app.py

import time
import streamlit as st
import logging
from json import JSONDecodeError
from markdown import markdown
import random
from typing import List, Dict, Any, Tuple, Optional
from annotated_text import annotation
from urllib.parse import unquote

from haystack_utils import start_haystack, set_state_if_absent, load_questions

INDEX_DIR = 'data/index'
QUESTIONS_PATH = 'data/questions.txt'
RETRIEVER_MODEL = "sentence-transformers/multi-qa-mpnet-base-dot-v1"
RETRIEVER_MODEL_FORMAT = "sentence_transformers"
READER_MODEL = "deepset/roberta-base-squad2"
READER_CONFIG_THRESHOLD = 0.15
RETRIEVER_TOP_K = 10
READER_TOP_K = 5

# the following function is a wrapper for start_haystack,
# which loads document store, retriever, reader and creates pipeline.
# cached to make index and models load only at start
@st.cache(hash_funcs={"builtins.SwigPyObject": lambda _: None},
          allow_output_mutation=True)
def start_app():
    return start_haystack()


@st.cache()
def load_questions_wrapper():
    return load_questions()

pipe = start_app()

# the pipeline is not included as parameter of the following function,
# because it is difficult to cache
@st.cache(persist=True, allow_output_mutation=True)
def query(question: str, retriever_top_k: int = 10, reader_top_k: int = 5):
    """Run query and get answers"""
    params = {"Retriever": {"top_k": retriever_top_k},
              "Reader": {"top_k": reader_top_k}}
    results = pipe.run(question, params=params)
    return results


def main():

    questions = load_questions()

    # Persistent state
    set_state_if_absent('question', "Where is Twin Peaks?")
    set_state_if_absent('answer', '')
    set_state_if_absent('results', None)
    set_state_if_absent('raw_json', None)
    set_state_if_absent('random_question_requested', False)

    # Small callback to reset the interface in case the text of the question changes
    def reset_results(*args):
        st.session_state.answer = None
        st.session_state.results = None
        st.session_state.raw_json = None

    # sidebar style
    st.markdown(
        """
    <style>
    [data-testid="stSidebar"][aria-expanded="true"] > div:first-child{
        width: 350px;
    }
    [data-testid="stSidebar"][aria-expanded="false"] > div:first-child{
        width: 350px;
        margin-left: -350px;
    }
    """,
        unsafe_allow_html=True,
    )
    # Title
    st.write("# Who killed Laura Palmer?")
    st.write("### The first Twin Peaks Question Answering system!")

    st.markdown("""
Ask any question about [Twin Peaks] (https://twinpeaks.fandom.com/wiki/Twin_Peaks) 
and see if the AI ​​can find an answer...

*Note: do not use keywords, but full-fledged questions.*
""")

    # Sidebar
    st.sidebar.header("Who killed Laura Palmer?")
    st.sidebar.image(
        "https://upload.wikimedia.org/wikipedia/it/3/39/Twin-peaks-1990.jpg")
    st.sidebar.markdown('<p align="center"><b>Twin Peaks Question Answering system</b></p>',
                        unsafe_allow_html=True)
    st.sidebar.markdown(f"""
    <style>
        a {{
            text-decoration: none;
        }}
        .haystack-footer {{
            text-align: center;
        }}
        .haystack-footer h4 {{
            margin: 0.1rem;
            padding:0;
        }}
        footer {{
            opacity: 0;
        }}
        .haystack-footer img {{
            display: block;
            margin-left: auto;
            margin-right: auto;
            width: 85%;
        }}
    </style>
    <div class="haystack-footer">
        <p><a href="https://github.com/anakin87/who-killed-laura-palmer">GitHub</a> - 
        Built with <a href="https://github.com/deepset-ai/haystack/">Haystack</a><br/>
        <small>Data crawled from <a href="https://twinpeaks.fandom.com/wiki/Twin_Peaks_Wiki">
        Twin Peaks Wiki</a>.</small>       
    </p>
    <img src = 'https://static.wikia.nocookie.net/twinpeaks/images/e/ef/Laura_Palmer%2C_the_Queen_Of_Hearts.jpg'/>
    <br/>
    </div>
    """, unsafe_allow_html=True)

