Flask code explainers

python

import hashlib
import json
from functools import wraps
from flask import g, request, jsonify, current_app

Building an idempotency decorator in Flask

idempotency decorators redis

Advanced 7 steps

python

from flask import Flask, request, redirect, current_app
from werkzeug.middleware.proxy_fix import ProxyFix
 
app = Flask(__name__)

Enforcing HTTPS behind a proxy in Flask

https middleware security-headers

Intermediate 7 steps

python

import functools
import time
 
from flask import current_app

Retrying deadlocked DB writes in Flask

decorators retry exponential-backoff

Intermediate 6 steps

python

import re
 
from flask_wtf import FlaskForm
from wtforms import StringField, TextAreaField, PasswordField

Cleaning form input with Flask-WTF filters

form validation input sanitization filters

Intermediate 8 steps

python

from datetime import datetime, timezone
 
from flask import abort
from sqlalchemy import Column, DateTime

Soft deletes with a custom SQLAlchemy Query in Flask

soft-delete mixin query-subclass

Advanced 7 steps

python

from flask import Blueprint, request, jsonify, abort
from sqlalchemy import update
 
from .models import db, Document

Optimistic locking in a Flask PATCH endpoint

optimistic-locking concurrency rest-api

Intermediate 7 steps

python

import os
import re
from flask import Blueprint, request, Response, abort

HTTP range requests for video streaming in Flask

http-range-requests streaming generators

Intermediate 8 steps

python

from io import BytesIO
from flask import Blueprint, abort, send_file
from reportlab.lib.pagesizes import LETTER
from reportlab.lib.units import inch

Streaming a generated PDF from a Flask route

pdf generation in-memory buffer file download

Intermediate 8 steps

python

import base64
import json
from flask import Blueprint, request, jsonify, url_for, abort
from sqlalchemy import and_, or_

Cursor pagination in a Flask API

cursor-pagination keyset-pagination rest-api

Advanced 9 steps

python

from flask import Flask, g, current_app
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

Scoped SQLAlchemy sessions in Flask

database session-management connection-pooling

Intermediate 6 steps

python

from flask import Flask, request, Response
from prometheus_client import Counter, Histogram, generate_latest, CONTENT_TYPE_LATEST
import time

Instrumenting a Flask app with Prometheus

metrics observability middleware

Intermediate 6 steps

python

from flask_wtf import FlaskForm
from wtforms import StringField, PasswordField, BooleanField
from wtforms.validators import (
    DataRequired,

Building a signup form with Flask-WTF

form validation declarative fields validators

Intermediate 7 steps

python

import logging
import uuid
from flask import Flask, request, g

Adding correlation IDs to Flask logs

logging request-lifecycle observability

Intermediate 7 steps

python

from datetime import datetime
 
from flask import Blueprint, abort, redirect, request
from sqlalchemy import func

Building a URL shortener redirect in Flask

routing url-shortener orm

Intermediate 6 steps

python

from functools import wraps
from flask import request, jsonify

A parameterized query-param decorator in Flask

decorators validation type-casting

Intermediate 8 steps

python

from flask import Blueprint, render_template, request, redirect, url_for, flash, abort
from .models import User, AuditLog
from .extensions import db
from .decorators import admin_required

Nesting Flask Blueprints for an admin panel

blueprints route-guards pagination

Intermediate 8 steps

python

import os
from uuid import uuid4
 
from flask import Blueprint, current_app, jsonify, request, url_for

How a Flask image upload endpoint works

file-upload validation image-processing

Intermediate 9 steps

python

from flask import g, session
 
from .extensions import cache
from .models import User

Injecting the current user in Flask templates

context-processor caching authentication

Intermediate 6 steps