Proctor Level1_145

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

SimpleGET data read/show karta hai (idempotent). POST create/submit karta hai (form).

Example

@app.route('/login', methods=['GET', 'POST'])
def login():
    if request.method == 'POST':
        # validate + session
        ...
    return render_template('login.html')

SimpleJinja2 Flask ka template engine — HTML ke andar {{ }} variables, {% %} logic.

Example

{% for lot in lots %}
  <li>{{ lot.name }} — {{ lot.spots }}</li>
{% else %}
  <p>No lots</p>
{% endfor %}

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')

SimpleLive Flask coding: chhota route likho, save, browser/curl se test. Syntax error terminal mein padho.

Example

@app.route('/ping')
def ping():
    return jsonify(ok=True)

@app.route('/even/<int:n>')
def even(n):
    return 'even' if n % 2 == 0 else 'odd'

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.

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.

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

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.

SimpleNaya Flask route: URL, method, auth if needed, query, jsonify. Postman pehle.

Examiner number/filter change easy rakhna. CORS. Frontend tabhi jab bole.

Status codes sahi. Password JSON mein nahi.

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

@app.route('/api/sum', methods=['POST'])
def sum_num():
    d = request.get_json()
    return jsonify(result=d['a'] + d['b'])

Project example: resources.py new Resource. Test Thunder. Optional Vue fetch.

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.

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

Example

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

SimpleLogin GET form dikhata hai, POST credentials check karke session set karta hai.

@app.route('/login', methods=['GET','POST'])
def login():
    if request.method == 'POST':
        u = User.query.filter_by(email=request.form.get('email')).first()
        if u and check_password_hash(u.password, request.form.get('password')):
            if getattr(u, 'blacklisted', False):
                flash('Blocked'); return redirect(url_for('login'))
            session['user_id'] = u.id
            session['role'] = u.role
            return redirect(url_for('dashboard'))
        flash('Invalid')
    return render_template('login.html')

Logout: session.clear(); redirect login. Incognito alag cookie jar — logged out dikhega.
Single login page: role se redirect alag dashboards.

SimplePOST nayi cheez create karta hai, PUT existing cheez ko replace/update karta hai.

POST /books → naya book add. Har baar naya ID banega. Idempotent nahi — 2 baar POST = 2 records.
PUT /books/5 → id=5 wale book ko poora update. Same PUT dubara bhejo to same result (idempotent).

PUT se create bhi ho sakta hai (agar ID client decide kare), lekin REST convention: create = POST, replace = PUT, partial = PATCH.

Example

@app.route('/user', methods=['POST'])          # register naya user
@app.route('/user/<int:id>', methods=['PUT'])  # poora profile replace

HTML <form> PUT nahi bhejta, isliye Flask apps mein edit pe bhi POST use hota hai. Examiner ko yeh reason clearly bolo.

SimpleHTTP methods batate hain request kya karna chahti hai. Common: GET POST PUT PATCH DELETE.

GETread/fetch. Safe, URL se. Page kholna, search.

POSTcreate/submit. Form, login.

PUTpoora replace/update. Idempotent.

PATCHpartial update.

DELETEhataana.

HEAD: sirf headers. OPTIONS: CORS preflight.

Flask: @app.route('/x', methods=['GET','POST'])
Agar methods na likho to default sirf GET.
HTML form native sirf GET/POST. PUT/DELETE JS/fetch ya hidden _method se.
GET se data fetch ho sakta hai, create nahi karna chahiye. POST se theoretically fetch ho sakta hai lekin cache/semantics galat.
DELETE fetch ke liye nahi. GET POST ka kaam officially nahi karta — side effects GET pe mat rakho.

Simple@app.route URL ko Python function se jodta hai. @ wala cheez decorator hai.

@app.route('/hello/<name>', methods=['GET'])
def hello(name):
    return f'Hello {name}'

Decorator function ko wrap karke extra behaviour deta hai (route register, login_required).
Endpoint generally function name. Path /hello/Ram.
<int:id> type converter — sirf integer. Bina converter string. ID chahiye to int safer.
methods=['POST'] only POST. Default GET.
functools.wraps custom decorator mein original function name/docs preserve karta hai.

Simpleurl_for sirf URL string banata hai, redirect us URL pe browser ko bhejta hai.

url_for('home') → '/home' (function name se URL nikalta hai)
redirect(url_for('home')) → browser ko /home pe le jaata hai

Example

return redirect(url_for('dashboard'))  # sahi
return redirect('/dashboard')         # hardcode, route change pe toot jaayega

Agar redirect se url_for hata do to khud path string dena padega: redirect('/dashboard').
Agar url_for('home') ko url_for('home_page') kar do aur home_page naam ka function nahi hai to BuildError aayega.

url_for ko function ka naam chahiye, URL path nahi.

SimpleUserMixin Flask-Login ko batata hai user object kaise treat karna hai (is_authenticated, get_id).

