Module: retriever_util

# Copyright (C) 2023-present The Project Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import json
import re
from typing import Optional


class RetrieverUtil:
    """Helper methods for retrievers."""

    @classmethod
    def extract_json(cls, text: str) -> Optional[dict]:
        """Extract JSON from model output."""
        match = re.search(r"({.*})", text, re.DOTALL)
        if match is None:
            return None
        json_string = match.group(1)
        try:
            return json.loads(json_string)
        except json.JSONDecodeError:
            return None