattr(self.exc_value, "template_debug", None)
self.template_does_not_exist = False
self.postmortem = None
def _get_raw_insecure_uri(self):
"""
Return an absolute URI from variables available in this request. Skip
allowed hosts protection, so may return insecure URI.
"""
return "{scheme}://{host}{path}".format(
scheme=self.request.scheme,
host=self.request._get_raw_host(),
path=self.request.get_full_path(),
)
[docs]
def get_traceback_data(self):
"""Return a dictionary containing traceback information."""
if self.exc_type and issubclass(self.exc_type, TemplateDoesNotExist):
self.template_does_not_exist = True
self.postmortem = self.exc_value.chain or [self.exc_value]
frames = self.get_traceback_frames()
for i, frame in enumerate(frames):
if "vars" in frame:
frame_vars = []
for k, v in frame["vars"]:
v = pprint(v)
# Trim large blobs of data
if len(v) > 4096:
v = "%s… <trimmed %d bytes string>" % (v[0:4096], len(v))
frame_vars.append((k, v))
frame["vars"] = frame_vars
frames[i] = frame
unicode_hint = ""
if self.exc_type and issubclass(self.exc_type, UnicodeError):
start = getattr(self.exc_value, "start", None)
end = getattr(self.exc_value, "end", None)
if start is not None and end is not None:
unicode_str = self.exc_value.args[1]
unicode_hint = force_str(
unicode_str[max(start - 5, 0) : min(end + 5, len(unicode_str))],
"ascii",
errors="replace",
)
from django import get_version
if self.request is None:
user_str = None
else:
try:
user_str = str(self.request.user)
except Exception:
# request.user may raise OperationalError if the database is
# unavailable, for example.
user_str = "[unable to retrieve the current user]"
c = {
"is_email": self.is_email,
"unicode_hint": unicode_hint,
"frames": frames,
"request": self.request,
"request_meta": self.filter.get_safe_request_meta(self.request),
"request_COOKIES_items": self.filter.get_safe_cookies(self.request).items(),
"user_str": user_str,
"filtered_POST_items": list(
self.filter.get_post_parameters(self.request).items()
),
"settings": self.filter.get_safe_settings(),
"sys_executable": sys.executable,
"sys_version_info": "%d.%d.%d" % sys.version_info[0:3],
"server_time": timezone.now(),
"django_version_info": get_version(),
"sys_path": sys.path,
"template_info": self.template_info,
"template_does_not_exist": self.template_does_not_exist,
"postmortem": self.postmortem,
}
if self.request is not None:
c["request_GET_items"] = self.request.GET.items()
c["request_FILES_items"] = self.request.FILES.items()
c["request_insecure_uri"] = self._get_raw_insecure_uri()
c["raising_view_name"] = get_caller(self.request)
# Check whether exception info is available
if self.exc_type:
c["exception_type"] = self.exc_type.__name__
if self.exc_value:
c["exception_value"] = str(self.exc_value)
if exc_notes := getattr(self.exc_value, "__notes__", None):
c["exception_notes"] = "\n" + "\n".join(exc_notes)
if frames:
c["lastframe"] = frames[-1]
return c
[docs]
def get_traceback_html(self):
"""Return HTML version of debug 500 HTTP error page."""
with self.html_template_path.open(encoding="utf-8") as fh:
t = DEBUG_ENGINE.from_string(fh.read())
c = Context(self.get_traceback_data(), use_l10n=False)
return t.render(c)
[docs]
def get_traceback_text(self):
"""Return plain text version of debug 500 HTTP error page."""
with self.text_template_path.open(encoding="utf-8") as fh:
t = DEBUG_ENGINE.from_string(fh.read())
c = Context(self.get_traceback_data(), autoescape=False, use_l10n=False)
return t.render(c)
def _get_source(self, filename, loader, module_name):
source = None
if hasattr(loader, "get_source"):
try:
source = loader.get_source(module_name)
except ImportError:
pass
if source is not None:
source = source.splitlines()
if source is None:
try:
with open(filename, "rb") as fp:
source = fp.read().splitlines()
except OSError:
pass
return source
def _get_lines_from_file(
self, filename, lineno, context_lines, loader=None, module_name=None
):
"""
Return context_lines before and after lineno from file.
Return (pre_context_lineno, pre_context, context_line, post_context).
"""
source = self._get_source(filename, loader, module_name)
if source is None:
return None, [], None, []
