app/main.py

import os
import logging
import shutil
import time
import re
from typing import List
from fastapi import FastAPI, UploadFile
from fastapi.middleware import Middleware
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import StreamingResponse
from .rag import ChatPDF

middleware = [
    Middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_methods=['*'],
        allow_headers=['*']
    )
]

app = FastAPI(middleware=middleware)

files_dir = os.path.expanduser("~/wtp_be_files/")
session_assistant = ChatPDF()

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


def astreamer(generator):
    t0 = time.time()
    for i in generator:
        logger.info(f"Chunk being yielded (time {int((time.time()-t0)*1000)}ms)")
        yield i
    logger.info(f"Over (time {int((time.time()-t0)*1000)}ms)")


@app.get("/query")
async def process_input(text: str):
    generator = None
    if text and len(text.strip()) > 0:
        if session_assistant.pdf_count > 0:
            text = text.strip()
            streaming_response = session_assistant.ask(text)
            generator = streaming_response.response_gen
        else:
            message = "Please add a PDF document first."
            generator = re.split(r'(\s)', message)
    else:
        message = "The provided query is empty."
        generator = re.split(r'(\s)', message)
    return StreamingResponse(astreamer(generator), media_type='text/event-stream')


@app.post("/upload")
def upload(files: list[UploadFile]):  
    try:
        os.makedirs(files_dir)
        for file in files:
            try:
                path = f"{files_dir}/{file.filename}"
                file.file.seek(0)
                with open(path, 'wb') as destination:
                    shutil.copyfileobj(file.file, destination)
            finally:
                file.file.close()
    finally:
        session_assistant.ingest(files_dir)
        shutil.rmtree(files_dir)

    message = "Files inserted successfully."
    generator = re.split(r'(\s)', message)
    return StreamingResponse(astreamer(generator), media_type='text/event-stream')


@app.get("/clear")
def ping():
    session_assistant.clear()
    message = "All files have been cleared."
    generator = re.split(r'(\s)', message)
    return StreamingResponse(astreamer(generator), media_type='text/event-stream')


@app.get("/")
def ping():
    return "Pong!"