Langchain-Chatchat/chains/local_doc_qa.py

117 lines
4.5 KiB
Python

from langchain.chains import RetrievalQA
from langchain.prompts import PromptTemplate
from langchain.embeddings.huggingface import HuggingFaceEmbeddings
from langchain.vectorstores import FAISS
from langchain.document_loaders import UnstructuredFileLoader
from models.chatglm_llm import ChatGLM
import sentence_transformers
import os
from configs.model_config import *
import datetime
from typing import List
# return top-k text chunk from vector store
VECTOR_SEARCH_TOP_K = 10
# LLM input history length
LLM_HISTORY_LEN = 3
# Show reply with source text from input document
REPLY_WITH_SOURCE = True
class LocalDocQA:
llm: object = None
embeddings: object = None
def init_cfg(self,
embedding_model: str = EMBEDDING_MODEL,
embedding_device=EMBEDDING_DEVICE,
llm_history_len: int = LLM_HISTORY_LEN,
llm_model: str = LLM_MODEL,
llm_device=LLM_DEVICE,
top_k=VECTOR_SEARCH_TOP_K,
):
self.llm = ChatGLM()
self.llm.load_model(model_name_or_path=llm_model_dict[llm_model],
llm_device=llm_device)
self.llm.history_len = llm_history_len
self.embeddings = HuggingFaceEmbeddings(model_name=embedding_model_dict[embedding_model], )
self.embeddings.client = sentence_transformers.SentenceTransformer(self.embeddings.model_name,
device=embedding_device)
self.top_k = top_k
def init_knowledge_vector_store(self,
filepath: str or List[str]):
if isinstance(filepath, str):
if not os.path.exists(filepath):
print("路径不存在")
return None
elif os.path.isfile(filepath):
file = os.path.split(filepath)[-1]
try:
loader = UnstructuredFileLoader(filepath, mode="elements")
docs = loader.load()
print(f"{file} 已成功加载")
except:
print(f"{file} 未能成功加载")
return None
elif os.path.isdir(filepath):
docs = []
for file in os.listdir(filepath):
fullfilepath = os.path.join(filepath, file)
try:
loader = UnstructuredFileLoader(fullfilepath, mode="elements")
docs += loader.load()
print(f"{file} 已成功加载")
except:
print(f"{file} 未能成功加载")
else:
docs = []
for file in filepath:
try:
loader = UnstructuredFileLoader(file, mode="elements")
docs += loader.load()
print(f"{file} 已成功加载")
except:
print(f"{file} 未能成功加载")
vector_store = FAISS.from_documents(docs, self.embeddings)
vs_path = f"""./vector_store/{os.path.splitext(file)[0]}_FAISS_{datetime.datetime.now().strftime("%Y%m%d_%H%M%S")}"""
vector_store.save_local(vs_path)
return vs_path if len(docs)>0 else None
def get_knowledge_based_answer(self,
query,
vs_path,
chat_history=[], ):
prompt_template = """基于以下已知信息,简洁和专业的来回答用户的问题。
如果无法从中得到答案,请说 "根据已知信息无法回答该问题""没有提供足够的相关信息",不允许在答案中添加编造成分,答案请使用中文。
已知内容:
{context}
问题:
{question}"""
prompt = PromptTemplate(
template=prompt_template,
input_variables=["context", "question"]
)
self.llm.history = chat_history
vector_store = FAISS.load_local(vs_path, self.embeddings)
knowledge_chain = RetrievalQA.from_llm(
llm=self.llm,
retriever=vector_store.as_retriever(search_kwargs={"k": self.top_k}),
prompt=prompt
)
knowledge_chain.combine_documents_chain.document_prompt = PromptTemplate(
input_variables=["page_content"], template="{page_content}"
)
knowledge_chain.return_source_documents = True
result = knowledge_chain({"query": query})
self.llm.history[-1][0] = query
return result, self.llm.history