Viva Prep

SimpleDemo script pehle se practice: 5–7 min, Admin + User roles, saare mandatory features.

Suggested flow1) Register/login user
2) Admin login — CRUD
3) Approval/blacklist
4) Booking/apply + edge case
5) Search
6) Logout

Viva tipBolte-bolte dikhao. Code tab kholna jab poochhein.

Simplemodels.py = har table ki class: columns, PK/FK, relationships. Yeh Model layer hai.

Suggested flow1) Classes list karo
2) Har table ka kaam 1 line
3) Relationships (1-M / M-M)
4) Constraints (unique, nullable)

Example

class Lot(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(80), nullable=False)
    spots = db.relationship('Spot', backref='lot', lazy=True)

Simpledb.relationship se object graph: lot.spots, booking.user. backref reverse side auto deta hai.

Example

spots = db.relationship('Spot', backref='lot', cascade='all, delete-orphan')

SimplePrimary key row ka unique identity — usually id Integer autoincrement.

Example

id = db.Column(db.Integer, primary_key=True)

SimpleForeign key dusri table ke PK ko point karti hai — relationship banati hai.

Example

lot_id = db.Column(db.Integer, db.ForeignKey('lot.id'), nullable=False)

SimpleORM = Object Relational Mapping. Tables → Python classes. Raw SQL kam likhte ho.

Example

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), unique=True)

User.query.get(5)  # SELECT ... WHERE id=5

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleVertical badi machine. Horizontal aur boxes + load balancer. JWT stateless horizontal friendly.

10k users: Postgres, Redis, gunicorn, CDN, pagination, indexes.
Millions: replicas, queue partition, more workers.

Pehle 1-line definition, phir related MAD2 layer (Vue SFC / Flask route / models.py / tasks.py / Redis).

4-line formula: input kahan se aaya, auth/validation kaunsa, DB ya cache ya Celery, kya return.

Related mix mat karo — cache ≠ Celery, authentication ≠ authorization, v-if ≠ v-show, Beat ≠ Worker. Follow-up ke liye ek difference ready rakho.

Project example: Course app vertical enough. Design answer scale-out.

SimpleAuthentication: tu kaun hai? (login). Authorization: tujhe permission hai? (role check).

Example

# auth
if check_password_hash(user.password, pwd):
    session['user_id'] = user.id

# authz
if user.role != 'admin':
    abort(403)

Difference question hai — 3 cheezein bolo: meaning, kab use, 1 example.

Pehle concept A ek line, phir B ek line, phir table-jaisa farq (input/output/side-effect).
Example hamesha MAD1 se: GET search page, POST register, PUT/PATCH API update, session vs cookie login.

SimpleTheory = concepts: ORM, MVC, auth vs authz, Jinja inheritance, sessions. 1-line def + project example.

SimpleExaminer portal wala submitted ZIP chahta hai. Local extra changes mat dikhana.

Suggested flow1) Portal ZIP download
2) Extract
3) venv + pip install -r requirements.txt
4) flask run / python app.py

SimpleLogin flow pehle poochta hai "tu kaun hai?", token milne ke baad har API pe wohi proof dikhate ho.

Authentication step: Vue form email + password JSON POST karta hai. Flask user dhoondhta hai, check_password_hash se prove karta hai ki tum genuine ho. Galat 401. Sahi pe JWT + role milta hai — yeh session/token hai.

Vue localStorage (ya cookie) mein token rakhta hai, dashboard pe router.push. Aage ki har fetch header: Authorization: Bearer <token>. @jwt_required identity check (authentication). @roles_required('admin') permission check (authorization) — logged in ho, lekin allowed nahi to 403.

Validation alag cheez hai: empty email, password 8+ — form sahi bhara hai ya nahi. Woh identity prove nahi karta.

Logout = client token delete + login page. Server blacklist optional. Password response JSON mein kabhi mat bhejo.

Example

# Authentication
@app.route('/api/login', methods=['POST'])
def login():
    u = User.query.filter_by(email=data['email']).first()
    if not u or not check_password_hash(u.password, data['password']):
        return jsonify(msg='bad'), 401
    return jsonify(token=create_access_token(u.id), role=u.role)

# baad ki APIs
# Authorization: Bearer <token>
if current_user.role != 'admin':
    abort(403)

Project example: Login.vue POST /api/login → token LS → interceptor. Student token se admin route = 403. Empty form = validation, galat password = 401.

