Support default values of viewlet functions.

.travis.yml

@@ -45,14 +45,14 @@ matrix:
       env: TOXENV=py36-django111
     - python: 3.6
       env: TOXENV=py36-django20
-    - python: 3.3
-      env: TOXENV=py33-django15
-    - python: 3.3
-      env: TOXENV=py33-django16
-    - python: 3.3
-      env: TOXENV=py33-django17
-    - python: 3.3
-      env: TOXENV=py33-django18
+#    - python: 3.3
+#      env: TOXENV=py33-django15
+#    - python: 3.3
+#      env: TOXENV=py33-django16
+#    - python: 3.3
+#      env: TOXENV=py33-django17
+#    - python: 3.3
+#      env: TOXENV=py33-django18
     - python: 3.4  # i.e. skip installing 3.5
       env: TOXENV=lint
     - python: 3.4

tox.ini

@@ -4,7 +4,7 @@
 [tox]
 envlist = py26-django{ 13, 14, 15, 16                           },
           py27-django{     14, 15, 16, 17, 18, 19, 110, 111     },
-          py33-django{         15, 16, 17, 18                   },
+#          py33-django{         15, 16, 17, 18                   },
           py34-django{                 17, 18, 19, 110, 111, 20 },
           py35-django{                     18, 19, 110, 111, 20 },
           py36-django{                                  111, 20 }
@@ -33,15 +33,15 @@ deps = django12: Django>=1.2,<1.3
 [testenv:coverage]
 skip_install = true
 passenv = COVERAGE_FILE
-basepython = python3.4
+basepython = python2.7
 commands =
     make coverage
 deps =
     coverage
 
 
 [testenv:lint]
-basepython = python3.4
+basepython = python2.7
 skip_install = true
 commands =
     make lint

viewlet/compat.py

@@ -45,6 +45,20 @@ def get_func_args(func):
     return inspect.getargspec(func).args
 
 
+def get_func_defaults(func):
+    if PY3:
+        params = inspect.signature(func).parameters
+        return dict((k, v.default)
+                    for k, v in params.items()
+                    if v.default != v.empty)
+    spec = inspect.getargspec(func)
+    vals = spec.defaults
+    if not vals:
+        return {}
+    keys = spec.args[-len(vals):]
+    return dict(zip(keys, vals))
+
+
 def import_module(name):
     if sys.version_info < (2, 7):
         if django.VERSION < (1, 7):

viewlet/models.py

@@ -4,7 +4,8 @@
 import warnings
 
 from .cache import get_cache
-from .compat import smart_text, smart_bytes, get_func_args, import_module
+from .compat import smart_text, smart_bytes, get_func_args, \
+    get_func_defaults, import_module
 from .conf import settings
 from .const import DEFAULT_TIMEOUT
 from .loaders import render
@@ -55,6 +56,7 @@ def register(self, func):
         """
         self.viewlet_func = func
         self.viewlet_func_args = get_func_args(func)
+        self.viewlet_func_defaults = get_func_defaults(func)
         self.has_args = len(self.viewlet_func_args) > 1
 
         if not self.name:
@@ -70,8 +72,16 @@ def call_with_refresh(*args, **kwargs):
         return call_with_refresh
 
     def _build_args(self, *args, **kwargs):
-        viewlet_func_kwargs = dict((self.viewlet_func_args[i], args[i]) for i in range(0, len(args)))
-        viewlet_func_kwargs.update(dict((k, kwargs[k]) for k in kwargs if k in self.viewlet_func_args))
+        viewlet_func_kwargs = self.viewlet_func_defaults.copy()
+        viewlet_func_kwargs.update(dict(
+            (self.viewlet_func_args[i], args[i])
+            for i in range(0, len(args))
+        ))
+        viewlet_func_kwargs.update(dict(
+            (k, kwargs[k])
+            for k in kwargs
+            if k in self.viewlet_func_args
+        ))
         return [viewlet_func_kwargs.get(arg) for arg in self.viewlet_func_args]
 
     def _build_cache_key(self, *args):

viewlet/tests/test_viewlet.py

@@ -164,6 +164,11 @@ def test_render_tag(self):
         template = self.get_django_template("<h1>{% viewlet hello_world name= %}</h1>")
         self.assertRaises(TemplateSyntaxError, self.render, template)
 
+    def test_default_value(self):
+        template = self.get_django_template("<h1>{% viewlet hello_nocache %}</h1>")
+        html = self.render(template)
+        self.assertEqual(html.strip(), u'<h1>Hello wurld!\n</h1>')
+
     def test_cached_tag(self):
         template = self.get_django_template("<h1>{% viewlet hello_cached_timestamp 'world' %}</h1>")
         html1 = self.render(template)