Flask-Admin and Blueprint factory pattern is giving werkzeug.routing.BuildError: Could not build url for endpoint 'admin.static'

Question

In Flask-Admin Blueprint factory pattern, I'm getting following error when I try to visit http://127.0.0.1:5000/users/ here is given the complete stack trace of the application when I try to open the endpoint in browser

  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/base.py", line 308, in render
    return render_template(template, **kwargs)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/templating.py", line 135, in render_template
    context, ctx.app)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/templating.py", line 117, in _render
    rv = template.render(context)
  File "/home/maverick/.local/lib/python3.5/site-packages/jinja2/environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "/home/maverick/.local/lib/python3.5/site-packages/jinja2/environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/maverick/.local/lib/python3.5/site-packages/jinja2/_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/templates/bootstrap3/admin/model/list.html", line 6, in top-level template code
    {% import 'admin/model/row_actions.html' as row_actions with context %}
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/templates/bootstrap3/admin/master.html", line 1, in top-level template code
    {% extends admin_base_template %}
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/templates/bootstrap3/admin/base.html", line 14, in top-level template code
    {% block head_css %}
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/templates/bootstrap3/admin/base.html", line 15, in block "head_css"
    <link href="{{ admin_static.url(filename='bootstrap/bootstrap3/swatch/{swatch}/bootstrap.min.css'.format(swatch=config.get('FLASK_ADMIN_SWATCH', 'default')), v='3.3.5') }}" rel="stylesheet">
  File "/home/maverick/.local/lib/python3.5/site-packages/jinja2/runtime.py", line 579, in _invoke
    rv = self._func(*arguments)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/templates/bootstrap3/admin/static.html", line 2, in template
    {{ get_url('admin.static', *varargs, **kwargs) }}
  File "/home/maverick/.local/lib/python3.5/site-packages/flask_admin/base.py", line 390, in get_url
    return url_for(endpoint, **kwargs)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/helpers.py", line 356, in url_for
    return appctx.app.handle_url_build_error(error, endpoint, values)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/app.py", line 2061, in handle_url_build_error
    reraise(exc_type, exc_value, tb)
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/maverick/.local/lib/python3.5/site-packages/flask/helpers.py", line 345, in url_for
    force_external=external)
  File "/home/maverick/.local/lib/python3.5/site-packages/werkzeug/routing.py", line 2181, in build
    raise BuildError(endpoint, values, method, self)
werkzeug.routing.BuildError: Could not build url for endpoint 'admin.static' with values ['filename', 'v']. Did you mean 'static' instead?

app/__init__.py

def create_app(config_class=Config):
    app = Flask(__name__)
    app.config.from_object(config_class)
    # extension initiation
    [...]
    # factory registration
    [...]

    from app.admin.core import MicroModelView # subclass of ModelView
    from app.models import User # db table

    f_admin = Admin(
        app,
        name='new admin',
        index_view=MicroModelView(User, db.session, endpoint='users', url='/users'),
        template_mode='bootstrap3',

    )

app/admin/core.py:

class MicroModelView(ModelView):
    page_size = 5

What is the problem, and how can it be resolved?

Answer 1

The error is caused by you setting index_view to a ModelView subclass. Don't do that.

Normally, index_view is set to an instance of the AdminIndexView() class , and it is this class that registers an admin.static view to handle static files used in the admin UI (the Javascript and CSS files used in the templates).

But a ModelView subclass does not provide those. You need to register those with admin.add_view() calls instead:

f_admin = Admin(
    app,
    name='new admin',
    template_mode='bootstrap3',
)
f_admin.add_view(MicroModelView(User, db.session, endpoint='users', url='/users'))

If you want to change the default /admin/ page behaviour, you'd need to subclass the AdminIndexView class and override its index method; you could redirect to the users view, for instance:

# additional imports
from flask import redirect
from flask_admin import AdminIndexView, expose

class MicroModelAdminIndexView(AdminIndexView):
    @expose
    def index(self):
        return redirect('users.index')


f_admin = Admin(
    app,
    name='new admin',
    template_mode='bootstrap3',
    index_view=MicroModelAdminIndexView()
)
f_admin.add_view(MicroModelView(User, db.session, endpoint='users', url='/users'))