sdlc-project/backend/src/main.py

from flask import Flask, request
import psycopg2 as psql
from os import environ as env
import datetime
import time
import threading
import uuid

app = Flask(__name__)

db_params = {
    'database': env.get('DB_NAME'),
    'user': env.get('DB_USER'),
    'password': env.get('DB_PASS'),
    'host': env.get('DB_HOST'),
    'port': int(env.get('DB_PORT'))
}

db = None

for _ in range(5):
    try:
        db = psql.connect(**db_params)
    except Exception as e:
        print(f"Failed to connect ({e}), retrying...")
        time.sleep(5)

class PassQueue:
    def __init__(self):
        self.queue = []

    def start(self):
        while True:
            if not self.queue:
                time.sleep(1)
                continue

            p = self.queue.pop(0)
            c = db.cursor()

            try:
                c.execute("BEGIN")
                c.execute(f"INSERT INTO public.pass (uuid, movie_uuid, user_first, user_last, user_email, pass_type, pass_price, pass_requested_at, payment_received)"
                          f"VALUES ('{uuid.uuid4().hex}', '{p.movie_uuid}', '{p.first}', '{p.last}', '{p.email}', {p.type}, {p.price}, '{time.strftime('%Y-%m-%d %H:%M:%S')}', false)")
                c.execute("COMMIT")
                db.commit()
            except Exception as e:
                print(e)
                c.execute("ROLLBACK")
                db.rollback()

pq = PassQueue()
pq_thread = threading.Thread(target = pq.start, args = [])
pq_thread.start()

@app.route("/movies", methods = ['GET'])
def movies():
    c = db.cursor()

    fields = ['uuid',
              'name',
              'scheduled_datetime',
              'movie_details',
              'image_url',
              'max_passes']

    try:
        c.execute(f"SELECT {','.join(fields)} FROM public.movie")
    except Exception as e:
        c.close()
        print(e)
        return {
                "error": "Failed to list movies",
                "result": None
        }, 503

    res = c.fetchall()
    c.close()

    return {
        "error": "",
        "result": [{fields[i]: v
                    if type(v) != datetime.datetime
                    else v.strftime("%Y-%m-%d %H:%M:%S")
                    for i, v in enumerate(r)}
                    for r in res]
    }

@app.route("/movie/<movie_uuid>", methods = ['GET'])
def movie_byid(movie_uuid):
    c = db.cursor()

    fields = ['name',
              'scheduled_datetime',
              'movie_details',
              'image_url',
              'max_passes']

    try:
        c.execute(f"SELECT {','.join(fields)} FROM public.movie WHERE uuid='{movie_uuid}'")
    except Exception as e:
        c.close()
        print(e)
        return {
                "error": "Failed to search for a movie",
                "result": None
        }, 503

    res = c.fetchone()
    c.close()

    if res:
        return {
            "error": "",
            "result": {fields[i]: v
                       if type(v) != datetime.datetime
                       else v.strftime("%Y-%m-%d %H:%M:%S")
                       for i, v in enumerate(res)}
        }
    else:
        return {
            "error": f"No movie with uuid={movie_uuid} has been found",
            "result": None
        }, 404

@app.route("/passes", methods = ['GET'])
def passes():
    c = db.cursor()

    fields = ["uuid",
              "movie_uuid",
              "user_first",
              "user_last",
              "user_email",
              "pass_type",
              "pass_price",
              "pass_requested_at",
              "payment_received",
              "payment_received_at"]

    try:
        c.execute(f"SELECT {','.join(fields)} FROM public.pass")
    except Exception as e:
        c.close()
        print(e)
        return {
                "error": "Failed to list out passes",
                "result": None
        }

    res = c.fetchall()
    c.close()

    return {
        "error": "",
        "result": [{fields[i]: v
                    if type(v) != datetime.datetime
                    else v.strftime("%Y-%m-%d %H:%M:%S")
                    for i, v in enumerate(r)}
                    for r in res]}

class PassValidator:
    def __init__(self):
        self.first = None
        self.last = None
        self.email = None
        self.type = None
        self.price = None
        self.movie_uuid = None

    def validate(self):
        if not self.first:
            return "First name missing"
        elif not self.last:
            return "Last name missing"
        elif not self.email:
            return "Email missing"
        elif not self.type:
            return "Pass type missing"
        elif not self.price:
            return "Pass price missing"
        elif not self.movie_uuid:
            return "Movie uuid missing"

    def queue(self):
        pq.queue.append(self)

def fill_pass_from_form(p, f):
    print(f)

def fill_pass_from_json(p, j):
    fields = ("first",
              "last",
              "email",
              "type",
              "price",
              "movie_uuid")

    for i in fields:
        exec(f"p.{i} = j.get('{i}')")

@app.route("/apply_for_pass", methods = ['POST'])
def apply_for_pass():
    p = PassValidator()

    if request.form:
        fill_pass_from_form(p, request.form)
    elif request.is_json:
        fill_pass_from_json(p, request.json)
    else:
        return {"error": "only form and json interfaces are supported", "result": None}, 403

    v = p.validate()

    if not v:
        p.queue()
        return {"error": None, "result": "OK"}
    else:
        return {"error": v, "result": None}