--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libervia/pages/_browser/cache.py	Fri Aug 14 09:31:32 2020 +0200
@@ -0,0 +1,156 @@
+from browser import window
+from browser.local_storage import storage
+from javascript import JSON
+from dialog import notification
+from bridge import Bridge
+
+session_uuid = window.session_uuid
+bridge = Bridge()
+
+# XXX: we don't use browser.object_storage because it is affected by
+#   https://github.com/brython-dev/brython/issues/1467 and mixing local_storage.storage
+#   and object_storage was resulting in weird behaviour (keys found in one not in the
+#   other)
+
+
+class Cache:
+
+    def __init__(self):
+        try:
+            cache = storage['libervia_cache']
+        except KeyError:
+            self.request_data_from_backend()
+        else:
+            cache = JSON.parse(cache)
+            if cache['metadata']['session_uuid'] != session_uuid:
+                print("data in cache are not valid for this session, resetting")
+                del storage['libervia_cache']
+                self.request_data_from_backend()
+            else:
+                self._cache = cache
+                print("storage cache is used")
+
+    @property
+    def roster(self):
+        return self._cache['roster']
+
+    @property
+    def identities(self):
+        return self._cache['identities']
+
+    def update(self):
+        # FIXME: we use window.JSON as a workaround to
+        #   https://github.com/brython-dev/brython/issues/1467
+        print(f"updating: {self._cache}")
+        storage['libervia_cache'] = window.JSON.stringify(self._cache)
+        print("cache stored")
+
+    def _store_if_complete(self):
+        self._completed_count -= 1
+        if self._completed_count == 0:
+            del self._completed_count
+            self.update()
+
+    def getContactsCb(self, contacts):
+        print("roster received")
+        roster = self._cache['roster']
+        for contact_jid, attributes, groups in contacts:
+            roster[contact_jid] = {
+                'attributes': attributes,
+                'groups': groups,
+            }
+        self._store_if_complete()
+
+    def identitiesBaseGetCb(self, identities_raw):
+        print("base identities received")
+        identities = JSON.parse(identities_raw)
+        self._cache['identities'].update(identities)
+        self._store_if_complete()
+
+    def request_failed(self, exc, message):
+        notification.show(message.format(exc=exc), "error")
+        self._store_if_complete()
+
+    def request_data_from_backend(self):
+        self._cache = {
+            'metadata': {
+                "session_uuid": session_uuid,
+            },
+            'roster': {},
+            'identities': {},
+        }
+        self._completed_count = 2
+        print("requesting roster to backend")
+        bridge.getContacts(
+            callback=self.getContactsCb,
+            errback=lambda e: self.request_failed(e, "Can't get contacts: {exc}")
+        )
+        print("requesting base identities to backend")
+        bridge.identitiesBaseGet(
+            callback=self.identitiesBaseGetCb,
+            errback=lambda e: self.request_failed(e, "Can't get base identities: {exc}")
+        )
+
+    def _fill_identities_cb(self, new_identities_raw, callback):
+        new_identities = JSON.parse(new_identities_raw)
+        print(f"new identities: {new_identities.keys()}")
+        self._cache['identities'].update(new_identities)
+        self.update()
+        if callback:
+            callback()
+
+    def fill_identities(self, entities, callback=None):
+        """Check that identities for identites exist, request them otherwise"""
+        to_get = {e for e in entities if e not in self._cache['identities']}
+        if to_get:
+            bridge.identitiesGet(
+                list(to_get),
+                ['avatar', 'nicknames'],
+                callback=lambda identities: self._fill_identities_cb(
+                    identities, callback),
+                errback=lambda failure_: notification.show(
+                    f"Can't get identities: {failure_}",
+                    "error"
+                )
+            )
+        else:
+            # we already have all identities
+            print("no missing identity")
+            if callback:
+                callback()
+
+    def match_identity(self, entity_jid, text, identity=None):
+        """Returns True if a text match an entity identity
+
+        identity will be matching if its jid or any of its name contain text
+        @param entity_jid: jid of the entity to check
+        @param text: text to use for filtering. Must be in lowercase and stripped
+        @param identity: identity data
+            if None, it will be retrieved if jid is not matching
+        @return: True if entity is matching
+        """
+        if text in entity_jid:
+            return True
+        if identity is None:
+            try:
+                identity = self.identities[entity_jid]
+            except KeyError:
+                print(f"missing identity: {entity_jid}")
+                return False
+        return any(text in n.lower() for n in identity['nicknames'])
+
+    def matching_identities(self, text):
+        """Return identities corresponding to a text
+
+        """
+        text = text.lower().strip()
+        for entity_jid, identity in self._cache['identities'].items():
+            if ((text in entity_jid
+                 or any(text in n.lower() for n in identity['nicknames'])
+                 )):
+                yield entity_jid
+
+
+cache = Cache()
+roster = cache.roster
+identities = cache.identities