filters: backport selectattr, rejectattr

We want to use jinja2 from wheezy and need to backport two template functions.

2 files changed, 37 insertions, 0 deletions

diff --git a/filters.py b/filters.py
new file mode 100644
index 0000000..b8b0d47
--- /dev/null
+++ b/filters.py
@@ -0,0 +1,36 @@
+from app import app
+from jinja2 import contextfilter
+from jinja2.filters import make_attrgetter
+
+@app.template_filter('selectattr')
+@contextfilter
+def do_selectattr(*args, **kwargs):
+    return _select_or_reject(args, kwargs, lambda x: x)
+
+@app.template_filter('rejectattr')
+@contextfilter
+def do_rejectattr(*args, **kwargs):
+    return _select_or_reject(args, kwargs, lambda x: not x)
+
+def _select_or_reject(args, kwargs, modfunc):
+    context = args[0]
+    seq = args[1]
+
+    try:
+        attr = args[2]
+    except LookupError:
+        raise FilterArgumentError('Missing parameter for attribute name')
+    transfunc = make_attrgetter(context.environment, attr)
+
+    try:
+        name = args[3]
+        args = args[4:]
+        func = lambda item: context.environment.call_test(
+            name, item, args, kwargs)
+    except LookupError:
+        func = bool
+
+    if seq:
+        for item in seq:
+            if modfunc(func(transfunc(item))):
+                yield item
diff --git a/views.py b/views.py
index 5df76f8..01dd5c7 100644
--- a/views.py
+++ b/views.py
@@ -5,6 +5,7 @@ from flask_peewee.utils import get_object_or_404
 from models import Group, Member
 from forms import CreateGroup, DeleteGroup
 from utils import templated
+from filters import *
 
 def get_group_or_404(*query):
     group = get_object_or_404(Group.select().join(Member),