frappe_nested_filters.py

def nested_filters():
	sql_string = parse_nested_filters('Item',
		['and', [
			['has_variant', '=', 1],
			['show_in_website', '=', 0],
			['or', [
				['variant_of', '=', 'test'],
				['item_group', '=', 'product'],
				['and', [
					['item_code', '>', 'hello'],
					['item_code', '<', 'test']
				]]
			]]
		]]
	)

	print(sql_string)

def parse_nested_filters(doctype, nested_filters, operator=None):

	filter_string = ''

	if operator:
		simple_filters = [f for f in nested_filters if len(f) > 2]
		nested_filters = [f for f in nested_filters if len(f) == 2]

		simple_conditions = get_conditions(doctype, simple_filters)
		nested_conditions = [parse_nested_filters(doctype, f) for f in nested_filters]

		filter_string += '(' + (' ' + operator + ' ').join(simple_conditions + nested_conditions) + ')'
		return filter_string

	for val in nested_filters:
		if isinstance(val, frappe.string_types):
			operator = val
		else:
			filter_string = parse_nested_filters(doctype, val, operator)

	return filter_string

def get_conditions(filter_list):
	from frappe.model.db_query import DatabaseQuery

	conditions = []
	DatabaseQuery('Item').build_filter_conditions(filter_list, conditions)

	return conditions