LangChain 013

from langchain.chains import load_chain

chain = load_chain("lc://chains/hello-world/chain.json")

chain.run("男人")

from typing import List, Dict, Any, Optional
from langchain.callbacks.manager import (
    CallbackManagerForChainRun
)
from langchain.chains.base import  Chain
from langchain.prompts.base import BasePromptTemplate
from langchain.base_language import  BaseLanguageModel

class wiki_article_chain(Chain):
    """开发一个wiki文章生成器"""
    prompt:BasePromptTemplate
    llm:BaseLanguageModel
    out_key:str="text"

    @property
    def input_keys(self) -> List[str]:
        """将返回Prompt所需的所有键"""
        return self.prompt.input_variables
    
    @property
    def output_keys(self) -> List[str]:
        """将始终返回text键"""
        return [self.out_key]
    
    def _call(
        self,
        inputs:Dict[str,Any],
        run_manager:Optional[CallbackManagerForChainRun]=None,
    ) -> Dict[str,Any]:
        """运行链"""
        prompt_value = self.prompt.format_prompt(**inputs)
        #print("prompt_value:",prompt_value)
        response = self.llm.generate_prompt(
            [prompt_value],callbacks=run_manager.get_child() if run_manager else None
        )
        #print("response:",response)
        if run_manager:
            run_manager.on_text("wiki article is written")
        return {self.out_key:response.generations[0][0].text}
    
    @property
    def _chain_type(self) -> str:
        """链类型"""
        return "wiki_article_chain"
       

from langchain.chat_models import  ChatOpenAI
from langchain.prompts import  PromptTemplate

chain = wiki_article_chain(
    prompt=PromptTemplate(
        template="写一篇关于{topic}的维基百科形式的文章",
        input_variables=["topic"]
    ),
    llm=ChatOpenAI(
        temperature=0
    ),
)

result = chain.run({"topic":"降本增效"})
print(result)