server.py

import os, math, json

from flask import Flask, request
from functools import lru_cache

from search import init_colbert, search_colbert

PORT = int(os.getenv("PORT", 8893))
app = Flask(__name__)

counter = {"api" : 0}

# Load data
COLLECTION_PATH = 'collection.json'
DATASET_PATH    = 'dataset.json'

with open(COLLECTION_PATH, 'r', encoding='utf-8') as f:
    collection = json.loads(f.read())
with open(DATASET_PATH, 'r', encoding='utf-8') as f:
    dataset = json.loads(f.read())
dataset = [d for d in dataset if 'abstract' in d.keys()] # We only indexed the entries containing abstracts


@lru_cache(maxsize=1000000)
def api_search_query(query, k):
    print(f"Query={query}")

    k = 10 if k == None else min(int(k), 100)

    # Use ColBERT to find passages related to the query
    pids, ranks, scores = search_colbert(query, k)

    # Softmax output probs
    probs = [math.exp(s) for s in scores]
    probs = [p / sum(probs) for p in probs]

    # Compile and return using the API
    topk = []
    for pid, rank, score, prob in zip(pids, ranks, scores, probs):
        topk += [{
            'text': collection[pid], 
            'pid': pid, 
            'rank': rank, 
            'score': score, 
            'prob': prob,
            'entry': dataset[pid]
        }]
    
    topk = list(sorted(topk, key=lambda p: (-1 * p['score'], p['pid'])))
    return {"query" : query, "topk": topk}


@app.route("/api/search", methods=["GET"])
def api_search():
    if request.method == "GET":
        counter["api"] += 1
        print("API request count:", counter["api"])
        return api_search_query(request.args.get("query"), request.args.get("k"))
    else:
        return ('', 405)


if __name__ == "__main__":
    """
    Example usage:
    python server.py
    http://localhost:8893/api/search?k=25&query=How to extend context windows?
    """
    init_colbert()
    # test_response = api_search_query("What is NLP?", 2)
    # print(test_response)
    print(f'Test it at: http://localhost:8893/api/search?k=25&query=How to extend context windows?')
    app.run("0.0.0.0", PORT)