text: import time
  
  import django
  from django.http import HttpResponseNotAllowed, HttpResponseForbidden, HttpResponse, HttpResponseBadRequest
  from django.core.urlresolvers import reverse
  from django.core.cache import cache
  from django import get_version as django_version
  from django.core.mail import send_mail, mail_admins
  from django.conf import settings
  from django.utils.translation import ugettext as _
  from django.template import loader, TemplateDoesNotExist
  from django.contrib.sites.models import Site
  from decorator import decorator
  
  from datetime import datetime, timedelta
  
  __version__ = '0.2.3rc1'
  
  def get_version():
      return __version__
  
  def format_error(error):
      return u"Piston/%s (Django %s) crash report:\n\n%s" % \
          (get_version(), django_version(), error)
  
  class rc_factory(object):
      """
      Status codes.
      """
      CODES = dict(ALL_OK = ('OK', 200),
                   CREATED = ('Created', 201),
                   ACCEPTED = ('Accepted', 202),
                   DELETED = ('', 204), # 204 says "Don't send a body!"
                   BAD_REQUEST = ('Bad Request', 400),
                   FORBIDDEN = ('Forbidden', 401),
                   NOT_FOUND = ('Not Found', 404),
                   NOT_ACCEPTABLE = ('Not acceptable', 406),
                   DUPLICATE_ENTRY = ('Conflict/Duplicate', 409),
                   NOT_HERE = ('Gone', 410),
                   INTERNAL_ERROR = ('Internal Error', 500),
                   NOT_IMPLEMENTED = ('Not Implemented', 501),
                   THROTTLED = ('Throttled', 503))
  
      def __getattr__(self, attr):
          """
          Returns a fresh `HttpResponse` when getting 
          an "attribute". This is backwards compatible
          with 0.2, which is important.
          """
          try:
              (r, c) = self.CODES.get(attr)
          except TypeError:
              raise AttributeError(attr)
  
          class HttpResponseWrapper(HttpResponse):
              """
              Wrap HttpResponse and make sure that the internal
              _is_string/_base_content_is_iter flag is updated when the
              _set_content method (via the content property) is called
              """
              def _set_content(self, content):
                  """
                  Set the _container and _is_string /
                  _base_content_is_iter properties based on the type of
                  the value parameter. This logic is in the construtor
                  for HttpResponse, but doesn't get repeated when
                  setting HttpResponse.content although this bug report
                  (feature request) suggests that it should:
                  http://code.djangoproject.com/ticket/9403
                  """
                  is_string = False
                  if not isinstance(content, basestring) and hasattr(content, '__iter__'):
                      self._container = content
                  else:
                      self._container = [content]
                      is_string = True
                  if django.VERSION >= (1, 4):
                      self._base_content_is_iter = not is_string
                  else:
                      self._is_string = is_string
  
              content = property(HttpResponse._get_content, _set_content)            
  
          return HttpResponseWrapper(r, content_type='text/plain', status=c)
      
  rc = rc_factory()
      
  class FormValidationError(Exception):
      def __init__(self, form):
          self.form = form
  
  class HttpStatusCode(Exception):
      def __init__(self, response):
          self.response = response
  
  def validate(v_form, operation='POST'):
      @decorator
      def wrap(f, self, request, *a, **kwa):
          form = v_form(getattr(request, operation), request.FILES)
      
          if form.is_valid():
              setattr(request, 'form', form)
              return f(self, request, *a, **kwa)
          else:
              raise FormValidationError(form)
      return wrap
  
  def throttle(max_requests, timeout=60*60, extra=''):
      """
      Simple throttling decorator, caches
      the amount of requests made in cache.
      
      If used on a view where users are required to
      log in, the username is used, otherwise the
      IP address of the originating request is used.
      
      Parameters::
       - `max_requests`: The maximum number of requests
       - `timeout`: The timeout for the cache entry (default: 1 hour)
      """
      @decorator
      def wrap(f, self, request, *args, **kwargs):
          if request.user.is_authenticated():
              ident = request.user.username
          else:
              ident = request.META.get('REMOTE_ADDR', None)
      
          if hasattr(request, 'throttle_extra'):
              """
              Since we want to be able to throttle on a per-
              application basis, it's important that we realize
              that `throttle_extra` might be set on the request
              object. If so, append the identifier name with it.
              """
              ident += ':%s' % str(request.throttle_extra)
          
          if ident:
              """
              Preferrably we'd use incr/decr here, since they're
              atomic in memcached, but it's in django-trunk so we
              can't use it yet. If someone sees this after it's in
              stable, you can change it here.
              """
              ident += ':%s' % extra
      
              now = time.time()
              count, expiration = cache.get(ident, (1, None))
  
              if expiration is None:
                  expiration = now + timeout
  
              if count >= max_requests and expiration > now:
                  t = rc.THROTTLED
                  wait = int(expiration - now)
                  t.content = 'Throttled, wait %d seconds.' % wait
                  t['Retry-After'] = wait
                  return t
  
              cache.set(ident, (count+1, expiration), (expiration - now))
      
          return f(self, request, *args, **kwargs)
      return wrap
  
  def coerce_put_post(request):
      """
      Django doesn't particularly understand REST.
      In case we send data over PUT, Django won't
      actually look at the data and load it. We need
      to twist its arm here.
      
