enterprise-kb-rag/2.2_LangChain基础知识/14_output_parser_json.py

from pathlib import Path
import sys

sys.path.append(str(Path(__file__).resolve().parents[1]))

from _chapter2_config import get_chat_model, print_dependency_hint


try:
    from langchain_core.output_parsers import JsonOutputParser
    from langchain_core.prompts import ChatPromptTemplate
except ModuleNotFoundError as exc:
    print_dependency_hint(exc)
    raise SystemExit(1)


def main() -> None:
    try:
        model = get_chat_model(temperature=0)
    except ModuleNotFoundError as exc:
        print_dependency_hint(exc)
        raise SystemExit(1)

    json_parser = JsonOutputParser()
    json_format_instructions = json_parser.get_format_instructions()
    json_prompt = ChatPromptTemplate.from_template(
        "生成一个包含{person}基本信息的JSON。应包括姓名、职业、年龄和技能列表，不要包含任何注释或额外说明。\n{format_instructions}"
    )

    json_chain = json_prompt | model | json_parser
    result = json_chain.invoke(
        {
            "person": "雷军",
            "format_instructions": json_format_instructions,
        }
    )
    print(result)


if __name__ == "__main__":
    main()