8👍
I think to write a middleware, because otherwise the exception isn’t available in the 500.html
http://docs.djangoproject.com/en/dev/topics/http/middleware/#process-exception
class ProcessExceptionMiddleware(object):
def process_exception(self, request, exception):
t = Template("500 Error: {{ exception }}")
response_html = t.render(Context({'exception' : exception }))
response = http.HttpResponse(response_html)
response.status_code = 500
return response
22👍
If you are looking for a way to get a plain text error page when using curl
, you
need to add the HTTP header X-Requested-With
with value XMLHttpRequest
, e.g.
curl -H 'X-Requested-With: XMLHttpRequest' http://example.com/some/url/
Explanation: this is because Django uses the is_ajax
method to determine whether or not to return as plain text or as HTML. is_ajax
in turn looks at X-Requested-With
.
Update
Since django version 3.1, error reporting ignores the X-Requested-With
header. Instead, set the Accept
header on the request to any valid value which does not include the text/html
mime type.
e.g.
curl -H 'Accept: application/json;charset=utf-8' http://example.comp/some/url
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8👍
There’s a setting DEBUG_PROPAGATE_EXCEPTIONS which will force Django not to wrap the exceptions, so you can see them, e.g. in devserver logs.
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2👍
This is an improvement on Yuji’s answer, which provides a stacktrace, more instructions (for us django newbies) and is simpler.
Put this code in a file somewhere in your application, e.g. PROJECT_ROOT/MAIN_APP/middleware/exceptions.py
, and make sure you have an empty __init__.py
in the same directory.
import traceback
from django.http import HttpResponse
class PlainExceptionsMiddleware(object):
def process_exception(self, request, exception):
return HttpResponse(traceback.format_exc(exception), content_type="text/plain", status=500)
Now edit your settings.py
and find MIDDLEWARE_CLASSES = (
. Add another entry so it is like this:
MIDDLEWARE_CLASSES = (
# (all the previous entries)
# Plain text exception pages.
'MAIN_APP.middleware.exceptions.PlainExceptionsMiddleware',
)
Restart django and you are good to go!
User-agent aware formatting.
If you’re like me and developing an app and a website both backed by django, you probably want to show plain text error pages to the app, and the nice formatted ones to the browser. A simple way to to that is to check the user agent:
import traceback
from django.http import HttpResponse
class PlainExceptionsMiddleware(object):
def process_exception(self, request, exception):
if "HTTP_USER_AGENT" in request.META and "chrome" in request.META["HTTP_USER_AGENT"].lower():
return
return HttpResponse(traceback.format_exc(exception), content_type="text/plain", status=500)
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0👍
Building off of Timmmm’s answer, I had to make several modifications for it to work in Django 3.1:
Create a file somewhere in your application, such as YOUR_APP_NAME/middleware/exceptions.py
and paste the following code:
import traceback
from django.http import HttpResponse, HttpRequest
class PlainExceptionsMiddleware:
def __init__(self, get_response):
self.get_response = get_response
def __call__(self, request):
return self.get_response(request)
def process_exception(self, request: HttpRequest, exception: Exception):
if "HTTP_USER_AGENT" in request.META and "chrome" in request.META["HTTP_USER_AGENT"].lower():
return
print(traceback.format_exc())
return HttpResponse(repr(exception), content_type="text/plain", status=500)
It is not necessary to create an __init__.py
file in the middleware
folder.
In settings.py
, add the following item to the end of the MIDDLEWARE variable, so that it looks like:
MIDDLEWARE = [
# ...
'YOUR_APP_NAME.middleware.exceptions.PlainExceptionsMiddleware'
]
Now, if "HTTP_USER_AGENT" and "chrome" are in the request header, this middleware doesn’t do anything, so Django returns an HTML response as usual. Otherwise, it returns a plain-text representation of the error as a response (e.g., ValueError("Field 'id' expected a number but got 'undefined'.")
) and prints out the traceback to the Django console, as Django normally would. Of course, you can instead return the full traceback as your response.