source/tools/webservices/profilemiddleware.py

   1 # http://www.no-ack.org/2010/12/yet-another-profiling-middleware-for.html
   2
   3 import os
   4 import re
   5 import tempfile
   6 from cStringIO import StringIO
   7
   8 from django.conf import settings
   9 import hotshot
  10 import hotshot.stats
  11
  12 COMMENT_SYNTAX = ((re.compile(r'^application/(.*\+)?xml|text/html$', re.I), '<!--', '-->'),
  13                   (re.compile(r'^application/j(avascript|son)$',     re.I), '/*',   '*/' ))
  14
  15 class ProfileMiddleware(object):
  16     def process_view(self, request, callback, args, kwargs):
  17         # Create a profile, writing into a temporary file.
  18         filename = tempfile.mktemp()
  19         profile = hotshot.Profile(filename)
  20
  21         try:
  22             try:
  23                 # Profile the call of the view function.
  24                 response = profile.runcall(callback, request, *args, **kwargs)
  25
  26                 # If we have got a 3xx status code, further
  27                 # action needs to be taken by the user agent
  28                 # in order to fulfill the request. So don't
  29                 # attach any stats to the content, because of
  30                 # the content is supposed to be empty and is
  31                 # ignored by the user agent.
  32                 if response.status_code // 100 == 3:
  33                     return response
  34
  35                 # Detect the appropriate syntax based on the
  36                 # Content-Type header.
  37                 for regex, begin_comment, end_comment in COMMENT_SYNTAX:
  38                     if regex.match(response['Content-Type'].split(';')[0].strip()):
  39                         break
  40                 else:
  41                     # If the given Content-Type is not
  42                     # supported, don't attach any stats to
  43                     # the content and return the unchanged
  44                     # response.
  45                     return response
  46
  47                 # The response can hold an iterator, that
  48                 # is executed when the content property
  49                 # is accessed. So we also have to profile
  50                 # the call of the content property.
  51                 content = profile.runcall(response.__class__.content.fget, response)
  52             finally:
  53                 profile.close()
  54
  55             # Load the stats from the temporary file and
  56             # write them in a human readable format,
  57             # respecting some optional settings into a
  58             # StringIO object.
  59             stats = hotshot.stats.load(filename)
  60             if getattr(settings, 'PROFILE_MIDDLEWARE_STRIP_DIRS', False):
  61                 stats.strip_dirs()
  62             if getattr(settings, 'PROFILE_MIDDLEWARE_SORT', None):
  63                 stats.sort_stats(*settings.PROFILE_MIDDLEWARE_SORT)
  64             stats.stream = StringIO()
  65             stats.print_stats(*getattr(settings, 'PROFILE_MIDDLEWARE_RESTRICTIONS', []))
  66         finally:
  67             os.unlink(filename)
  68
  69         # Construct an HTML/XML or Javascript comment, with
  70         # the formatted stats, written to the StringIO object
  71         # and attach it to the content of the response.
  72         comment = '\n%s\n\n%s\n\n%s\n' % (begin_comment, stats.stream.getvalue().strip(), end_comment)
  73         response.content = content + comment
  74
  75         # If the Content-Length header is given, add the
  76         # number of bytes we have added to it. If the
  77         # Content-Length header is ommited or incorrect,
  78         # it remains so in order to don't change the
  79         # behaviour of the web server or user agent.
  80         if response.has_header('Content-Length'):
  81             response['Content-Length'] = int(response['Content-Length']) + len(comment)
  82
  83         return response