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)

current_user proxy logged-in user. Initialize: login_user(user) / user_loader callback.
Flask-WTF: Python classes se forms, CSRF, validators. RegisterForm forms.py mein.
fs_uniquifier Flask-Security mein token/session identity — email change pe sessions invalidate.
enctype='multipart/form-data' file upload pe zaroori. request.files.get('resume').

SimpleAPI = Application Programming Interface — do systems predefined rules se baat karti hain. REST API HTTP + JSON use karti hai.

Controller/route HTML bhi return kar sakta hai. REST API generally JSON return karti hai, frontend alag ho (Vue/Postman).

Example

@app.route('/api/users/<int:id>')
def get_user(id):
    u = User.query.get_or_404(id)
    return jsonify(id=u.id, name=u.name)

MAD1 HTML apps mein 'API' kabhi-kabhi routes ko hi keh dete hain. Agar Vue nahi to bolo: server-rendered Flask, JSON APIs optional.
Boolean return: technically jsonify(True) ho sakta hai, lekin meaningful JSON object better. Flask view None return kare to error.
Test: Postman se GET/POST.
Parsing: request.get_json() body se, request.args query se.

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).

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).

SimpleOOP = objects + classes. Inheritance child parent ke fields/methods reuse karta hai.

class User(db.Model): ...
class Admin(User): ...  # model inheritance (joiner ya single table)

Models inherit db.Model se taaki query/columns milen.

@staticmethod: self nahi, utility. isinstance(obj, User) type check.

MAD1 models classes hain, routes functions — mix of OOP + procedural.

SimpleJinja2 Flask ka template engine hai. HTML ke andar Python-jaisa data print/loop/if kar sakte ho.

Bina Jinja har user ke liye alag HTML file. Jinja se ek template + data.

{{ user.name }} print, {% for x in items %} loop, {% if %} condition, {% extends %} layout.

Example routereturn render_template('dash.html', treks=treks)

dash.html: {% for t in treks %}<li>{{ t.name }}</li>{% endfor %}

HTML files templates/ folder mein isliye kyunki Flask default wahan dhundhta hai. render_template Jinja ko run karta hai.
Boolean Jinja handle karta hai: {% if user.is_admin %}.

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.

SimpleStatus code number batata hai request ka result.

200 OK — success, page/data mil gaya.
201 Created — POST se naya resource.
302/303 Found/See Other — redirect (login ke baad).
304 Not Modified — cache use karo.
400 Bad Request — galat input.
401 Unauthorized — login nahi (ironically authentication missing).
403 Forbidden — login hai, permission nahi.
404 Not Found — route/record nahi.
500 Internal Server Error — server crash (DB error, NoneType). debug=True pe traceback.
501 Not Implemented — method server nahi sambhalta.

abort(404) Flask mein. get_or_404(id) record na ho to 404.
User ID GET pe exist na kare to 404 return karo, 500 nahi.

SimpleFlask default port 5000. Change: app.run(port=8000) ya env PORT, ya flask run --port 8000.

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0', port=8000)

Do apps ek saath: alag ports. Occupied port: error, doosra number try.

SimpleLive CSS/Vue: sabse chhota change jo dikhe. Logic/API mat todo unless poochhein.

Inspect element se class dhoondo. btn-success, navbar bottom fixed, center flex.

Save, refresh, dikhao. Break mat karo layout poora.

Example

<button class="btn btn-success">Login</button>
nav { position: fixed; bottom: 0; width: 100%; }
.wrap { min-height: 100vh; display: flex; align-items: center; justify-content: center; }

Project example: Jo button/navbar poocha usi file (Navbar.vue / App.vue / css).

Viva tipDevTools se element inspect. Logic/API mat todo unless poochhein.

SimpleNaya Flask route: URL, method, auth if needed, query, jsonify. Postman pehle.

Examiner number/filter change easy rakhna. CORS. Frontend tabhi jab bole.

Status codes sahi. Password JSON mein nahi.

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

@app.route('/api/sum', methods=['POST'])
def sum_num():
    d = request.get_json()
    return jsonify(result=d['a'] + d['b'])

Project example: resources.py new Resource. Test Thunder. Optional Vue fetch.

Simpleflask run --port 8000. Update axios baseURL CORS.

Change from 5000 to 8000.

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: Demo both.

Project example: Demo both.

SimpleClassic cron seconds nahi samajhta. Celery schedule=10.0 se seconds.

Examiner trap. Har 10s: schedule=10.0 ya timedelta(seconds=10).
Crontab fields mein seconds nahi.

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: Agar demo chahiye jaldi, har minute crontab better than 10s spam.

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.

SimpleCrontab 5 boxes: minute hour day-of-month month day-of-week.

crontab(hour=18, minute=0) roz 6pm. day_of_month=1 monthly. minute='*/1' har minute test.

Standard cron seconds support nahi. Examiner 'every 10 seconds' bole to schedule=10.0.

