Bootstrap 5 Renderer

flask_nav3/__init__.py

@@ -32,6 +32,8 @@ def get_renderer(app, iid):  # noqa: WPS210
     :param app: :class:`~flask.Flask` application to look ``iid`` up on
     :param iid: Internal renderer id-string to look up
     """
+    if iid is None and app.extensions["nav"].bootstrap:
+        iid = "bootstrap"
     renderer = app.extensions.get("nav_renderers", {})[iid]
 
     if isinstance(renderer, tuple):
@@ -99,33 +101,41 @@ class Nav(object):
     """The Flask-Nav extension.
 
     :param app: An optional :class:`~flask.Flask` app to initialize.
+    :param bootstrap: Use bootstrap 5 rendering. Default: False.
     """
 
-    def __init__(self, app=None):
+    def __init__(self, app=None, bootstrap=False):
         """Construct a Nav instance.
 
         Parameters
         ----------
         app : Flask, optional
             The Flask app, by default None
+        bootstrap: boolean
+            Use bootstrap 5 rendering. Default: False.
         """
+        self.bootstrap = bootstrap
         self.elems = ElementRegistry()
 
         # per default, register the simple renderer
         simple = "{0}.renderers".format(__name__), "SimpleRenderer"
+        bootstrap = "{0}.renderers".format(__name__), "BootStrapRenderer"
         self._renderers = [
             ("simple", simple),
+            ("bootstrap", bootstrap),
             (None, simple, False),
         ]
 
         if app:
             self.init_app(app)
 
-    def init_app(self, app):
+    def init_app(self, app, bootstrap=False):
         """Initialize an application.
 
         :param app: A :class:`~flask.Flask` app.
+        :param bootstrap: Use bootstrap 5 rendering. Default: False.
         """
+        self.bootstrap = bootstrap
         if not hasattr(app, "extensions"):
             app.extensions = {}
 

flask_nav3/renderers.py

@@ -92,3 +92,78 @@ def visit_Separator(self, node):
     def visit_Text(self, node):
         """Returns nav-label spans."""
         return tags.span(node.text, _class="nav-label")
+
+
+class BootStrapRenderer(Renderer):
+    """A very basic Bootstrap 5 renderer.
+
+    Renders a navigational structure using ``<nav>`` and ``<ul>`` tags that
+    can be styled using modern CSS.
+
+    :param kwargs: Additional attributes to pass on to the root ``<nav>``-tag.
+    """
+
+    def __init__(self, **kwargs):
+        """Constructor for ``SimpleRenderer``."""
+        self.kwargs = kwargs
+
+    def visit_Link(self, node):
+        """Returns arefs matching url."""
+        return tags.a(node.text, href=node.get_url(), _class="nav-link")
+
+    def visit_Navbar(self, node):
+        """Returns navbar classes."""
+        kwargs = self.kwargs.copy()
+
+        addclass = []
+        if "class" in self.kwargs:
+            addclass = kwargs["class"].split(" ")
+
+        kwargs["class"] = " ".join(addclass + ["navbar", "navbar-expand-lg"])
+
+        cont = tags.nav(**kwargs)
+        ul = cont.add(tags.ul(_class=" ".join(addclass + ["nav"])))
+
+        for item in node.items:
+            ul.add(tags.li(self.visit(item), _class="nav-item"))
+
+        return cont
+
+    def visit_View(self, node):
+        """Returns arefs."""
+        kwargs = {"class": "nav-link"}
+        if node.active:
+            kwargs["_class"] = "nav-link active"
+        return tags.a(
+            node.text,
+            href=node.get_url(),
+            title=node.text,
+            **kwargs,
+        )  # noqa: WPS221
+
+    def visit_Subgroup(self, node):
+        """Returns subgroup divs."""
+        group = tags.ul(_class="dropdown-menu")
+        kwargs = {"data-bs-toggle": "dropdown"}
+        title = tags.a(
+            node.title,
+            href="#",
+            _class="nav-link dropdown-toggle",
+            **kwargs,
+        )
+
+        if node.active:
+            title.attributes["class"] = "nav-link dropdown-toggle active"
+
+        for item in node.items:
+            group.add(tags.li(self.visit(item), _class="dropdown-item"))
+
+        return tags.div(title, group, _class="dropdown")
+
+    def visit_Separator(self, node):
+        """Returns separator hrs."""
+        return tags.hr(_class="dropdown-divider")
+
+    def visit_Text(self, node):
+        """Returns nav-label spans."""
+        return tags.a(node.text, _class="nav-link disabled")