Proctor Level2_94

SimpleCamera pe clearly college/IITM ID dikhao — naam aur photo match hone chahiye.

Viva tipPehle se ID haath mein rakho, glare mat aane do. Iske baad GitHub + project run.

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.

Example

/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }

Viva tipDevTools se pehle try, phir file mein permanent change.

SimpleJS variables: var (function scope, old), let (block), const (block, reassign nahi).

Example

let count = 0;
const API = '/api';

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')

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.

Simpleextends poora layout inherit karta hai, include chhota piece insert karta hai.

extends: child page base.html ka structure use karti hai, blocks override karti hai. Ek hi parent.
include: navbar.html / footer.html jahan chaho insert. Kai baar use ho sakta hai.

base.html:

{% block content %}{% endblock %}

home.html:
{% extends 'base.html' %}
{% block content %}<h1>Home</h1>{% endblock %}

{% include 'navbar.html' %}  → navbar har page pe

Fayda: header/footer ek jagah, change once — saari pages update. MAD1 mein almost har project use karta hai.

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.

Example

# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error

SimpleInt column mein string daalne pe SQLAlchemy/DB type error ya Integrity/StatementError. Empty table pe bhi same validation fail — row count matter nahi.

Example

# SQLite may coerce sometimes; Postgres: invalid input syntax for integer
Spot(status='free', lot_id='abc')  # lot_id int → error

SimpleJWT = JSON Web Token — signed string jisme user id/role hota hai. Har request header mein jaata hai. Session server pe store, JWT client pe.

Login → server token deta hai → Authorization: Bearer <token>
Payload: {sub: user_id, role: admin, exp: ...} — padha ja sakta hai, change nahi (signature).
Session: browser cookie, server-rendered Flask ke liye simple.
Token: mobile/Vue SPA, scaling (server memory nahi). Store: memory/httpOnly cookie, localStorage XSS risk.
MAD1 mostly session. Flask-Security session+login, JWT APIs ke liye.

Simplebackref reverse attribute auto banata hai. back_populates dono sides explicitly naam dete ho — clearer.

Example

# backref
spots = db.relationship('Spot', backref='lot')
# spot.lot available

# back_populates
spots = db.relationship('Spot', back_populates='lot')
# Spot.lot = db.relationship('Lot', back_populates='spots')

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().

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

SimpleCSRF = Cross-Site Request Forgery — logged-in user ke browser se attacker site hidden form submit karwati hai.

FixCSRF token hidden field, server verify. Flask-WTF: {{ form.hidden_tag() }}

SameSite cookies bhi help. GET pe destructive action mat rakho.

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.

SimpleLive UI change: relevant CSS/HTML template kholo — color, margin, flex, bootstrap class. Save + hard refresh.

Example

/* button red */
.btn-primary { background: red; }

/* center navbar item */
.navbar { justify-content: center; }

Viva tipDevTools se pehle try, phir file mein permanent change.

SimpleMutations sync diary entry. Actions async kaam phir diary.

Direct state mutate action se Vuex 4 discouraged. Devtools time-travel mutations.

Purpose of Actions: API, phir commit. Purpose of Mutations: state change one place.

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: action fetchVenues → commit setVenues. Mutation sirf array replace.

SimpleLifecycle = component ki zindagi ke stages. API call tab jab DOM ready ho — mounted.

created: instance bani, this data, DOM nahi. mounted/onMounted: page pe aa gaya — fetch, Chart.js, setInterval.
updated: data change ke baad. unmounted: cleanup (clearInterval) warna memory leak.

Dashboards onMounted isliye: canvas/API tab valid. created mein $el nahi.

Composition: onMounted(() => {}) setup ke andar.

Example

export default {
  async mounted() {
    const r = await fetch('/api/venues')
    this.venues = await r.json()
  }
}

Project example: Venues.vue mounted fetch list. Clock component unmounted pe interval clear.

Viva tipcreated: data setup, DOM nahi. mounted/onMounted: $el mil gaya — fetch yahi. Dashboards isliye onMounted use karti hain.

SimplePrivacy personal data minimize. Security attacks rokna CIA. Overlap not same.

GDPR vs firewall example.

Browser + API ke beech extra darwaze: CORS origin allow, HTTPS encrypt transit, CSRF cookie-auto-send attack, XSS HTML inject, SQL injection raw query.