Beat process isi dict ko padhti hai. Edit ke baad beat restart.

Example

from celery.schedules import crontab
crontab(hour=18, minute=0)
crontab(minute='*/1')
crontab(day_of_month=1, hour=9, minute=0)

Project example: daily 18:00, monthly 1st 09:00. Viva mein dono 17:20 karke live dikhaya.

Viva tipStandard cron seconds support nahi karta. Har 10 sec ke liye Celery schedule=10.0 use karo.

SimpleRedis. Alternative RabbitMQ. Course Redis because cache bhi.

Between Flask client and Celery worker.

Celery Python ka distributed task queue — HTTP request ko 10s email/CSV ke liye mat rokna.

Flow: Flask .delay() → Redis broker → Worker execute. Beat alag process hai (clock): crontab padhke due time pe queue mein daalta hai. Beat khud mail nahi bhejta; Worker haath hai.

MAD2 typical: daily reminder (Beat), monthly report (Beat), user Export CSV (button, Beat nahi). JS async/await browser event loop hai, Celery server-side process — mix mat karo.

Demo: tin terminals — redis-server, celery worker, celery beat — plus Flask. MailHog :8025 inbox. Result backend se task SUCCESS poll optional.

Project example: broker_url redis://localhost:6379/0

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.

SimpleWebhook = woh tumhe call karta hai. API = tum unhe call karte ho.

Payment success pe Stripe tumhare /webhooks/payment pe POST. Tum poll nahi karte.

API pull, webhook push. WebSocket dono taraf live connection. SSE server→client stream.

MAD2 mostly REST APIs. Webhook theory + example kaafi. Verify signature production mein.

Example

@app.route('/webhooks/payment', methods=['POST'])
def hook():
    event = request.json
    ...

Project example: Agar implement nahi: 'course REST. Webhook design: POST /webhooks/booking-paid'.

Viva tipAPI pull, webhook push. WebSocket dono taraf live. SSE server → client stream.

SimpleCandidate key koi bhi unique ID (email, id). PK unme se election jeetne wala.

Email candidate. Hum id PK rakhte hain kyunki email change ho sakta.

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: User: id PK, email unique candidate.

SimpleCandidate key koi bhi unique ID (email, id). PK unme se election jeetne wala.

Email candidate. Hum id PK rakhte hain kyunki email change ho sakta.

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: User: id PK, email unique candidate.

SimpleOOP child parent methods. db.Model inherit. Vue mixins/composables. Jinja extends MAD1 → Vue layout slots/router-view.

Show where used. Template inheritance Vue analogue Navbar+router-view.

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: class User(db.Model). App.vue layout.

Simple== value. is identity same object. Speed micro. None: is None.

Difference is and ==. Performance negligible vs correctness.

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 user is None. Don't is for strings.

SimpleDirectives Vue ke special attributes — HTML ko superpower.

v-if/else/show, v-for, v-bind (:), v-on (@), v-model, v-html (XSS), v-cloak, v-slot.

:src = v-bind:src. @click = v-on:click.

Custom directives bhi (v-focus) — course basics kaafi.

Example

<p v-if="ok">Yes</p>
<li v-for="u in users" :key="u.id">{{ u.name }}</li>
<input v-model="email">
<img :src="url">

Project example: List v-for :key. Form v-model. Admin v-if. Image :src.

Viva tip: src ke liye v-bind:src ka shorthand. @click = v-on:click.

Simplev-if ghar se nikaal deta hai (DOM se). v-show sirf light band karta hai (display:none).

v-if false → element exist hi nahi — costly create/destroy, lekin secret HTML DOM mein nahi.
v-show → hamesha DOM, CSS hide, toggle tez.

Rare / permission UI: v-if (admin panel). Dropdown bar-bar: v-show.

: shorthand v-bind ka, v-if ka nahi.

Example

<div v-if="isAdmin">Admin panel</div>
<div v-show="open">Dropdown</div>

Project example: Admin links v-if="role==='admin'". FAQ accordion v-show="open".

Viva tipSecurity ke liye sirf v-if kaafi nahi — API 403 bhi chahiye.

SimpleEvery protected route guaranteed. Readable. Forget if manual if.

Why token_required and role_required.

Authentication poochta hai "tu kaun hai?", Authorization poochta hai "tujhe yeh kaam karne ki permission hai?"

Authentication: login. Username + password hash check. Success pe JWT/session. Galat credentials = 401.
Authorization: uske baad role. Admin hi venue/lot delete kare, student nahi = 403 (logged in ho, allowed nahi).

MAD2: POST /api/login = authentication. @jwt_required identity. @roles_required('admin') ya Vue v-if="isAdmin" = authorization. Frontend hide sirf UX — asli deny backend pe.

Validation alag: form sahi bhara (email format, age 18+). Woh identity prove nahi karta. Password store hash (Werkzeug), JWT payload padha ja sakta hai isliye secret mat daalo.

Project example: Can't skip check.