    # spotify webplayer
    st.sidebar.markdown("""
    <p align="center">
    <iframe style="border-radius:12px" src="https://open.spotify.com/embed/playlist/38rrtWgflrw7grB37aMlsO?utm_source=generator" width="85%" height="380" frameBorder="0" allowfullscreen="" allow="autoplay; clipboard-write; encrypted-media; fullscreen; picture-in-picture"></iframe>
    </p>""", unsafe_allow_html=True)

    # Search bar
    question = st.text_input("",
                             value=st.session_state.question,
                             max_chars=100,
                             on_change=reset_results
                             )
    col1, col2 = st.columns(2)
    col1.markdown(
        "<style>.stButton button {width:100%;}</style>", unsafe_allow_html=True)
    col2.markdown(
        "<style>.stButton button {width:100%;}</style>", unsafe_allow_html=True)

    # Run button
    run_pressed = col1.button("Run")

    # Get next random question from the CSV
    if col2.button("Random question"):
        reset_results()
        question = random.choice(questions)
        # Avoid picking the same question twice (the change is not visible on the UI)
        while question == st.session_state.question:
            question = random.choice(questions)
        st.session_state.question = question
        st.session_state.random_question_requested = True
        # Re-runs the script setting the random question as the textbox value
        # Unfortunately necessary as the Random Question button is _below_ the textbox
        raise st.script_runner.RerunException(
            st.script_request_queue.RerunData(None))
    else:
        st.session_state.random_question_requested = False

    run_query = (run_pressed or question != st.session_state.question) \
        and not st.session_state.random_question_requested

    # Get results for query
    if run_query and question:
        time_start = time.time()
        reset_results()
        st.session_state.question = question

        with st.spinner(
            "🧠 &nbsp;&nbsp; Performing neural search on documents..."

        ):
            try:
                st.session_state.results = query(
                    question, RETRIEVER_TOP_K, READER_TOP_K)
                time_end = time.time()
                print(f'elapsed time: {time_end - time_start}')
            except JSONDecodeError as je:
                st.error(
                    "👓 &nbsp;&nbsp; An error occurred reading the results. Is the document store working?")
                return
            except Exception as e:
                logging.exception(e)
                st.error("🐞 &nbsp;&nbsp; An error occurred during the request.")
                return

    if st.session_state.results:
        st.write("## Results:")

        alert_irrelevance = True
        if len(st.session_state.results['answers']) == 0:
            st.info("🤔 &nbsp;&nbsp; Haystack is unsure whether any of the documents contain an answer to your question. Try to reformulate it!")

        for count, result in enumerate(st.session_state.results['answers']):
            result = result.to_dict()
            if result["answer"]:
                if alert_irrelevance and result['score'] < 0.50:
                    alert_irrelevance = False
                    st.write("""
                    <h4 style='color: darkred'>Attention, the 
                    following answers have low relevance:</h4>""",
                             unsafe_allow_html=True)

            answer, context = result["answer"], result["context"]
            start_idx = context.find(answer)
            end_idx = start_idx + len(answer)
            # Hack due to this bug: https://github.com/streamlit/streamlit/issues/3190
            st.write(markdown("- ..."+context[:start_idx] +
                              str(annotation(answer, "ANSWER", "#3e1c21")) + context[end_idx:]+"..."),
                     unsafe_allow_html=True)
            source = ""
            name = unquote(result['meta']['name']).replace('_', ' ')
            url = result['meta']['url']
            source = f"[{name}]({url})"
            st.markdown(
                f"**Score:** {result['score']:.2f} -  **Source:** {source}")


main()