backend/custom_components.py

from typing import Dict, List

from haystack import component

import json
import json_repair

@component
class QuizParser:
    @component.output_types(quiz=Dict)
    def run(self, replies: List[str]):
        reply = replies[0]

        # even if prompted to respond with JSON only, sometimes the model returns a mix of JSON and text
        first_index = min(reply.find("{"), reply.find("["))
        last_index = max(reply.rfind("}"), reply.rfind("]")) + 1

        json_portion = reply[first_index:last_index]

        try:
            quiz = json.loads(json_portion)
        except json.JSONDecodeError:
            # if the JSON is not well-formed, try to repair it
            quiz = json_repair.loads(json_portion)

        # sometimes the JSON contains a list instead of a dictionary
        if isinstance(quiz, list):
            quiz = quiz[0]

        print(quiz)

        return {"quiz": quiz}