Highlight active section in navigation. (#13)

Highlight, in the navigation bar, the section of the app that the user is
currently using.

AIPscan/__init__.py

@@ -4,6 +4,7 @@
 from flask_sqlalchemy import SQLAlchemy
 
 from AIPscan.celery import configure_celery
+from AIPscan.navbar import NavBar
 from config import CONFIGS
 
 db = SQLAlchemy()
@@ -34,6 +35,18 @@ def create_app(config_name="default"):
 
         db.create_all()
 
+        # Define navigation bar
+        navbar = NavBar()
+        navbar.add("Archivematica Storage Services", "aggregator.storage_services")
+        navbar.add("AIPs", "reporter.view_aips")
+        navbar.add("Reports", "reporter.reports")
+
+        # Inject navigation bar into templates
+        @app.context_processor
+        def inject_navbar():
+            return dict(navbar=navbar)
+
+        # Set up 404 handling
         @app.errorhandler(404)
         def page_not_found(e):
             return render_template("error/404.html"), 404

AIPscan/navbar.py

@@ -0,0 +1,35 @@
+from flask import session, url_for
+
+
+class NavBarItem:
+    label = ""  # Navigation link text
+    route = ""  # Route ("transfer.index" for example)
+
+    def __init__(self, label, route):
+        self.label = label
+        self.route = route
+
+    def get_url(self):
+        return url_for(self.route)
+
+    def is_active(self, request):
+        # Determine request Blueprint
+        rule = request.url_rule
+        request_blueprint = rule.endpoint.split(".")[0]
+
+        if rule.endpoint == self.route:
+            # Found exact match between route and request
+            return True
+        elif request_blueprint != "reporter":
+            # Determine route Blueprint
+            route_blueprint = self.route.split(".")[0]
+
+            # Found Blueprint-level match between route and request
+            return request_blueprint == route_blueprint
+
+
+class NavBar:
+    items = []
+
+    def add(self, label, route):
+        self.items.append(NavBarItem(label, route))

AIPscan/templates/base.html

@@ -25,15 +25,13 @@
     <a class="navbar-brand" href="/">AIPscan</a>
     <div class="navbar-collapse" id="navbarNavDropdown">
       <ul class="navbar-nav">
-        <li class="nav-item">
-          <a class="nav-link" href="{{ url_for('aggregator.storage_services') }}">Archivematica Storage Services</a>
-        </li>
-        <li class="nav-item">
-          <a class="nav-link" href="{{ url_for('reporter.view_aips') }}">AIPs</a>
-        </li>
-        <li class="nav-item">
-          <a class="nav-link" href="{{ url_for('reporter.reports') }}">Reports</a>
-        </li>
+
+        {% for item in navbar.items %}
+          <li class="nav-item">
+            <a class="nav-link {{ 'active fw-bold' if item.is_active(request) else '' }}" href="{{ item.get_url() }}">{{ item.label }}</a>
+          </li>
+        {% endfor %}
+
         <li class="nav-item">
           <a class="nav-link" href="{{ url_for('api.doc') }}" target="apiframe">API</a>
         </li>