app.py

from flask import Flask, request, jsonify
from langchain_community.document_loaders import TextLoader
from langchain.text_splitter import CharacterTextSplitter
from langchain_community.embeddings import HuggingFaceEmbeddings
from langchain_community.vectorstores import FAISS
from langchain.chains.question_answering import load_qa_chain
from langchain_community.llms.huggingface_endpoint import HuggingFaceEndpoint

# To comment in production usage
# import Constants
import os
# os.environ["HUGGINGFACEHUB_API_TOKEN"] = $(cat /run/secrets/HUGGINGFACEHUB_API_TOKEN)


app = Flask(__name__)


# try:
loader = TextLoader("./data/app.txt")
document = loader.load()

# Split the document into chunks
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(document)

# Create embeddings
embedding = HuggingFaceEmbeddings(model_name = "sentence-transformers/all-mpnet-base-v2")
db = FAISS.from_documents(docs, embedding)

# Load the Question-Answering chain
llm = HuggingFaceEndpoint(repo_id="google/flan-t5-xxl", temperature=0.8, model_kwargs={"max_length": 512})
chain = load_qa_chain(llm, chain_type="stuff")

# except Exception as e:
#     print("Recived Setup error: ", e)

def process_query(query):
    # os.system("cls")

    # try:
    querySimilarDocs = db.similarity_search(query)

    res = chain.run(input_documents = querySimilarDocs, question = query)

    return res
    # except Exception as e:
    #     print("Received process error: ", e)
    #     # return "An Error occurred!!"
    #     return e

@app.route('/query', methods=['POST'])
def process_request():

    # Debugging...
    for name, value in os.environ.items():
        print("{0}: {1}".format(name, value))

    # try:
    data = request.get_json()
    user_input = data['query']
    response = process_query(user_input)
    return jsonify({"response": response})
    # except Exception as e:
    #     print("Received Process request error: ", e)
    #     return jsonify({"response": str(e)})

## Development phase use case only
# if __name__ == '__main__':
#     app.run(debug=True)