flask-admin-modelview-custom-validation

from flask import Flask
import peewee
from flask.ext import admin
from flask.ext.admin.contrib.peewee import ModelView

app = Flask(__name__)
app.config['SECRET_KEY'] = '123456790'
db = peewee.SqliteDatabase('test.sqlite', check_same_thread=False)

class BaseModel(peewee.Model):
    class Meta:
        database = db

class User(BaseModel):
    username = peewee.CharField(max_length=80, unique=True, null = False)
    email = peewee.CharField(max_length=120)
    def __unicode__(self):
        return self.username

class UserInfo(BaseModel):
    key = peewee.CharField(max_length=64)
    value = peewee.CharField(max_length=64)
    user = peewee.ForeignKeyField(User)
    def __unicode__(self):
        return '%s - %s' % (self.key, self.value)

class Post(BaseModel):
    title = peewee.CharField(max_length=120)
    text = peewee.TextField(null=False)
    date = peewee.DateTimeField()
    user = peewee.ForeignKeyField(User)
    def __unicode__(self):
        return self.title

from wtforms.validators import ValidationError
class UserAdmin(ModelView):
    def no_root_allowed(form, field):
        if field.data == 'root':
            raise ValidationError('"root" is not allowed')

    inline_models = (UserInfo,)
    form_args = dict(
        username=dict(validators=[no_root_allowed])
    )

    def on_model_change(self, form, model, is_created):
        return super(UserAdmin, self).on_model_change(form, model, is_created)

    def update_model(self, form, model):
        return super(UserAdmin, self).update_model(form, model)

    def create_model(self, form):
        return super(UserAdmin, self).create_model(form)

    def delete_model(self, model):
        return super(UserAdmin, self).delete_model(model)

    pass

class PostAdmin(ModelView):
    column_exclude_list = ['text']
    column_sortable_list = ('title', ('user', User.email), 'date')
    column_searchable_list = ('title', User.username)
    column_filters = ('title', 'date', User.email)
    form_ajax_refs = { 'user': { 'fields': (User.username, 'email') } }

@app.route('/')
def index():
    return '<a href="/admin/">Click me to get to Admin!</a>'


if __name__ == '__main__':
    import logging
    logging.basicConfig()
    logging.getLogger().setLevel(logging.DEBUG)

    admin = admin.Admin(app, 'Peewee Models')

    admin.add_view(UserAdmin(User))
    admin.add_view(PostAdmin(Post))

    try:
        User.create_table()
        UserInfo.create_table()
        Post.create_table()
    except:
        pass

    app.run(debug=True)