app.py

import faiss
import pickle
import datasets
import numpy as np
import requests
import streamlit as st
from vector_engine.utils import vector_search 
from transformers import AutoModel, AutoTokenizer

from datasets import load_dataset

#@st.cache
@st.cache_data
def read_data(dataset_repo='dhmeltzer/ELI5_embedded'):
    """Read the data from huggingface."""
    return load_dataset(dataset_repo)['train']

@st.cache_data
def load_faiss_index(path_to_faiss="./faiss_index.pickle"):
    """Load and deserialize the Faiss index."""
    with open(path_to_faiss, "rb") as h:
        data = pickle.load(h)
    return faiss.deserialize_index(data)

def main():
    # Load data and models
    data = read_data()
    faiss_index = load_faiss_index()

    model_id="sentence-transformers/all-MiniLM-L6-v2"
    
    api_url = f"https://api-inference.huggingface.co/pipeline/feature-extraction/{model_id}"
    headers = {"Authorization": f"Bearer {st.secrets['HF_token']}"}

    def query(texts):
        response = requests.post(api_url, headers=headers, json={"inputs": texts, "options":{"wait_for_model":True}})
        return response.json()


    st.title("Semantic Search for Questions on Reddit.")

    st.write("""This application lets you perform a semantic search through questions in the r/ELI5 [dataset](https://huggingface.co/datasets/eli5). \
    The questions and user input are encoded into a high-dimensional vectors space using a Sentence-Transformer model, and in particular the checkpoint [sentence-transformers/all-MiniLM-L6-v2](https://huggingface.co/sentence-transformers/all-MiniLM-L6-v2").
    To perform the search we use FAISS, which performs an efficient similarity search through the (vectorized) questions.
    The ELI5 dataset contains posts from three subreddits, AskScience (asks), AskHistorians (askh), and ExplainLikeImFive (eli5).
    The score corresponds to the rating each answer recieved when posted on Reddit.
    \n You can use the slider on the left to change the number of results shown.
    We unfortunately cannot verify the veracity of any of the answers posted!""")

    
    # User search
    user_input = st.text_area("Search box", "What is spacetime made out of?")

    # Filters
    st.sidebar.markdown("**Filters**")
    num_results = st.sidebar.slider("Number of search results", 1, 50, 5)

    vector = query([user_input])
    # Fetch results
    if user_input:
        # Get paper IDs
        _, I = faiss_index.search(np.array(vector).astype("float32"), k=num_results)
        
        # Get individual results
        for id_ in I.flatten().tolist():
            row = data[id_]
            
            answers=row['answers']['text']
            answers_URLs = row['answers_urls']['url']
            for k in range(len(answers_URLs)):
                answers = [answer.replace(f'_URL_{k}_',answers_URLs[k]) for answer in answers]
            
            
            st.write(f"**Title**: {row['title']}")
            st.write(f"**Split**: {row['split']}")
            st.write(f"**Score**: {row['answers']['score'][0]}")
            st.write(f"**Top Answer**: {answers[0]}")
            st.write("-"*20) 



if __name__ == "__main__":
    main()