      The try/except abominiation here is due to a bug
      in mod_python. This should fix it.
      """
      if request.method == "PUT":
          # Bug fix: if _load_post_and_files has already been called, for
          # example by middleware accessing request.POST, the below code to
          # pretend the request is a POST instead of a PUT will be too late
          # to make a difference. Also calling _load_post_and_files will result 
          # in the following exception:
          #   AttributeError: You cannot set the upload handlers after the upload has been processed.
          # The fix is to check for the presence of the _post field which is set 
          # the first time _load_post_and_files is called (both by wsgi.py and 
          # modpython.py). If it's set, the request has to be 'reset' to redo
          # the query value parsing in POST mode.
          if hasattr(request, '_post'):
              del request._post
              del request._files
          
          try:
              request.method = "POST"
              request._load_post_and_files()
              request.method = "PUT"
          except AttributeError:
              request.META['REQUEST_METHOD'] = 'POST'
              request._load_post_and_files()
              request.META['REQUEST_METHOD'] = 'PUT'
              
          request.PUT = request.POST
  
  
  class MimerDataException(Exception):
      """
      Raised if the content_type and data don't match
      """
      pass
  
  class Mimer(object):
      TYPES = dict()
      
      def __init__(self, request):
          self.request = request
          
      def is_multipart(self):
          content_type = self.content_type()
  
          if content_type is not None:
              return content_type.lstrip().startswith('multipart')
  
          return False
  
      def loader_for_type(self, ctype):
          """
          Gets a function ref to deserialize content
          for a certain mimetype.
          """
          for loadee, mimes in Mimer.TYPES.iteritems():
              for mime in mimes:
                  if ctype.startswith(mime):
                      return loadee
                      
      def content_type(self):
          """
          Returns the content type of the request in all cases where it is
          different than a submitted form - application/x-www-form-urlencoded
          """
          type_formencoded = "application/x-www-form-urlencoded"
  
          ctype = self.request.META.get('CONTENT_TYPE', type_formencoded)
          
          if type_formencoded in ctype:
              return None
          
          return ctype
  
      def translate(self):
          """
          Will look at the `Content-type` sent by the client, and maybe
          deserialize the contents into the format they sent. This will
          work for JSON, YAML, XML and Pickle. Since the data is not just
          key-value (and maybe just a list), the data will be placed on
          `request.data` instead, and the handler will have to read from
          there.
          
          It will also set `request.content_type` so the handler has an easy
          way to tell what's going on. `request.content_type` will always be
          None for form-encoded and/or multipart form data (what your browser sends.)
          """    
          ctype = self.content_type()
          self.request.content_type = ctype
          
          if not self.is_multipart() and ctype:
              loadee = self.loader_for_type(ctype)
              
              if loadee:
                  try:
                      self.request.data = loadee(self.request.raw_post_data)
                          
                      # Reset both POST and PUT from request, as its
                      # misleading having their presence around.
                      self.request.POST = self.request.PUT = dict()
                  except (TypeError, ValueError):
                      # This also catches if loadee is None.
                      raise MimerDataException
              else:
                  self.request.data = None
  
          return self.request
                  
      @classmethod
      def register(cls, loadee, types):
          cls.TYPES[loadee] = types
          
      @classmethod
      def unregister(cls, loadee):
          return cls.TYPES.pop(loadee)
  
  def translate_mime(request):
      request = Mimer(request).translate()
      
  def require_mime(*mimes):
      """
      Decorator requiring a certain mimetype. There's a nifty
      helper called `require_extended` below which requires everything
      we support except for post-data via form.
      """
      @decorator
      def wrap(f, self, request, *args, **kwargs):
          m = Mimer(request)
          realmimes = set()
  
          rewrite = { 'json':   'application/json',
                      'yaml':   'application/x-yaml',
                      'xml':    'text/xml',
                      'pickle': 'application/python-pickle' }
  
          for idx, mime in enumerate(mimes):
              realmimes.add(rewrite.get(mime, mime))
  
          if not m.content_type() in realmimes:
              return rc.BAD_REQUEST
  
          return f(self, request, *args, **kwargs)
      return wrap
  
  require_extended = require_mime('json', 'yaml', 'xml', 'pickle')
      
  def send_consumer_mail(consumer):
      """
      Send a consumer an email depending on what their status is.
      """
      try:
          subject = settings.PISTON_OAUTH_EMAIL_SUBJECTS[consumer.status]
      except AttributeError:
          subject = "Your API Consumer for %s " % Site.objects.get_current().name
          if consumer.status == "accepted":
              subject += "was accepted!"
          elif consumer.status == "canceled":
              subject += "has been canceled."
          elif consumer.status == "rejected":
              subject += "has been rejected."
          else: 
              subject += "is awaiting approval."
  
      template = "piston/mails/consumer_%s.txt" % consumer.status    
      
      try:
          body = loader.render_to_string(template, 
              { 'consumer' : consumer, 'user' : consumer.user })
      except TemplateDoesNotExist:
          """ 
          They haven't set up the templates, which means they might not want
          these emails sent.
          """
          return 
  
      try:
          sender = settings.PISTON_FROM_EMAIL
      except AttributeError:
          sender = settings.DEFAULT_FROM_EMAIL
  
      if consumer.user:
          send_mail(_(subject), body, sender, [consumer.user.email], fail_silently=True)
  
      if consumer.status == 'pending' and len(settings.ADMINS):
          mail_admins(_(subject), body, fail_silently=True)
  
      if settings.DEBUG and consumer.user:
          print "Mail being sent, to=%s" % consumer.user.email
          print "Subject: %s" % _(subject)
          print body
  
  