MAD2 SPA: Vue :8080 Flask :5000 → Flask-CORS. JWT localStorage XSS se chori ho sakta — v-html user input pe avoid. Password Network tab localhost pe dikhega; prod HTTPS, response mein password echo nahi.

401 unauthenticated, 403 unauthorized, 400 validation. Hash one-way — SHA decrypt nahi hota. Secret key .env, GitHub pe nahi.

Project example: Don't return other users' emails to normal user API.

SimpleCascade parent delete pe children pe kya ho: delete-orphan related rows hata deta hai.

Example

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

Viva tipParking lot delete → uske spots/bookings policy clear bolo.

SimpleSQLAlchemy MAD1 ka common ORM. Flask-SQLAlchemy wrapper se db.Model, db.session.

Example

user = User(email='a@b.com')
db.session.add(user)
db.session.commit()
users = User.query.filter_by(role='admin').all()

SimpleVue = UI ka smart assistant. Data badlo, screen khud update. MAD1 Jinja har click pe naya HTML.

Progressive frontend framework. Components, reactivity, directives.

MAD2 SPA: ek index.html, Vue Router pages, Flask sirf JSON.

Fayde: easy, SFC, docs. Vs React: templates HTML-like, course sikhata hai. Vs plain JS: baar-baar DOM mat chhedo.

Example

<!-- HelloWorld.vue -->
<template>
  <h1>{{ msg }}</h1>
</template>
<script>
export default { data() { return { msg: 'Hello' } } }
</script>

Project example: Navbar.vue + views (Login, Dashboard). data() / setup() reactive. fetch APIs.

Viva tipFayde: easy, SFC, reactivity. Vs React: chhota learning curve. Vs plain JS: UI state auto-update.

SimpleRedis fridge pe sticky note hai — poori kitchen (database) kholne ki zarurat nahi.

Redis in-memory key-value store hai. Data RAM mein rehta hai, isliye disk wale SQLite/Postgres se kai guna tez.

MAD2 mein Redis do kaam karta hai:
1) Cache — same venue/show/dashboard JSON baar-baar DB se mat nikaalo.
2) Celery message broker — Flask task queue mein daalta hai, worker uthata hai.

Source of truth database hi hai. Redis band ho to cache miss ho jaata hai aur Celery queue ruk sakti hai. Crash pe cache gayab ho sakta hai — isliye important data sirf Redis mein mat rakho.

Example

import redis
r = redis.Redis(host='localhost', port=6379, db=0)
r.set('venues', json.dumps(data), ex=30)
print(r.get('venues'))

Project example: GET /api/venues pehle Redis dekho. Miss pe SQLAlchemy query, phir SET with timeout. Celery worker Redis list se daily reminder uthata hai.

Viva tipCache ke liye db=1, broker ke liye db=0 rakhna smart hai taaki keys mix na hon. Viva mein redis-cli ping → PONG dikhana strong 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.

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

SimpleLoad badhe to handle: scale up/out, cache, async, DB tune.

SQL scale: indexes, pool, replicas, partition, cache hot queries.

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: If 10k: URI postgres, gunicorn, cache, celery concurrency.

SimpleDemo script pehle se practice karo, 5-7 minute, saari roles.

Suggested flow

1) Register/login user 2) Admin login — CRUD 3) Approval/blacklist 4) Booking/apply 5) Search 6) Validation edge (slots 0, duplicate) 7) Logout
Bolte-bolte dikhao: 'Yahan overbooking rokta hoon'. Code tab kholna jab poochhein.
Crash ho to debug calmly: terminal error, typo, DB path.
Mandatory features skip mat karna — examiner list tick karta hai.

Yeh live UI/CSS change hai. Examiner jo element bole uski CSS turant badlo.

Bootstrap class badlo (btn-primary → btn-success, bg-dark → bg-warning) ya inline style='color:red; background:#eee'.
Center: d-flex justify-content-center text-center. Navbar neeche: navbar fixed-bottom.

Example

<button class='btn btn-success' style='background:#16a34a'>Book</button>

Pehle browser inspect karke class dhundo, phir template mein change karke refresh.

Yeh live UI/CSS change hai. Examiner jo element bole uski CSS turant badlo.

Bootstrap class badlo (btn-primary → btn-success, bg-dark → bg-warning) ya inline style='color:red; background:#eee'.
Center: d-flex justify-content-center text-center. Navbar neeche: navbar fixed-bottom.

