langchain1.x学习笔记（三）：langchain之init_chat_model的新用法

在langchain1.x中，使用init_chat_model函数进行构建model。

1. 第一种方式：支持硅基流动的调用

fromenvs.envsimportOPENAI_BASE_URL,OPENAI_BASE_MODEL,OPENAI_API_KEYfromlangchain.chat_modelsimportinit_chat_model model=init_chat_model(model_provider="openai",model=OPENAI_BASE_MODEL,api_key=OPENAI_API_KEY,base_url=OPENAI_BASE_URL,temperature=0,)response=model.invoke(input="hello")print(response)

2. 第二种方式：后配置

fromenvs.envsimportOPENAI_BASE_URL,OPENAI_BASE_MODEL,OPENAI_API_KEYfromlangchain.chat_modelsimportinit_chat_model model=init_chat_model(temperature=0,)response=model.invoke(input="hello",config={"model_provider":"openai","model":OPENAI_BASE_MODEL,"api_key":OPENAI_API_KEY,"base_url":OPENAI_BASE_URL,"max_tokens":4096,},)print(response)

3. 第三种：流式输出

fromenvs.envsimportOPENAI_BASE_URL,OPENAI_BASE_MODEL,OPENAI_API_KEYfromlangchain.chat_modelsimportinit_chat_model model=init_chat_model(temperature=0,)stream=model.stream(input="hello",config={"model_provider":"openai","model":OPENAI_BASE_MODEL,"api_key":OPENAI_API_KEY,"base_url":OPENAI_BASE_URL,"max_tokens":4096,},)forchunkinstream:print(chunk.content,end="",flush=True)

4. 第四种：异步流式输出

fromenvs.envsimportOPENAI_BASE_URL,OPENAI_BASE_MODEL,OPENAI_API_KEYfromlangchain.chat_modelsimportinit_chat_modelimportasyncioasyncdefasync_stream():model=init_chat_model(temperature=0,)stream=model.astream(input="hello",config={"model_provider":"openai","model":OPENAI_BASE_MODEL,"api_key":OPENAI_API_KEY,"base_url":OPENAI_BASE_URL,"max_tokens":4096,},)asyncforchunkinstream:print(chunk.content,end="",flush=True)if__name__=="__main__":asyncio.run(async_stream())

5. 提示词模板结合管道进行使用

fromenvs.envsimportOPENAI_BASE_URL,OPENAI_BASE_MODEL,OPENAI_API_KEYfromlangchain.chat_modelsimportinit_chat_modelfromlangchain_core.promptsimportChatPromptTemplatefromlangchain_core.output_parsersimportStrOutputParser prompt=ChatPromptTemplate.from_messages([("system","You are a helpful assistant."),("human","{question}"),])model=init_chat_model(model_provider="openai",model=OPENAI_BASE_MODEL,api_key=OPENAI_API_KEY,base_url=OPENAI_BASE_URL,)chain=prompt|model|StrOutputParser()result=chain.invoke({"question":"你是谁?"})print(result)