server.py

from flask import Flask, request, render_template
from sqlalchemy import create_engine, text

app = Flask(__name__)
engine = create_engine("postgresql://gaoyb7@localhost/dht_demo")
conn = engine.connect()

@app.route("/")
def index():
    return render_template("base.html", total_torrents=torrents_count())


@app.route("/search")
def search():
    kw = request.args.get("kw").strip()
    kw = ":* & ".join(kw.split()) + ":*"

    precheck_cmd = '''select to_tsquery('english', '%s')''' % kw
    r = conn.execute(precheck_cmd)
    print(precheck_cmd)
    if r.fetchone()[0] == "":
        return "None"

    cmd = '''select * from hash_tab where to_tsvector('english', name) @@ \
            to_tsquery('english', '%s')''' % kw
    r = conn.execute(cmd)
    counts = r.rowcount
    result = []
    cnt = 0
    for item in r:
        cnt += 1
        if cnt > 100:
            break
        result.append((item[0], item[1]))

    print("ok")
    return render_template("search.html", match_torrents_count=counts, 
        total_torrents=torrents_count(), result=result)


def to_magnet(infohash, name):
    magnet_base = "magnet:?xt=urn:btih:" + infohash
    magnet = magnet_base + "&dn=" + name
    return magnet


def torrents_count():
    cmd = "select count(*) from hash_tab"
    r = conn.execute(cmd)
    for item in r:
        return item[0]


if __name__ == "__main__":
    app.template_folder = "simServer/templates"
    app.debug = False
    app.run(host="0.0.0.0", port=5000)