Example

<button class='btn btn-success' style='background:#16a34a'>Book</button>

Pehle browser inspect karke class dhundo, phir template mein change karke refresh.

SimpleRelationships tables ko jodti hain taaki related data object se mil jaaye.

One-to-Many: User → kai Posts. posts = relationship('Post', backref='author'). FK post.user_id.
One-to-One: User → Profile. uselist=False + unique FK. Profile.user_id unique.
Many-to-Many: Student ↔ Drive. Junction/secondary table (student_id, drive_id).

Example 1-1:

class Profile(db.Model):
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), unique=True)
    user = db.relationship('User', back_populates='profile', uselist=False)

1-M ko 1-1: child FK pe unique=True + uselist=False.
Parent-child: parent PK, child FK. Junction table extra columns bhi rakh sakti hai (applied_on).

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

Viva mein file khol ke bolo:
1) Kaunsi classes/tables hain (User, Role-specific, Booking...)
2) Har table ka kaam 1 line
3) Relationships: 1-1 / 1-M / M-M, backref, cascade, lazy
4) Constraints: unique email, nullable, default status

Example skeleton

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String(120), unique=True, nullable=False)
    role = db.Column(db.String(20), default='user')
    bookings = db.relationship('Booking', backref='user', cascade='all, delete-orphan')

ER diagram: rectangles entities, lines relationships, PK/FK mark. Schema = yahi structure.
Tables create: db.create_all() ya migrations. SQLite file SQL viewer se dikha sakte ho.

Simpleextends poora layout inherit karta hai, include chhota piece insert karta hai.

extends: child page base.html ka structure use karti hai, blocks override karti hai. Ek hi parent.
include: navbar.html / footer.html jahan chaho insert. Kai baar use ho sakta hai.

base.html:

{% block content %}{% endblock %}

home.html:
{% extends 'base.html' %}
{% block content %}<h1>Home</h1>{% endblock %}

{% include 'navbar.html' %}  → navbar har page pe

Fayda: header/footer ek jagah, change once — saari pages update. MAD1 mein almost har project use karta hai.

SimpleVue.js frontend framework — reactive UI components. MAD2 mein common, MAD1 optional.

Component: reusable UI (Navbar.vue) + data + template.
Props: parent → child data. Child → parent: $emit('update', val).
Slots: parent child ke andar extra HTML daal sakta hai.
Lifecycle: created (data setup), mounted (DOM ready — API call), updated, unmounted.
v-model two-way bind. Vue Router SPA routes (routes.js). Vuex/Pinia global state; mutations sync change, actions async.
Standalone component: khud ke saath compile, parent register kam.

SimpleVue.js frontend framework — reactive UI components. MAD2 mein common, MAD1 optional.

Component: reusable UI (Navbar.vue) + data + template.
Props: parent → child data. Child → parent: $emit('update', val).
Slots: parent child ke andar extra HTML daal sakta hai.
Lifecycle: created (data setup), mounted (DOM ready — API call), updated, unmounted.
v-model two-way bind. Vue Router SPA routes (routes.js). Vuex/Pinia global state; mutations sync change, actions async.
Standalone component: khud ke saath compile, parent register kam.

SimpleVue.js frontend framework — reactive UI components. MAD2 mein common, MAD1 optional.

Component: reusable UI (Navbar.vue) + data + template.
Props: parent → child data. Child → parent: $emit('update', val).
Slots: parent child ke andar extra HTML daal sakta hai.
Lifecycle: created (data setup), mounted (DOM ready — API call), updated, unmounted.
v-model two-way bind. Vue Router SPA routes (routes.js). Vuex/Pinia global state; mutations sync change, actions async.
Standalone component: khud ke saath compile, parent register kam.

SimpleCSRF = Cross-Site Request Forgery — logged-in user ke browser se attacker site hidden form submit karwati hai.

FixCSRF token hidden field, server verify. Flask-WTF: {{ form.hidden_tag() }}

SameSite cookies bhi help. GET pe destructive action mat rakho.

SimpleCORS browser rule hai ki kaunsa frontend kis API ko call kar sake. XSS attacker ka JS tumhare page pe chalaata hai.

