🌶️

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"

if __name__ == "__main__":
    app.run(debug=True)

@app.route("/user/<username>")
def user(username):
    return f"User: {username}"

@app.route("/post/<int:post_id>")
def post(post_id):
    return f"Post: {post_id}"

@app.route("/login", methods=["GET", "POST"])
def login():
    if request.method == "POST":
        return do_login()
    return show_form()

from flask import request

# Query params
q = request.args.get("q", "")

# Form data
name = request.form["name"]

# JSON
data = request.get_json()

# Files
file = request.files["file"]
file.save("uploads/" + file.filename)

# Headers
token = request.headers.get("Authorization")

from flask import jsonify, redirect, make_response

# JSON
return jsonify({"status": "ok"})

# Redirect
return redirect(url_for("index"))

# Custom response
resp = make_response("Hello")
resp.headers["X-Custom"] = "Header"
return resp

from flask import render_template

@app.route("/hello/<name>")
def hello(name):
    return render_template("hello.html", name=name)

{{ variable }}
{{ name|capitalize }}
{% if user %}...{% endif %}
{% for item in items %}...{% endfor %}
{% extends "base.html" %}
{% block content %}...{% endblock %}

from flask_sqlalchemy import SQLAlchemy

app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///app.db"
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True)
    email = db.Column(db.String(120))

# Create
user = User(username="john")
db.session.add(user)
db.session.commit()

# Read
User.query.all()
User.query.filter_by(username="john").first()
User.query.get(1)

# Update
user.email = "new@example.com"
db.session.commit()

# Delete
db.session.delete(user)
db.session.commit()

# blueprints/api.py
from flask import Blueprint

api = Blueprint("api", __name__, url_prefix="/api")

@api.route("/users")
def get_users():
    return jsonify(users)

# app.py
from blueprints.api import api
app.register_blueprint(api)