【基于langchain + streamlit 完整的与文档对话RAG】

本地部署文档问答webdemo

支持 pdf
支持 txt
支持 doc/docx
支持 源文档索引

你的点赞和收藏是我持续分享优质内容的动力哦~

废话不多说直接看效果

在这里插入图片描述

准备

首先创建一个新环境（选择性）

conda create -n chatwithdocs python=3.11
conda activate chatwithdocs

新建一个requirements.txt文件

streamlit
python-docx
PyPDF2
faiss-gpu
langchain
langchain-core
langchain-community

然后安装相应的包

pip install -r requirements.txt -U

代码

创建一个app.py文件，把下边的复制进去
注意：替换你自己的api-key和base-url

import streamlit as st
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import FAISS
from langchain_openai import ChatOpenAI
from langchain_openai import OpenAIEmbeddings
from langchain_core.documents import Document
from langchain.chains import ConversationalRetrievalChain
import docx
from PyPDF2 import PdfReaderimport os
os.environ['OPENAI_API_KEY']='xxx'
# os.environ['OPENAI_BASE_URL']='xxx' # 看你的情况st.set_page_config(page_title="Chat with Documents", page_icon=":robot:", layout="wide")st.markdown("""<style>
.chat-message {padding: 1.5rem; border-radius: 0.5rem; margin-bottom: 1rem; display: flex
}
.chat-message.user {background-color: #2b313e
}
.chat-message.bot {background-color: #475063
}
.chat-message .avatar {width: 20%;
}
.chat-message .avatar img {max-width: 78px;max-height: 78px;border-radius: 50%;object-fit: cover;
}
.chat-message .message {width: 80%;padding: 0 1.5rem;color: #fff;
}
.stDeployButton {visibility: hidden;}
#MainMenu {visibility: hidden;}
footer {visibility: hidden;}.block-container {padding: 2rem 4rem 2rem 4rem;
}.st-emotion-cache-16txtl3 {padding: 3rem 1.5rem;
}
</style>
# """,unsafe_allow_html=True,
)bot_template = """
<div class="chat-message bot"><div class="avatar"><img src="https://cdn.icon-icons.com/icons2/1371/PNG/512/robot02_90810.png" style="max-height: 78px; max-width: 78px; border-radius: 50%; object-fit: cover;"></div><div class="message">{{MSG}}</div>
</div>
"""user_template = """
<div class="chat-message user"><div class="avatar"><img src="https://www.shareicon.net/data/512x512/2015/09/18/103160_man_512x512.png" ></div>    <div class="message">{{MSG}}</div>
</div>
"""def get_pdf_text(pdf_docs):docs = []for document in pdf_docs:if document.type == "application/pdf":pdf_reader = PdfReader(document)for idx, page in enumerate(pdf_reader.pages):docs.append(Document(page_content=page.extract_text(),metadata={"source": f"{document.name} on page {idx}"},))elif (document.type== "application/vnd.openxmlformats-officedocument.wordprocessingml.document"):doc = docx.Document(document)for idx, paragraph in enumerate(doc.paragraphs):docs.append(Document(page_content=paragraph.text,metadata={"source": f"{document.name} in paragraph {idx}"},))elif document.type == "text/plain":text = document.getvalue().decode("utf-8")docs.append(Document(page_content=text, metadata={"source": document.name}))return docsdef get_text_chunks(docs):text_splitter = RecursiveCharacterTextSplitter(chunk_size=512, chunk_overlap=0)docs_chunks = text_splitter.split_documents(docs)return docs_chunksdef get_vectorstore(docs_chunks):embeddings = OpenAIEmbeddings()vectorstore = FAISS.from_documents(docs_chunks, embedding=embeddings)return vectorstoredef get_conversation_chain(vectorstore):llm = ChatOpenAI()conversation_chain = ConversationalRetrievalChain.from_llm(llm=llm,retriever=vectorstore.as_retriever(),return_source_documents=True,)return conversation_chaindef handle_userinput_pdf(user_question):chat_history = st.session_state.chat_historyresponse = st.session_state.conversation({"question": user_question, "chat_history": chat_history})st.session_state.chat_history.append(("user", user_question))st.session_state.chat_history.append(("assistant", response["answer"]))st.write(user_template.replace("{{MSG}}", user_question),unsafe_allow_html=True,)sources = response["source_documents"]source_names = set([i.metadata["source"] for i in sources])src = "\n\n".join(source_names)src = f"\n\n> source : {src}"message = st.session_state.chat_history[-1]st.write(bot_template.replace("{{MSG}}", message[1] + src), unsafe_allow_html=True)def show_history():chat_history = st.session_state.chat_historyfor i, message in enumerate(chat_history):if i % 2 == 0:st.write(user_template.replace("{{MSG}}", message[1]),unsafe_allow_html=True,)else:st.write(bot_template.replace("{{MSG}}", message[1]), unsafe_allow_html=True)def main():st.header("Chat with Documents")# 初始化会话状态if "conversation" not in st.session_state:st.session_state.conversation = Noneif "chat_history" not in st.session_state:st.session_state.chat_history = []with st.sidebar:st.title("文档管理")pdf_docs = st.file_uploader("选择文件",type=["pdf", "txt", "doc", "docx"],accept_multiple_files=True,)if st.button("处理文档",on_click=lambda: setattr(st.session_state, "last_action", "pdf"),use_container_width=True,):if pdf_docs:with st.spinner("Processing"):docs = get_pdf_text(pdf_docs)docs_chunks = get_text_chunks(docs)vectorstore = get_vectorstore(docs_chunks)st.session_state.conversation = get_conversation_chain(vectorstore)else:st.warning("记得上传文件哦~~")def clear_history():st.session_state.chat_history = []if st.session_state.chat_history:st.button("清空对话", on_click=clear_history, use_container_width=True)with st.container():user_question = st.chat_input("输入点什么~")with st.container(height=400):show_history()if user_question:if st.session_state.conversation is not None:handle_userinput_pdf(user_question)else:st.warning("记得上传文件哦~~")if __name__ == "__main__":main()