Flask-Flask development guide and tools

Example

Define URL endpoints with decorators and access request data via the request object: ```python from flask import Flask, request, jsonify app = Flask(__name__) @app.route('/search') def search(): q = request.args.get('q', '') return jsonify({'query': q, 'count': 0}) ```

Scenario

Search or filter endpoints for a web UI: a frontend calls /search?q=term; Flask reads query parameters, performs the lookup, and returns JSON. Good for APIs, microservices, and simple web pages that must accept GET/POST with form data.

Example

Render HTML templates with Jinja2 variables and control structures: ```python from flask import render_template @app.route('/profile/<username>') def profile(username): user = get_user(username) return render_template('profile.html', user=user) ``` Template snippet (profile.html): ```html <h1>Welcome, {{ user.name }}</h1> {% if user.bio %}<p>{{ user.bio }}</p>{% endif %} ```

Scenario

Classic multi-page apps, CMS-like pages, emails or server-rendered SEO pages. Use Jinja2 templates to compose pages, reuse macros, and keep presentation separate from Python logic.

Example

Initialize extensions and register blueprints for a modular structure: ```python from flask import Flask from flask_sqlalchemy import SQLAlchemy from auth import auth_bp app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db' db = SQLAlchemy(app) app.register_blueprint(auth_bp, url_prefix='/auth') ```

Scenario

Start with a small app and grow it: use Flask-SQLAlchemy for DB models, Flask-Migrate for migrations, Flask-Login for auth, and blueprints to split the code into auth, api, admin modules. This supports building production services, microservices, and team collaboration while keeping components isolated and testable.