Add tab for user list

apps/permission/templatetags/perms.py

@@ -4,6 +4,7 @@
 from django.contrib.contenttypes.models import ContentType
 from django.template.defaultfilters import stringfilter
 from django import template
+from note.models import Transaction
 from note_kfet.middlewares import get_current_authenticated_user, get_current_session
 from permission.backends import PermissionBackend
 
@@ -21,9 +22,7 @@ def not_empty_model_list(model_name):
         return True
     if session.get("not_empty_model_list_" + model_name, None):
         return session.get("not_empty_model_list_" + model_name, None) == 1
-    spl = model_name.split(".")
-    ct = ContentType.objects.get(app_label=spl[0], model=spl[1])
-    qs = ct.model_class().objects.filter(PermissionBackend.filter_queryset(user, ct, "view")).all()
+    qs = model_list(model_name)
     session["not_empty_model_list_" + model_name] = 1 if qs.exists() else 2
     return session.get("not_empty_model_list_" + model_name) == 1
 
@@ -41,18 +40,55 @@ def not_empty_model_change_list(model_name):
         return True
     if session.get("not_empty_model_change_list_" + model_name, None):
         return session.get("not_empty_model_change_list_" + model_name, None) == 1
-    spl = model_name.split(".")
-    ct = ContentType.objects.get(app_label=spl[0], model=spl[1])
-    qs = ct.model_class().objects.filter(PermissionBackend.filter_queryset(user, ct, "change"))
+    qs = model_list(model_name, "change")
     session["not_empty_model_change_list_" + model_name] = 1 if qs.exists() else 2
     return session.get("not_empty_model_change_list_" + model_name) == 1
 
 
+@stringfilter
+def model_list(model_name, t="view"):
+    """
+    Return the queryset of all visible instances of the given model.
+    """
+    user = get_current_authenticated_user()
+    if user is None:
+        return False
+    spl = model_name.split(".")
+    ct = ContentType.objects.get(app_label=spl[0], model=spl[1])
+    qs = ct.model_class().objects.filter(PermissionBackend.filter_queryset(user, ct, t)).all()
+    return qs
+
+
 def has_perm(perm, obj):
     return PermissionBackend().has_perm(get_current_authenticated_user(), perm, obj)
 
 
+def can_create_transaction():
+    """
+    :return: True iff the authenticated user can create a transaction.
+    """
+    user = get_current_authenticated_user()
+    session = get_current_session()
+    if user is None:
+        return False
+    elif user.is_superuser and session.get("permission_mask", 0) >= 42:
+        return True
+    if session.get("can_create_transaction", None):
+        return session.get("can_create_transaction", None) == 1
+
+    empty_transaction = Transaction(
+        source=user.note,
+        destination=user.note,
+        quantity=1,
+        amount=0,
+        reason="Check permissions",
+    )
+    session["can_create_transaction"] = PermissionBackend().has_perm(user, "note.add_transaction", empty_transaction)
+    return session.get("can_create_transaction") == 1
+
+
 register = template.Library()
 register.filter('not_empty_model_list', not_empty_model_list)
 register.filter('not_empty_model_change_list', not_empty_model_change_list)
+register.filter('model_list', model_list)
 register.filter('has_perm', has_perm)