add decorator to cache dynamically generated data inside a view function

It also add support for the ETag and Last-Modified headers.

authentic2/authsaml2/saml2_endpoints.py

@@ -28,6 +28,7 @@ from authentic2.authsaml2 import signals
 from authentic2.authsaml2.models import *
 from backends import AuthSAML2PersistentBackend, \
         AuthSAML2TransientBackend
+from authentic2.utils import cache_and_validate
 
 __logout_redirection_timeout = getattr(settings, 'IDP_LOGOUT_TIMEOUT', 600)
 
@@ -57,6 +58,7 @@ metadata_map = (
 )
 metadata_options = { 'key': settings.SAML_SIGNATURE_PUBLIC_KEY }
 
+@cache_and_validate(settings.LOCAL_METADATA_CACHE_TIMEOUT)
 def metadata(request):
     '''Endpoint to retrieve the metadata file'''
     logger.info('metadata: return metadata')

authentic2/idp/saml/idff12_endpoints.py

@@ -11,12 +11,14 @@ from django.utils.translation import ugettext as _
 from django.views.decorators.csrf import csrf_exempt
 from django.core.urlresolvers import reverse
 from django.contrib.auth.models import User
+from django.conf import settings
 
 from authentic2.saml.models import LibertyArtifact
 from authentic2.saml.common import get_idff12_metadata, create_idff12_server, \
     load_provider, load_federation, load_session, save_federation, \
     save_session, return_idff12_response, get_idff12_request_message, \
     get_soap_message, return_saml_soap_response
+from authentic2.utils import cache_and_validate
 
 def fill_assertion(request, saml_request, assertion, provider_id):
     '''Stuff an assertion with information extracted from the user record
@@ -49,6 +51,7 @@ def build_assertion(request, login):
     assertion = login.assertion
     fill_assertion(request, login.request, assertion, login.remoteProviderId)
 
+@cache_and_validate(settings.LOCAL_METADATA_CACHE_TIMEOUT)
 def metadata(request):
     '''Return ID-FFv1.2 metadata for our IdP'''
     return HttpResponse(get_idff12_metadata(request, reverse(metadata)),

authentic2/idp/saml/saml2_endpoints.py

@@ -46,6 +46,7 @@ from authentic2.idp import signals as idp_signals
 # from authentic2.idp.models import *
 
 from authentic2.authsaml2.models import SAML2TransientUser
+from authentic2.utils import cache_and_validate
 
 '''SAMLv2 IdP implementation
 
@@ -75,6 +76,7 @@ metadata_map = (
 )
 metadata_options = { 'key': settings.SAML_SIGNATURE_PUBLIC_KEY }
 
+@cache_and_validate(settings.LOCAL_METADATA_CACHE_TIMEOUT)
 def metadata(request):
     '''Endpoint to retrieve the metadata file'''
     logger.info('metadata: return metadata')
@@ -252,6 +254,10 @@ def build_assertion(request, login, nid_format = 'transient', attributes=None):
     else:
         logger.debug("build_assertion: nameID not persistent, no federation management")
         federation = None
+        kwargs = nameid2kwargs(login.assertion.subject.nameID)
+    kwargs['entity_id'] = login.remoteProviderId
+    kwargs['user'] = request.user
+    logger.info('build_assertion: sending nameID %(name_id_format)s:%(name_id_content)s to %(entity_id)s for user %(user)s' % kwargs)
     if attributes:
         logger.debug("build_assertion: add attributes to the assertion")
         saml2_add_attribute_values(login.assertion, attributes)

authentic2/settings.py

@@ -90,6 +90,7 @@ TEMPLATE_CONTEXT_PROCESSORS = (
 
 MIDDLEWARE_CLASSES = (
     'django.middleware.common.CommonMiddleware',
+    'django.middleware.http.ConditionalGetMiddleware',
     'django.contrib.csrf.middleware.CsrfMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.middleware.locale.LocaleMiddleware',
@@ -179,6 +180,7 @@ IDP_BACKENDS = [ ]
 IDP_SAML2 = True
 
 # You MUST changes these keys, they are just for testing !
+LOCAL_METADATA_CACHE_TIMEOUT = 600
 SAML_SIGNATURE_PUBLIC_KEY = '''-----BEGIN CERTIFICATE-----
 MIIDIzCCAgugAwIBAgIJANUBoick1pDpMA0GCSqGSIb3DQEBBQUAMBUxEzARBgNV
 BAoTCkVudHJvdXZlcnQwHhcNMTAxMjE0MTUzMzAyWhcNMTEwMTEzMTUzMzAyWjAV

authentic2/utils.py

@@ -1,4 +1,10 @@
 import time
+import hashlib
+import datetime as dt
+
+from django.views.decorators.http import condition
+from django.conf import settings
+from django.http import HttpResponse
 
 class MWT(object):
     """Memoize With Timeout"""
@@ -37,3 +43,62 @@ class MWT(object):
         func.func_name = f.func_name
 
         return func
+
+
+def cache_and_validate(timeout, hashing=hashlib.md5):
+    '''
+       Decorator to add caching, with support for ETag and Last-modified
+       validation.
+
+       Just give it the time for caching.
+    '''
+    def transform(f):
+        f.cache = dict()
+        def get_content(request, *args, **kwargs):
+            '''
+               Content is kept as
+
+                (last_generation_time, last_modified_time, etag, content)
+
+               inside the f.cache dictionnary
+            '''
+            key=args+tuple(sorted(kwargs.items()))
+            if request.method == 'PURGE' and request.environ.get('REMOTE_ADDR') \
+                    in settings.INTERNAL_IPS:
+                # purge the cache place
+                f.cache.pop(key, None)
+            now = dt.datetime.now()
+            if key in f.cache:
+                date, last_modified, etag, mime_type, old_content = f.cache[key]
+                if now - date < dt.timedelta(seconds=timeout):
+                    return date, last_modified, etag, mime_type, old_content
+                else:
+                    content = f(request, *args, **kwargs)
+                    if old_content == content.content:
+                        data = (now, last_modified, etag, old_content)
+                        return data
+            else:
+                content = f(request, *args, **kwargs)
+            if content.status_code == 200:
+                content_type = content.get('Content-Type', None)
+                data = now, now, hashing(content.content).hexdigest(), content_type, content.content
+                f.cache[key] = data
+            else:
+                data = None, None, None, None, content
+            return data
+        def get_last_modified(request, *args, **kwargs):
+            _, last_modified, _, _, _ = get_content(request, *args, **kwargs)
+            return last_modified
+        def get_etag(request, *args, **kwargs):
+            _, _, etag, _, _ = get_content(request, *args, **kwargs)
+            return etag
+        @condition(etag_func=get_etag, last_modified_func=get_last_modified)
+        def replacement(request, *args, **kwargs):
+            _, _, _, content_type, content = get_content(request, *args, **kwargs)
+            if isinstance(content, basestring):
+                return HttpResponse(content, content_type=content_type)
+            else:
+                return content
+        return replacement
+    return transform
+