enterprise-kb-rag/2.2_LangChain基础知识/12_output_parser_str.py

from pathlib import Path
import sys

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

from _chapter2_config import as_text, get_chat_model, print_dependency_hint


try:
    from langchain_core.output_parsers import StrOutputParser
    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)

    prompt = ChatPromptTemplate.from_template("解释{topic}是什么？回答控制20字以内")

    chain1 = prompt | model
    result1 = chain1.invoke({"topic": "ai"})
    print(f"result1-->{as_text(result1)}")

    parser = StrOutputParser()
    chain2 = prompt | model | parser
    result2 = chain2.invoke({"topic": "ai"})
    print(f"result2-->{result2}")


if __name__ == "__main__":
    main()