Complex Flask-Admin View with custom filters and bulk action

example.py

class FilterLowercase(BaseMongoEngineFilter):
    def apply(self, query, value):
        flt = {'%s__icontains' % self.column: value}
        return query.filter(**flt)

    def operation(self):
        return gettext('contains')

class FilterLowercaseNot(BaseMongoEngineFilter):
    def apply(self, query, value):
        flt = {'%s__not__icontains' % self.column: value}
        return query.filter(**flt)

    def operation(self):
        return gettext('doesn\'t contain')

class FilterArtistsSimilar(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(similar__in=models.Artist.objects(name__icontains=value))

	def operation(self):
		return gettext('contains')

class FilterArtistsNotSimilar(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(similar__nin=models.Artist.objects(name__icontains=value))

	def operation(self):
		return gettext('doesn\'t contain')

class FilterTags(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(tags__in=models.Tag.objects(name__icontains=value))

	def operation(self):
		return gettext('contains')

class FilterTagsNot(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(tags__nin=models.Tag.objects(name__icontains=value))

	def operation(self):
		return gettext('doesn\'t contain')
	
class FilterTagsSimilar(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(similar__in=models.Tag.objects(name__icontains=value))

	def operation(self):
		return gettext('contains')

class FilterTagsNotSimilar(BaseMongoEngineFilter):
	def apply(self, query, value):
		return query.filter(similar__nin=models.Tag.objects(name__icontains=value))

	def operation(self):
		return gettext('doesn\'t contain')

class FilterArtistsFollowed(BooleanEqualFilter):
	def apply(self, query, value):
		if value == '1':
			return models.Artist.followed()
		else:
			return models.Artist.unfollowed()

	def operation(self):
		return gettext('followed')

class ArtistView(ModelView):
	column_searchable_list = ('name', 'youtube_user', 'soundcloud_user', 'twitter_user', 'musicbrainz_id', 'facebook_user')
	column_list = ('name', 'youtube_user', 'soundcloud_user', 'twitter_user', 'facebook_user', 'discogs_id', 'musicbrainz_id', 'created_on', 'updated_on', 'image', 'active')
	form_excluded_columns = ('created_on', 'updated_on', 'image')
	allowed_search_types = (StringField, models.LowerStringField)
	column_filters = [
			FilterLowercase('name', 'Name'), FilterLowercase('soundcloud_user', 'Soundcloud User'), FilterLowercase('twitter_user', 'Twitter User'), FilterLowercase('youtube_user', 'Youtube User'), FilterLowercase('facebook_user', 'Facebook User'),
			FilterLowercaseNot('name', 'Name'), FilterLowercaseNot('soundcloud_user', 'Soundcloud User'), FilterLowercaseNot('twitter_user', 'Twitter User'), FilterLowercaseNot('youtube_user', 'Youtube User'), FilterLowercaseNot('facebook_user', 'Facebook User'),
			FilterArtistsSimilar('artists', 'Similar Artist Name'),
			FilterArtistsNotSimilar('artists', 'Similar Artist Name'),
			FilterTags('tags', 'Tag Name'),
			FilterTagsNot('tags', 'Tag Name'),
			BooleanEqualFilter(models.Artist.active, 'Is Active?'),
			FilterArtistsFollowed(models.Artist, 'Is Followed?'),
			]
	column_formatters = dict( 
			soundcloud_user = lambda v, c, m, p: m.Markup('<a href="https://soundcloud.com/'+str(m.soundcloud_user)+'">'+str(m.soundcloud_user)+'</a>' if m.soundcloud_user else ''),
			twitter_user = lambda v, c, m, p: m.Markup('<a href="https://twitter.com/'+str(m.twitter_user)+'">'+str(m.twitter_user)+'</a>' if m.twitter_user else ''),
			youtube_user = lambda v, c, m, p: m.Markup('<a href="https://youtube.com/user/'+str(m.youtube_user)+'">'+str(m.youtube_user)+'</a>' if m.youtube_user else ''),
			facebook_user = lambda v, c, m, p: m.Markup('<a href="https://facebook.com/'+str(m.facebook_user)+'">'+str(m.facebook_user)+'</a>' if m.facebook_user else ''),
			name = lambda v, c, m, p: m.Markup('<a href="https://www.google.com/search?q=&quot;'+m.name+'&quot;+music+artist">'+m.name+'</a>'),
			musicbrainz_id = lambda v, c, m, p: m.Markup('<a href="https://www.musicbrainz.org/artist/'+m.musicbrainz_id+'">'+m.musicbrainz_id+'</a>')
			)

	form_ajax_refs = {
			'similar': {
				'fields': ['name'],
				'page_size': 15
				},
			'tags': {
				'fields': ['name'],
				'page_size': 15
				},
			'releases': {
				'fields': ['name'],
				'page_size': 15
				}
			}	

	def is_accessible(self):
		if current_user.is_authenticated():
			return current_user.is_admin

	def scaffold_form(self):
		form_class = super(ArtistView, self).scaffold_form()
		form_class.name            = TextField('Artist Name')
		form_class.soundcloud_user = TextField('SoundCloud Username')
		form_class.youtube_user    = TextField('Youtube Username')
		form_class.facebook_user   = TextField('FacebookUsername')
		form_class.twitter_user    = TextField('Twitter Username')
		form_class.musicbrainz_id  = TextField('Musicbrainz ID')
		return form_class

	@action('toggle',
			lazy_gettext('Toggle'),
			lazy_gettext('Are you sure you want to toggle the selected items?'))
	def action_toggle(self, ids):
		try:
			count = 0

			for id in ids:
				artist = models.Artist.objects.get(pk=id)
				if artist.active:
					artist.active = False
				else:
					artist.active = True
				artist.save()
				count += 1

			flash(ngettext('Item was successfully toggled.',
				'%(count)s items were successfully toggled.',
				count,
				count=count))
		except Exception, ex:
			flash(gettext('Failed to toggle items. %(error)s', error=str(ex)), 'error')