CORS: API header Access-Control-Allow-Origin. Vue (localhost:8080) Flask (5000) ko call kare to CORS chahiye. Same Flask+Jinja site pe usually issue nahi.
XSS: <script> cookie chori. Fix: escape output (Jinja autoescape), user HTML mat render karo.
CSRF alag: attacker user ke browser se hidden request. Fix: CSRF token (Flask-WTF).

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.

SimpleCascade parent ke saath child pe automatic action (generally delete).

Company delete → uski drives bhi delete, warna orphan rows / FK error.
SQLAlchemy: db.relationship('Drive', cascade='all, delete-orphan', backref='company')
SQL: ForeignKey(..., ondelete='CASCADE')

Cascade sirf delete nahi: save-update, merge, refresh-expire, expunge, delete-orphan.
Cascade Update: parent PK change to child FK update (rare, PK mat badlo).
Parent delete jab children active hon: constraint error, ya cascade se children gayab, ya pehle children handle karo — design choice examiner poochta hai.
CSS cascading alag topic hai (styles inherit/override).

SimpleSQLAlchemy Python ka sabse popular ORM hai. MAD1 mein Flask-SQLAlchemy wrapper use hota hai.

db = SQLAlchemy(app)

class Book(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(80), nullable=False)

Operations: db.session.add(obj), .commit(), .delete(obj), Model.query.all(), .filter_by(), .get_or_404(id).
db.Model ek class hai (function nahi). db object engine + session + metadata hold karta hai.

SQLALCHEMY_TRACK_MODIFICATIONS=False extra signals band karta hai, performance warning hatati hai.

SimpleCelery background tasks (email, CSV, reports) async chalaata hai. Redis broker/queue + cache.

User 'Export' click → Celery task queue → Redis message → worker CSV banaata hai → user baad mein download.
Saath isliye: Celery ko broker chahiye, Redis tez in-memory. MAD2 topic zyada, MAD1 mein optional.
Priority: task queues/routing. Caching: Redis mein key-value, DB hits kam.
Pub/Sub: publisher channel pe message, subscribers sunte hain — Redis yeh bhi karta hai.

SimpleCelery background tasks (email, CSV, reports) async chalaata hai. Redis broker/queue + cache.

User 'Export' click → Celery task queue → Redis message → worker CSV banaata hai → user baad mein download.
Saath isliye: Celery ko broker chahiye, Redis tez in-memory. MAD2 topic zyada, MAD1 mein optional.
Priority: task queues/routing. Caching: Redis mein key-value, DB hits kam.
Pub/Sub: publisher channel pe message, subscribers sunte hain — Redis yeh bhi karta hai.

SimpleValidation galat data rok ti hai — frontend turant, backend must.

Frontend: required, min='18', maxlength='8', pattern='(?=.*[A-Z]).{8,}'
Backend example:

pwd = request.form.get('password','')
if len(pwd) < 8 or not re.search(r'[A-Z]', pwd) or not re.search(r'[0-9]', pwd):
    flash('Weak password')

Haan, regex se password rules ho sakte hain.
Age 18-99, date >= today, slots <= 30 and > 0, confirm password == password, email '@' .
Duplicate username: User.query.filter_by(email=email).first() or unique=True catch IntegrityError.
Past date: if date < date.today(): reject. Negative slots: if slots < 0: reject; book pe available > 0 check.

SimpleVertical = same machine ko powerful banao. Horizontal = aur machines add karo.

Vertical (scale up): RAM/CPU badhao. Simple, lekin ek limit hai, downtime ho sakta hai, single point of failure.
Horizontal (scale out): 5 servers + load balancer. Sasta long-term, fault tolerant, lekin session/DB sharing sochna padta hai.

Example10k users aaye to Flask app ke 4 copies chalao nginx peeche, DB alag machine pe.

Thousands of requests on one machine: caching (Redis), DB indexes, gunicorn workers, phir horizontal.

SimpleVertical = same machine ko powerful banao. Horizontal = aur machines add karo.

Vertical (scale up): RAM/CPU badhao. Simple, lekin ek limit hai, downtime ho sakta hai, single point of failure.
Horizontal (scale out): 5 servers + load balancer. Sasta long-term, fault tolerant, lekin session/DB sharing sochna padta hai.

Example10k users aaye to Flask app ke 4 copies chalao nginx peeche, DB alag machine pe.

Thousands of requests on one machine: caching (Redis), DB indexes, gunicorn workers, phir horizontal.