add get_context_data and render methods to Nav (#39)

Author: joshuadavidthomas

CHANGELOG.md

@@ -18,6 +18,16 @@ and this project attempts to adhere to [Semantic Versioning](https://semver.org/
 
 ## [Unreleased]
 
+### Added
+
+- The `Nav` class now has two new methods: `get_context_data` and `render`. These methods are used to render the navigation to a template. These new methods give greater flexibility for customizing the rendering of the navigation, as they can be overridden when defining a new `Nav`.
+  - `Nav.get_context_data` method takes a Django `HttpRequest` object and returns a dictionary of context data that can be used to render the navigation to a template.
+  - `Nav.render` method takes a Django `HttpRequest` object and an optional template name and renders the navigation to a template, returning the rendered template as a string.
+
+### Removed
+
+- `Nav.render_from_request` method has been removed. This was only used within the template tag to render a `Nav` template from an `HttpRequest` object. It has been removed in favor of the new `Nav.get_context_data` and `Nav.render` methods.
+
 ## [0.3.0]
 
 ### Added

src/django_simple_nav/nav.py

@@ -18,18 +18,19 @@ class Nav:
     template_name: str = field(init=False)
     items: list[NavGroup | NavItem] = field(init=False)
 
-    @classmethod
-    def render_from_request(
-        cls, request: HttpRequest, template_name: str | None = None
-    ) -> str:
+    def get_context_data(self, request: HttpRequest) -> dict[str, Any]:
         items = [
             RenderedNavItem(item, request)
-            for item in cls.items
+            for item in self.items
             if check_item_permissions(item, request.user)  # type: ignore[arg-type]
         ]
+        return {"items": items}
+
+    def render(self, request: HttpRequest, template_name: str | None = None) -> str:
+        context = self.get_context_data(request)
         return render_to_string(
-            template_name=template_name or cls.template_name,
-            context={"items": items},
+            template_name=template_name or self.template_name,
+            context=context,
         )
 
 

src/django_simple_nav/templatetags/django_simple_nav.py

@@ -39,10 +39,10 @@ def render(self, context):
             ) from err
 
         if isinstance(self.nav, str):
-            nav = import_string(self.nav)
+            nav = import_string(self.nav)()
         else:
             nav = self.nav
 
-        assert hasattr(nav, "render_from_request")
+        assert hasattr(nav, "render")
 
-        return nav.render_from_request(context["request"], self.template_name)
+        return nav.render(context["request"], self.template_name)

tests/test_nav.py

@@ -50,16 +50,18 @@ def test_nav_render(user, expected_count, req):
         user = baker.make(get_user_model())
 
     req.user = user
-    rendered_template = DummyNav.render_from_request(req)
+
+    rendered_template = DummyNav().render(req)
 
     assert count_anchors(rendered_template) == expected_count
 
 
-def test_dotted_path_rendering(req):
+def test_dotted_path_nav_render(req):
     req.user = baker.make(get_user_model())
+
     nav = import_string("tests.navs.DummyNav")
 
-    assert nav.render_from_request(req)
+    assert nav().render(req)
 
 
 @pytest.mark.parametrize(
@@ -88,15 +90,15 @@ def test_nav_render_with_permissions(req, permission, expected_count):
     user.save()
 
     req.user = user
-    rendered_template = DummyNav.render_from_request(req)
+    rendered_template = DummyNav().render(req)
 
     assert count_anchors(rendered_template) == expected_count
 
 
-def test_nav_render_from_request_with_template_name(req):
+def test_nav_render_with_template_name(req):
     req.user = AnonymousUser()
 
-    rendered_template = DummyNav.render_from_request(req, "tests/alternate.html")
+    rendered_template = DummyNav().render(req, "tests/alternate.html")
 
     assert "This is an alternate template." in rendered_template
 
@@ -185,3 +187,35 @@ def test_extra_context_builtins(req):
     assert rendered_group_item.permissions == ["is_staff"]
     assert rendered_group_item.extra_context == {"foo": "bar"}
     assert rendered_group_item.foo == "bar"
+
+
+def test_get_context_data(req):
+    req.user = baker.make(get_user_model())
+
+    context = DummyNav().get_context_data(req)
+
+    assert context["items"]
+
+
+def test_get_context_data_override(req):
+    class OverrideNav(DummyNav):
+        def get_context_data(self, request):
+            return {"foo": "bar"}
+
+    req.user = baker.make(get_user_model())
+
+    context = OverrideNav().get_context_data(req)
+
+    assert context["foo"] == "bar"
+
+
+def test_get_context_data_override_render(req):
+    class OverrideNav(DummyNav):
+        def get_context_data(self, request):
+            return {"foo": "bar"}
+
+    req.user = baker.make(get_user_model())
+
+    rendered_template = OverrideNav().render(req)
+
+    assert count_anchors(rendered_template) == 0