Viva tipNetwork tab mein password body dikhega localhost pe — prod HTTPS. Response mein hash/password echo mat karo.

SimpleSMTP = Simple Mail Transfer Protocol — email bhejne ka standard. Flask-Mail / smtplib se reminders/reports.

Example

from flask_mail import Message
msg = Message('Subject', recipients=[user.email])
msg.body = 'Hello'
mail.send(msg)

Viva tipViva mein MailHog/inbox dikhao. Port 587 TLS common; local pe MailHog 1025.

SimpleCache = pehli baar hisaab karke copy rakh lo, doosri baar copy dikha do.

Baar-baar same expensive kaam (DB query, counting bookings) mat karo. Result Redis jaise store mein timeout ke saath rakh do.

Cache hit: key mil gayi, DB skip. Cache miss: DB se lao, SET karo, return karo.

Tradeoff: speed vs stale data. Admin naya venue add kare aur cache 50s ka ho to user purani list dekh sakta hai — isliye write pe invalidation zaroori hai.

Browser cache, Flask-Caching, Redis alag layers hain. MAD2 examiner Redis + @cache.cached code dekhta hai.

Example

@cache.cached(timeout=50, query_string=True)
@app.route('/api/shows')
def shows():
    return jsonify([s.serialize() for s in Show.query.all()])

Project example: Admin dashboard counts / venues list cache. Create/update/delete ke baad cache.delete('venues').

Viva tipprint('DB queried') function ke andar laga ke miss/hit demo karo — hit pe print nahi chalega.

SimpleClick → Celery → worker CSV → email/download. Columns verify.

csv module. Auth required. Don't freeze UI — 202 + poll.

Examiner 2 cheezein: simple desi line + tumhare project ki exact file.

Pehle ID, GitHub, portal ZIP. Phir run: Redis + Flask + worker + beat + Vue. Feature demo: login, RBAC, cache hit/miss, Celery mail, search.

Line pe ungli: input kahan, kaunsa check, query/cache/task, JSON/UI. Copilot band. Jo nahi kiya honestly bolo + kaise add karte.

Example

@celery.task
def export_venues_csv(user_id):
    rows = Venue.query.all()
    # csv.writer, mail.send
    return 'ok'

Project example: Admin export venues. MailHog attach ya file open.

Viva tipNetwork tab mein job trigger API dikhao, phir MailHog/file open karke columns verify karo.

SimpleLevel = viva difficulty band. Level 1 usually demo + basics; higher pe live coding + deeper theory.

Viva tipJo level assign hai uske hisaab se demo + theory ready rakho.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.

Viva tipFunction signature + 3-4 important lines + edge case.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleDemo script pehle se practice: 5–7 min, Admin + User roles, saare mandatory features.

Suggested flow1) Register/login user
2) Admin login — CRUD
3) Approval/blacklist
4) Booking/apply + edge case
5) Search
6) Logout

Viva tipBolte-bolte dikhao. Code tab kholna jab poochhein.

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.

Viva tipFunction signature + 3-4 important lines + edge case.

SimpleDemo script pehle se practice: 5–7 min, Admin + User roles, saare mandatory features.

Suggested flow1) Register/login user
2) Admin login — CRUD
3) Approval/blacklist
4) Booking/apply + edge case
5) Search
6) Logout

Viva tipBolte-bolte dikhao. Code tab kholna jab poochhein.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.

Viva tipFunction signature + 3-4 important lines + edge case.

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.

Viva tipFunction signature + 3-4 important lines + edge case.

SimpleJWT teen tukde ki signed chitthi: header.payload.signature. Padhi ja sakti hai, badli nahi ja sakti.

Encoded (Base64) + signed, encrypted nahi (JWE alag). Payload mein password mat daalo — koi jwt.io pe dekh lega.

Login pe server secret se HMAC (HS256). Har API Authorization: Bearer <token>.
Expiry exp. Change payload → signature fail → 401.

Session MAD1 server yaad rakhta. JWT MAD2 client rakhta, server stateless-ish.

Example

eyJhbGciOiJIUzI1NiJ9.{"sub":1,"role":"admin"}.signature
# Authorization: Bearer <token>

Project example: POST /login → token LS. fetch interceptor header. @jwt_required APIs.

