flask-admin: how to allow only super users can view the specified table column?

Question

I've built an app with a table called Project which is stored in sqlite, I want allow only super users can view the approve column when creating, editing data.

The Project data is retrieved in the "class Project", and I've added if current_user.has_role('superuser') in "class ProjectView":

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_security import SQLAlchemyUserDatastore, current_user,UserMixin,        
     RoleMixin
from flask_admin.contrib import sqla

 # Create Flask application
 app = Flask(__name__)
 app.config.from_pyfile('config.py')
 db = SQLAlchemy(app)

 # Define models
 roles_users = db.Table(
     'roles_users',
     db.Column('user_id', db.Integer(), db.ForeignKey('user.id')),
     db.Column('role_id', db.Integer(), db.ForeignKey('role.id'))
 )

 class Role(db.Model, RoleMixin):
     id = db.Column(db.Integer(), primary_key=True)
     name = db.Column(db.String(80), unique=True)
     description = db.Column(db.String(255))

     def __str__(self):
         return self.name

 class User(db.Model, UserMixin):
     id = db.Column(db.Integer, primary_key=True)
     email = db.Column(db.String(255), unique=True)
     password = db.Column(db.String(255))
     roles = db.relationship('Role', secondary=roles_users,
                        backref=db.backref('users', lazy='dynamic'))

     def __str__(self):
         return self.email

 class Project(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    team = db.Column(db.Unicode(64))
    project_name = db.Column(db.Unicode(128))
    approve = db.Column(db.Boolean())

 # Setup Flask-Security
 user_datastore = SQLAlchemyUserDatastore(db, User, Role)
 security = Security(app, user_datastore)


  # Create customized model view class
 class MyModelView(sqla.ModelView):

     def is_accessible(self):
        if not current_user.is_active or not current_user.is_authenticated:
            return False

        if current_user.has_role('superuser'):
            return True

        return False

     def _handle_view(self, name, **kwargs):
        if not self.is_accessible():
            if current_user.is_authenticated:
                # permission denied
               abort(403)
        else:
            # login
            return redirect(url_for('security.login', next=request.url))

 class ProjectView(sqla.ModelView):

    def is_accessible(self):
        if not current_user.is_active:
            return False
        else:
            return True

    def _handle_view(self, name, **kwargs):
        if not self.is_accessible():
            if current_user.is_authenticated:
                # permission denied
               abort(403)
            else:
               if current_user.has_role('superuser'):
                 form_create_rules = [
                 rules.FieldSet(('team'), 'Personal Info'),
                 rules.Header('Project Info'),
                 rules.Field('project_name'),
                 'approve',
                 rules.Container('rule_demo.wrap', rules.Field('notes'))
                 ]

             else: 
                 form_create_rules = [
                 rules.FieldSet(('team'), 'Personal Info'),
                 rules.Header('Project Info'),
                 rules.Field('project_name'),
                 #'approve',
                 rules.Container('rule_demo.wrap', rules.Field('notes'))
                 ]
             form_edit_rules = form_create_rules

             create_template = 'rule_create.html'
             edit_template = 'rule_edit.html'

    @app.route('/')
    def index():
      return render_template('index.html')

    # Create admin
    admin = flask_admin.Admin(
          app,
          'Release Control System',
          # log in success page
          base_template='my_master.html',   
          template_mode='bootstrap3',
        )

   # Add model views
   admin.add_view(MyModelView(Role, db.session))
   admin.add_view(MyModelView(User, db.session))
   admin.add_view(ProjectView(Project, db.session))

But it still not works and all users still can view the approve column. Kindly advise. Thanks in advance.

Answer 1

You can use BaseModelView.column_list attribute to specify dynamically calculated list of accessible columns, just make it a property. However different "field" attributes of ModelView are cached on application launch so you need to override their caches:

from flask import has_app_context

class ProjectView(sqla.ModelView):
    @property
    def _list_columns(self):
        return self.get_list_columns()

    @_list_columns.setter
    def _list_columns(self, value):
        pass

    @property
    def column_list(self):
        if not has_app_context() or current_user.has_role('superuser'):
            return ['team', 'project_name', 'approve']
        else:
            return ['team', 'project_name']

column_list attribute is used during application initialisation when current_user is not available. Use flask.has_app_context() method to check this state and pass application a full list of columns on launch.

If you need to specify different set of columns for editing you need form_rules attributes (you already used them in your question):

from flask_admin.form import rules

class ProjectView(sqla.ModelView):
    @property
    def _form_edit_rules(self):
        return rules.RuleSet(self, self.form_rules)

    @_form_edit_rules.setter
    def _form_edit_rules(self, value):
        pass

    @property
    def _form_create_rules(self):
        return rules.RuleSet(self, self.form_rules)

    @_form_create_rules.setter
    def _form_create_rules(self, value):
        pass

    @property
    def form_rules(self):
        form_rules = [
            rules.FieldSet(('team',), 'Personal Info'),
            rules.Header('Project Info'),
            rules.Field('project_name')
        ]
        if not has_app_context() or current_user.has_role('superuser'):
            form_rules.append('approve')
        form_rules.append(rules.Container('rule_demo.wrap', rules.Field('notes')))
        return form_rules

Also you do not need to use _handle_view to redirect user to login page. For this purpose BaseView.inaccessible_callback method is used:

def inaccessible_callback(self, name, **kwargs):
    if current_user.is_authenticated:
        abort(403)
    else:
        return redirect(url_for('security.login', next=request.url))