# Copyright The IETF Trust 2007, All Rights Reserved

from django.db import connection
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.http import HttpResponsePermanentRedirect
from ietf.utils.log import log
from ietf.utils.mail import log_smtp_exception
import re
import smtplib
import unicodedata

class SQLLogMiddleware(object):
    def process_response(self, request, response):
	for q in connection.queries:
	    if re.match('(update|insert)', q['sql'], re.IGNORECASE):
		log(q['sql'])
        return response

class SMTPExceptionMiddleware(object):
    def process_exception(self, request, exception):
	if isinstance(exception, smtplib.SMTPException):
            (extype, value, tb) = log_smtp_exception(exception)
	    return render_to_response('email_failed.html', {'exception': extype, 'args': value, 'traceback': "".join(tb)},
		context_instance=RequestContext(request))
	return None

class RedirectTrailingPeriod(object):
    def process_response(self, request, response):
	if response.status_code == 404 and request.path.endswith("."):
	    return HttpResponsePermanentRedirect(request.path.rstrip("."))
	return response

class UnicodeNfkcNormalization(object):
    def process_request(self, request):
        """Do Unicode NFKC normalization to turn ligatures into individual characters.
        This was prompted by somebody actually requesting an url for /wg/ipfix/charter
        where the 'fi' was composed of an \ufb01 ligature...

        There are probably other elements of a request which may need this normalization
        too, but let's put that in as it comes up, rather than guess ahead.
        """
        request.META["PATH_INFO"] = unicodedata.normalize('NFKC', request.META["PATH_INFO"])
        request.path_info = unicodedata.normalize('NFKC', request.path_info)
        return None