Generate menu dynamically for flask application

flask_menu.py

from collections import OrderedDict
from flask import g


class FlaskMenu(object):
    """Generate menu for flask application.

    Example::
        # create object
        app_menu = FlaskMenu(children=[
            dict(
                menu_id='dashboard',
                title='Dashboard',
                icon='dashboard',
                endpoint='main.index',
                is_visible=lambda menu_instance:True,
            ),
            dict(
                menu_id='order_management',
                title='Order Management',
                icon='list',
                is_visible=lambda menu_instance:True,
                children=[
                    dict(
                        menu_id='order_list',
                        title='Orders',
                        endpoint='orders.index',
                    ),
                    dict(
                        menu_id='order_create',
                        title='Create Order',
                        endpoint='orders.create',
                        is_visible=lambda menu_instance:False,
                    ),
                ],
            ),
        ])
        
        # load jinja utility extension
        app.jinja_env.add_extension('jinja2.ext.do')

        # make this object globally available in template context
        @app.context_processor
        def process_template_context():
            return dict(app_menu=app_menu)

        # render menu in template
        {% for item in app_menu.children recursive %}
            <li {% if item.is_active() or item.has_active_child() %} class="active"{% endif %}>
                {% if item.children %}
                    {% if item.is_visible() and item.has_visible_child() %}
                    <a href="{% if item.endpoint %}{{ url_for(item.endpoint) }}{% else %}javascript:;{% endif %}" data-target="#collapse-{{ item.menu_id }}">
                        {% if item.icon %}<i class="fa fa-fw fa-{{ item.icon }}"></i> {% endif %}{{ item.title }}
                    </a>
                    <ul id="collapse-{{ item.menu_id }}">
                        {{ loop(item.children) }}
                    </ul>
                    {% endif %}
                {% else %}
                    {% if item.is_visible() %}
                    <a href="{% if item.endpoint %}{{ url_for(item.endpoint) }}{% else %}javascript:;{% endif %}"{% if item.is_active() %} class="active"{% endif %}>
                        {% if item.icon %}<i class="fa fa-fw fa-{{ item.icon }}"></i> {% endif %}{{ item.title }}
                    </a>
                    {% endif %}
                {% endif %}
            </li>
        {% endfor %}

        # set active menu in current template outside any block
        {% do app_menu.set_active('order_list') %}
    """
    def __init__(self, menu_id=None, title=None, icon=None, endpoint=None, is_visible=None, children=None):
        self.menu_id = menu_id
        self.title = title
        self.icon = icon
        self.endpoint = endpoint
        self.is_visible_callback = is_visible or (lambda menu_instance:True)
        self.child_entries = OrderedDict()
        if children and isinstance(children, (list, tuple)):
            for child in children:
                if isinstance(child, dict) and child.get('menu_id') and child.get('title'):
                    self.child_entries[child.get('menu_id')] = self.__class__(
                        menu_id=child.get('menu_id'),
                        title=child.get('title'),
                        icon=child.get('icon'),
                        endpoint=child.get('endpoint'),
                        is_visible=child.get('is_visible'),
                        children=child.get('children'),
                    )

    @property
    def children(self):
        return self.child_entries.values()

    @staticmethod
    def set_active(menu_id):
        setattr(g, 'menu_id', menu_id)

    @staticmethod
    def get_active():
        return getattr(g, 'menu_id', None)

    def is_active(self):
        return self.menu_id == self.get_active()

    def has_active_child(self, recursive=True):
        for child in self.child_entries.values():
            if child.is_active():
                return True
        if recursive:
            for child in self.child_entries.values():
                if child.has_active_child(recursive=recursive):
                    return True
        return False

    def is_visible(self):
        return self.is_visible_callback(self)

    def has_visible_child(self, recursive=True):
        for child in self.child_entries.values():
            if child.is_visible():
                return True
        if recursive:
            for child in self.child_entries.values():
                if child.has_visible_child(recursive=recursive):
                    return True
        return False

usage_example_setup.py

from flask_menu import FlaskMenu
import check_menu # any function which returns boolean to set menu visibility of particular menu item


# create object
app_menu = FlaskMenu(children=[
    dict(
        menu_id='dashboard',
        title='Dashboard',
        icon='dashboard',
        endpoint='main.index',
        is_visible=lambda menu_instance:check_menu(menu_instance),
    ),
    dict(
        menu_id='order_management',
        title='Order Management',
        icon='list',
        is_visible=lambda menu_instance:check_menu(menu_instance),
        children=[
            dict(
                menu_id='order_list',
                title='Orders',
                endpoint='orders.index',
            ),
            dict(
                menu_id='order_create',
                title='Create Order',
                endpoint='orders.create',
                is_visible=lambda menu_instance:check_menu(menu_instance),
            ),
        ],
    ),
])

# load jinja utility extension
app.jinja_env.add_extension('jinja2.ext.do')

# make this object globally available in template context
@app.context_processor
def process_template_context():
    return dict(app_menu=app_menu)

usage_example_template.html

<!-- render menu in template -->
{% for item in app_menu.children recursive %}
    <li {% if item.is_active() or item.has_active_child() %} class="active"{% endif %}>
        {% if item.children %}
            {% if item.is_visible() and item.has_visible_child() %}
            <a href="{% if item.endpoint %}{{ url_for(item.endpoint) }}{% else %}javascript:;{% endif %}" data-target="#collapse-{{ item.menu_id }}">
                {% if item.icon %}<i class="fa fa-fw fa-{{ item.icon }}"></i> {% endif %}{{ item.title }}
            </a>
            <ul id="collapse-{{ item.menu_id }}">
                {{ loop(item.children) }}
            </ul>
            {% endif %}
        {% else %}
            {% if item.is_visible() %}
            <a href="{% if item.endpoint %}{{ url_for(item.endpoint) }}{% else %}javascript:;{% endif %}"{% if item.is_active() %} class="active"{% endif %}>
                {% if item.icon %}<i class="fa fa-fw fa-{{ item.icon }}"></i> {% endif %}{{ item.title }}
            </a>
            {% endif %}
        {% endif %}
    </li>
{% endfor %}

<!-- set active menu in current template outside any block -->
{% do app_menu.set_active('order_list') %}