lib/st_custom_components.py

import os
import numpy as np
import streamlit as st
from io import BytesIO
import streamlit.components.v1 as components

def st_audiorec():

    # get parent directory relative to current directory
    parent_dir = os.path.dirname(os.path.abspath(__file__))
    # Custom REACT-based component for recording client audio in browser
    build_dir = os.path.join(parent_dir, "st_audiorec/frontend/build")
    # specify directory and initialize st_audiorec object functionality
    st_audiorec = components.declare_component("st_audiorec", path=build_dir)

    # Create an instance of the component: STREAMLIT AUDIO RECORDER
    raw_audio_data = st_audiorec()  # raw_audio_data: stores all the data returned from the streamlit frontend
    wav_bytes = None                # wav_bytes: contains the recorded audio in .WAV format after conversion

    # the frontend returns raw audio data in the form of arraybuffer
    # (this arraybuffer is derived from web-media API WAV-blob data)

    if isinstance(raw_audio_data, dict):  # retrieve audio data
        with st.spinner('retrieving audio-recording...'):
            ind, raw_audio_data = zip(*raw_audio_data['arr'].items())
            ind = np.array(ind, dtype=int)  # convert to np array
            raw_audio_data = np.array(raw_audio_data)  # convert to np array
            sorted_ints = raw_audio_data[ind]
            stream = BytesIO(b"".join([int(v).to_bytes(1, "big") for v in sorted_ints]))
            # wav_bytes contains audio data in byte format, ready to be processed further
            wav_bytes = stream.read()

    return wav_bytes