Question

I’m using a third party to send email, and they allow me to categorize my email by adding headers to the emails i send through them.

Is it possible to either add a header to the exception email before it gets sent? Or at least, I’ll managing sending the email by catching the exception in the middleware, but how do I generate the nice email response django sends me on a 500?

EDIT: I know how to add headers to emails, I know how to process exception through middleware. I am interested in how to generate the same email that django sends on exception, so that i can add a header.

Answer 1

1. Subclass AdminEmailHandler (defined in django.utils.log).
2. Configure logging accordingly.

Here is how AdminEmailHandler works:

class AdminEmailHandler(logging.Handler):
    """An exception log handler that emails log entries to site admins.

    If the request is passed as the first argument to the log record,
    request data will be provided in the email report.
    """

    def __init__(self, include_html=False):
        logging.Handler.__init__(self)
        self.include_html = include_html

    def emit(self, record):
        try:
            request = record.request
            subject = '%s (%s IP): %s' % (
                record.levelname,
                (request.META.get('REMOTE_ADDR') in settings.INTERNAL_IPS and 'internal' or 'EXTERNAL'),
                record.msg
            )
            filter = get_exception_reporter_filter(request)
            request_repr = filter.get_request_repr(request)
        except:
            subject = '%s: %s' % (
                record.levelname,
                record.getMessage()
            )
            request = None
            request_repr = "Request repr() unavailable."

        if record.exc_info:
            exc_info = record.exc_info
            stack_trace = '\n'.join(traceback.format_exception(*record.exc_info))
        else:
            exc_info = (None, record.getMessage(), None)
            stack_trace = 'No stack trace available'

        message = "%s\n\n%s" % (stack_trace, request_repr)
        reporter = ExceptionReporter(request, is_email=True, *exc_info)
        html_message = self.include_html and reporter.get_traceback_html() or None
        mail.mail_admins(subject, message, fail_silently=True, html_message=html_message)

---

For reference only: my previous answer.

1. Create a custom middleware: take inspiration from CommonMiddleware in https://code.djangoproject.com/browser/django/trunk/django/middleware/common.py (have a look at process_response)
2. Create a function send_mail_with_exception_header based on https://code.djangoproject.com/browser/django/trunk/django/core/mail/message.py

Here is an example:

# Custom middleware

class MyErrorMiddleware(object):
    def process_response(self, request, response):
        if response.status_code == 404:
            domain = request.get_host()
            referer = request.META.get('HTTP_REFERER', None)
            is_internal = _is_internal_request(domain, referer)
            path = request.get_full_path()
                if referer and not _is_ignorable_404(path) and (is_internal or '?' not in referer):
                    ua = request.META.get('HTTP_USER_AGENT', '<none>')
                    ip = request.META.get('REMOTE_ADDR', '<none>')
                    mail_error("Broken %slink on %s" % ((is_internal and 'INTERNAL ' or ''), domain),
                        "Referrer: %s\nRequested URL: %s\nUser agent: %s\nIP address: %s\n" \
                                  % (referer, request.get_full_path(), ua, ip),
                                  fail_silently=True)
                return response

# Custom mail_error function

def mail_error(subject, message, fail_silently=False, connection=None,
                  html_message=None):
    """Sends a message to the managers, as defined by the MANAGERS setting."""
    if not settings.MANAGERS:
        return

    # put your extra headers here
    mail = EmailMultiAlternatives(u'%s%s' % (settings.EMAIL_SUBJECT_PREFIX, subject),
                message, settings.SERVER_EMAIL, [a[1] for a in settings.MANAGERS],
                connection=connection, header={})
    mail
    if html_message:
        mail.attach_alternative(html_message, 'text/html')
    mail.send(fail_silently=fail_silently)