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import streamlit as st | |
from PyPDF2 import PdfReader | |
from langchain.text_splitter import RecursiveCharacterTextSplitter | |
import os | |
from langchain_google_genai import GoogleGenerativeAIEmbeddings | |
from langchain_community.vectorstores import FAISS | |
from langchain_google_genai import ChatGoogleGenerativeAI | |
from langchain.chains.question_answering import load_qa_chain | |
from langchain.prompts import PromptTemplate | |
#from dotenv import load_dotenv | |
#load_dotenv() | |
API_KEYS = [os.getenv("APIKEY1"), os.getenv("APIKEY2")] | |
current_key_index = -1 | |
def switch_api_key(): | |
global current_key_index | |
current_key_index = (current_key_index + 1) % len(API_KEYS) | |
return API_KEYS[current_key_index] | |
def get_pdf_text(pdf_docs): | |
text = "" | |
for pdf in pdf_docs: | |
pdf_reader = PdfReader(pdf) | |
for page in pdf_reader.pages: | |
text += page.extract_text() | |
return text | |
def get_text_chunks(text): | |
text_splitter = RecursiveCharacterTextSplitter(chunk_size=10000, chunk_overlap=1000) | |
return text_splitter.split_text(text) | |
def get_vector_store(text_chunks): | |
api_key = switch_api_key() | |
embeddings = GoogleGenerativeAIEmbeddings(model="models/embedding-001", google_api_key=api_key) | |
vector_store = FAISS.from_texts(text_chunks, embedding=embeddings) | |
vector_store.save_local("faiss_index") | |
def get_conversational_chain(): | |
api_key = switch_api_key() | |
prompt_template = """ | |
You are a helpful assistant that only answers based on the context provided from the PDF documents. | |
Do not use any external knowledge or assumptions. If the answer is not found in the context below, reply with "I don't know." | |
Context: | |
{context} | |
Question: | |
{question} | |
Answer: | |
""" | |
model = ChatGoogleGenerativeAI(model="gemini-2.0-flash", temperature=0, google_api_key=api_key) | |
prompt = PromptTemplate(template=prompt_template, input_variables=["context", "question"]) | |
chain = load_qa_chain(model, chain_type="stuff", prompt=prompt) | |
return chain | |
def user_input(user_question): | |
api_key = switch_api_key() | |
embeddings = GoogleGenerativeAIEmbeddings(model="models/embedding-001", google_api_key=api_key) | |
new_db = FAISS.load_local("faiss_index", embeddings, allow_dangerous_deserialization=True) | |
docs = new_db.similarity_search(user_question) | |
chain = get_conversational_chain() | |
response = chain({"input_documents": docs, "question": user_question}, return_only_outputs=True) | |
st.write("Reply: ", response["output_text"]) | |
# Streamlit application | |
def main(): | |
st.set_page_config("Chat PDF") | |
st.header("CSC 121: Computers and Scientific Thinking (Chatbot)") | |
st.subheader("Ask a question ONLY from the CSC 121 textbook of Dr. Reed",divider=True) | |
user_question = st.text_input("Ask a question") | |
if user_question: | |
user_input(user_question) | |
pdf_docs = st.file_uploader("Upload PDF files", accept_multiple_files=True) | |
if st.button("Submit & Process"): | |
with st.spinner("Processing..."): | |
raw_text = get_pdf_text(pdf_docs) | |
text_chunks = get_text_chunks(raw_text) | |
get_vector_store(text_chunks) | |
st.success("Done") | |
if __name__ == "__main__": | |
main() | |