# If we just read the source from a file, or if the loader did not
# apply tokenize.detect_encoding to decode the source into a
# string, then we should do that ourselves.
if isinstance(source[0], bytes):
encoding = "ascii"
for line in source[:2]:
# File coding may be specified. Match pattern from PEP-263
# (https://www.python.org/dev/peps/pep-0263/)
match = re.search(rb"coding[:=]\s*([-\w.]+)", line)
if match:
encoding = match[1].decode("ascii")
break
source = [str(sline, encoding, "replace") for sline in source]
lower_bound = max(0, lineno - context_lines)
upper_bound = lineno + context_lines
try:
pre_context = source[lower_bound:lineno]
context_line = source[lineno]
post_context = source[lineno + 1 : upper_bound]
except IndexError:
return None, [], None, []
return lower_bound, pre_context, context_line, post_context
def _get_explicit_or_implicit_cause(self, exc_value):
explicit = getattr(exc_value, "__cause__", None)
suppress_context = getattr(exc_value, "__suppress_context__", None)
implicit = getattr(exc_value, "__context__", None)
return explicit or (None if suppress_context else implicit)
def get_traceback_frames(self):
# Get the exception and all its causes
exceptions = []
exc_value = self.exc_value
while exc_value:
exceptions.append(exc_value)
exc_value = self._get_explicit_or_implicit_cause(exc_value)
if exc_value in exceptions:
warnings.warn(
"Cycle in the exception chain detected: exception '%s' "
"encountered again." % exc_value,
ExceptionCycleWarning,
)
# Avoid infinite loop if there's a cyclic reference (#29393).
break
frames = []
# No exceptions were supplied to ExceptionReporter
if not exceptions:
return frames
# In case there's just one exception, take the traceback from self.tb
exc_value = exceptions.pop()
tb = self.tb if not exceptions else exc_value.__traceback__
while True:
frames.extend(self.get_exception_traceback_frames(exc_value, tb))
try:
exc_value = exceptions.pop()
except IndexError:
break
tb = exc_value.__traceback__
return frames
def get_exception_traceback_frames(self, exc_value, tb):
exc_cause = self._get_explicit_or_implicit_cause(exc_value)
exc_cause_explicit = getattr(exc_value, "__cause__", True)
if tb is None:
yield {
"exc_cause": exc_cause,
"exc_cause_explicit": exc_cause_explicit,
"tb": None,
"type": "user",
}
while tb is not None:
# Support for __traceback_hide__ which is used by a few libraries
# to hide internal frames.
if tb.tb_frame.f_locals.get("__traceback_hide__"):
tb = tb.tb_next
continue
filename = tb.tb_frame.f_code.co_filename
function = tb.tb_frame.f_code.co_name
lineno = tb.tb_lineno - 1
loader = tb.tb_frame.f_globals.get("__loader__")
module_name = tb.tb_frame.f_globals.get("__name__") or ""
(
pre_context_lineno,
pre_context,
context_line,
post_context,
) = self._get_lines_from_file(
filename,
lineno,
7,
loader,
module_name,
)
if pre_context_lineno is None:
pre_context_lineno = lineno
pre_context = []
context_line = "<source code not available>"
post_context = []
colno = tb_area_colno = ""
if PY311:
_, _, start_column, end_column = next(
itertools.islice(
tb.tb_frame.f_code.co_positions(), tb.tb_lasti // 2, None
)
)
if start_column and end_column:
underline = "^" * (end_column - start_column)
spaces = " " * (start_column + len(str(lineno + 1)) + 2)
colno = f"\n{spaces}{underline}"
tb_area_spaces = " " * (
4
+ start_column
- (len(context_line) - len(context_line.lstrip()))
)
tb_area_colno = f"\n{tb_area_spaces}{underline}"
yield {
"exc_cause": exc_cause,
"exc_cause_explicit": exc_cause_explicit,
"tb": tb,
"type": "django" if module_name.startswith("django.") else "user",
"filename": filename,
"function": function,
"lineno": lineno + 1,
"vars": self.filter.get_traceback_frame_variables(
self.request, tb.tb_frame
),
"id": id(tb),
"pre_context": pre_context,
"context_line": context_line,
"post_context": post_context,
"pre_context_lineno": pre_context_lineno + 1,
"colno": colno,
"tb_area_colno": tb_area_colno,
}
tb = tb.tb_next
def technical_404_response(request, exception):
"""Create a technical 404 error response. `exception` is the Http404."""
try:
error_url = exception.args[0]["path"]
except (IndexError, TypeError, KeyError):
error_url = request.path_info[1:] # Trim leading slash
try:
tried = exception.args[0]["tried"]
except (IndexError, TypeError, KeyError):
resolved = True
tried = request.resolver_match.tried if request.resolver_match else None
else:
resolved = False
if not tried or ( # empty URLconf
request.path == "/"
and len(tried) == 1
and len(tried[0]) == 1 # default URLconf
and getattr(tried[0][0], "app_name", "")
== getattr(tried[0][0], "namespace", "")
== "admin"
):
return default_urlconf(request)
urlconf = getattr(request, "urlconf", settings.ROOT_URLCONF)
if isinstance(urlconf, types.ModuleType):
urlconf = urlconf.__name__
with builtin_template_path("technical_404.html").open(encoding="utf-8") as fh:
t = DEBUG_ENGINE.from_string(fh.read())
reporter_filter = get_default_exception_reporter_filter()
c = Context(
{
"urlconf": urlconf,
"root_urlconf": settings.ROOT_URLCONF,
"request_path": error_url,
"urlpatterns": tried,
"resolved": resolved,
"reason": str(exception),
"request": request,
"settings": reporter_filter.get_safe_settings(),
"raising_view_name": get_caller(request),
}
)
return HttpResponseNotFound(t.render(c))
def default_urlconf(request):
"""Create an empty URLconf 404 error response."""
with builtin_template_path("default_urlconf.html").open(encoding="utf-8") as fh:
t = DEBUG_ENGINE.from_string(fh.read())
c = Context(
{
"version": get_docs_version(),
}
)
return HttpResponse(t.render(c))