Viva tipAlgo HS256. Secret env var. jwt.io pe payload dikhao, secret public site pe mat paste.

Simplevar old function-scope, let block-scope changeable, const block-scope reassign nahi.

var x = 1; // hoisted, function scoped — avoid
let count = 0; count = 1; // theek
const PI = 3.14; // reassign error, object ke andar field change ho sakti hai
Modern JS: let/const use karo, var mat karo.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleTheory = concepts: ORM, MVC, auth vs authz, Jinja inheritance, sessions. 1-line def + project example.

SimpleCode explain formula: input kya aaya → auth/validation → DB change → response/UI.

Viva tipFunction signature + 3-4 important lines + edge case.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleViva wrap-up hai. Short thanks + confirm submission ZIP latest hai.

SimpleCelery = background naukri. HTTP request ko 10 second email bhejne ke liye mat rokna.

Distributed task queue: aap function ko abhi nahi, worker process mein later/retry/schedule pe chalaate ho.

MAD2 typical jobs: daily reminder mail, monthly HTML report, user-triggered CSV export.

Web request 200ms hona chahiye. 10,000 emails request thread mein = timeout. Worker alag CPU pe kaam kare.

Redis broker chahiye. Beat alag process schedule ke liye.

Example

@celery.task
def daily_reminder():
    for u in User.query.filter_by(active=True):
        send_mail(u.email, 'Book something today!')

Project example: User Export click → 202 Accepted. Worker CSV + email. Daily 6pm Beat reminder.

Viva tipWorker + Redis bina Beat ke user-triggered chalega. Scheduled jobs ke liye Beat bhi chahiye.

SimpleFlask lightweight Python web framework — routes, request/response, templates. MAD1 ka backend yahi hai.

Example

from flask import Flask
app = Flask(__name__)

@app.route('/')
def home():
    return 'Hello'

Viva tipFlask micro hai: jo chahiye (DB, login, forms) khud jodte ho.

SimpleAuthentication: tu kaun hai? (login). Authorization: tujhe permission hai? (role check).

Example

# auth
if check_password_hash(user.password, pwd):
    session['user_id'] = user.id

# authz
if user.role != 'admin':
    abort(403)

SimpleMAD1 mein usually session-based auth: login pe session['user_id'], har request pe verify.

Example

session['user_id'] = user.id
uid = session.get('user_id')
user = User.query.get(uid)

Viva tipSECRET_KEY set karo warna session insecure. logout pe session.clear().

Simplevenv activate → dependencies → DB create/migrate → flask run. Browser pe localhost dikhao.

Example

python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
flask run

SimpleMAD1 mein usually session-based auth: login pe session['user_id'], har request pe verify.

Example

session['user_id'] = user.id
uid = session.get('user_id')
user = User.query.get(uid)

Viva tipSECRET_KEY set karo warna session insecure. logout pe session.clear().

SimpleSQLite file-based DB — setup easy, MAD1 ke liye perfect. Production heavy traffic pe Postgres better.

Example

SQLALCHEMY_DATABASE_URI = 'sqlite:///app.db'

SimpleDifferent origin Vue vs Flask — browser CORS check. Server Allow-Origin.

Failed = frontend error even if curl works. Examiner curl vs browser.

HTTP verbs + status REST ki zabaan. GET read, POST create, PUT replace, PATCH partial, DELETE remove. GET typically no body.

Status: 200 OK, 201 created, 202 accepted (Celery task), 400 bad input, 401 no/bad token, 403 role nahi, 404 missing, 409 conflict (double book), 500 server.

AJAX/fetch page reload nahi. SPA poori isi pe. Postman se bina Vue ke API prove karo — examiner pasand.

Example

from flask_cors import CORS
CORS(app, resources={r'/api/*': {'origins': 'http://localhost:8080'}})

Project example: Flask-CORS localhost:8080.

Simplevar old function-scope, let block-scope changeable, const block-scope reassign nahi.

var x = 1; // hoisted, function scoped — avoid
let count = 0; count = 1; // theek
const PI = 3.14; // reassign error, object ke andar field change ho sakti hai
Modern JS: let/const use karo, var mat karo.

SimpleJavaScript browser/Node pe chalta hai — DOM, events, fetch/axios. MAD1 mein thoda JS; MAD2 mein Vue JS pe.