Merge branch 'master' into aureplop/kfet_cms

kfet/utils.py

@@ -1,4 +1,11 @@
 import math
+import json
+
+from django.core.cache import cache
+from django.core.serializers.json import DjangoJSONEncoder
+
+from channels.channel import Group
+from channels.generic.websockets import JsonWebsocketConsumer
 
 from .config import kfet_config
 
@@ -8,3 +15,101 @@ def to_ukf(balance, is_cof=False):
     subvention = kfet_config.subvention_cof
     grant = (1 + subvention / 100) if is_cof else 1
     return math.floor(balance * 10 * grant)
+
+# Storage
+
+class CachedMixin:
+    """Object with cached properties.
+
+    Attributes:
+        cached (dict): Keys are cached properties. Associated value is the
+            returned default by getters in case the key is missing from cache.
+        cache_prefix (str): Used to prefix keys in cache.
+
+    """
+    cached = {}
+    cache_prefix = ''
+
+    def __init__(self, cache_prefix=None, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        if cache_prefix is not None:
+            self.cache_prefix = cache_prefix
+
+    def cachekey(self, attr):
+        return '{}__{}'.format(self.cache_prefix, attr)
+
+    def __getattr__(self, attr):
+        if attr in self.cached:
+            return cache.get(self.cachekey(attr), self.cached.get(attr))
+        elif hasattr(super(), '__getattr__'):
+            return super().__getattr__(attr)
+        else:
+            raise AttributeError("can't get attribute")
+
+    def __setattr__(self, attr, value):
+        if attr in self.cached:
+            cache.set(self.cachekey(attr), value)
+        elif hasattr(super(), '__setattr__'):
+            super().__setattr__(attr, value)
+        else:
+            raise AttributeError("can't set attribute")
+
+    def clear_cache(self):
+        cache.delete_many([
+            self.cachekey(attr) for attr in self.cached.keys()
+        ])
+
+
+# Consumers
+
+class DjangoJsonWebsocketConsumer(JsonWebsocketConsumer):
+    """Custom Json Websocket Consumer.
+
+    Encode to JSON with DjangoJSONEncoder.
+
+    """
+
+    @classmethod
+    def encode_json(cls, content):
+        return json.dumps(content, cls=DjangoJSONEncoder)
+
+
+class PermConsumerMixin:
+    """Add support to check permissions on consumers.
+
+    Attributes:
+        perms_connect (list): Required permissions to connect to this
+            consumer.
+
+    message.user is appended as argument to each connection_groups method call.
+
+    """
+    http_user = True  # Enable message.user
+    perms_connect = []
+
+    def connect(self, message, **kwargs):
+        """Check permissions on connection."""
+        if message.user.has_perms(self.perms_connect):
+            super().connect(message, **kwargs)
+        else:
+            self.close()
+
+    def raw_connect(self, message, **kwargs):
+        # Same as original raw_connect method of JsonWebsocketConsumer
+        # We add user to connection_groups call.
+        groups = self.connection_groups(user=message.user, **kwargs)
+        for group in groups:
+            Group(group, channel_layer=message.channel_layer).add(message.reply_channel)
+        self.connect(message, **kwargs)
+
+    def raw_disconnect(self, message, **kwargs):
+        # Same as original raw_connect method of JsonWebsocketConsumer
+        # We add user to connection_groups call.
+        groups = self.connection_groups(user=message.user, **kwargs)
+        for group in groups:
+            Group(group, channel_layer=message.channel_layer).discard(message.reply_channel)
+        self.disconnect(message, **kwargs)
+
+    def connection_groups(self, user, **kwargs):
+        """`message.user` is available as `user` arg. Original behavior."""
+        super().connection_groups(user, user, **kwargs)