Request & Response

from flask import request, jsonify

@app.route("/api/courses", methods=["GET"])
def get_courses():
    # Query parameters: /api/courses?level=beginner&limit=10
    level = request.args.get("level")
    limit = request.args.get("limit", 20, type=int)

    courses = Course.query.filter_by(level=level).limit(limit).all()
    return jsonify([c.to_dict() for c in courses])

@app.route("/api/courses", methods=["POST"])
def create_course():
    # JSON body
    data = request.get_json()
    if not data or "title" not in data:
        return jsonify({"error": "title required"}), 400

    # Form data (from HTML forms)
    name  = request.form.get("name")
    email = request.form.get("email")

    # Request metadata
    request.method        # "POST"
    request.url           # full URL
    request.headers       # all headers
    request.remote_addr   # client IP

from flask import jsonify, make_response, redirect, url_for

# JSON response (most common for APIs)
return jsonify({"courses": courses_list})

# With status code
return jsonify({"error": "Not found"}), 404
return jsonify({"id": new_id}), 201

# Custom response with headers
response = make_response(jsonify(data))
response.headers["X-Request-Id"] = request_id
response.status_code = 200
return response

# Redirect
return redirect(url_for("index"))
return redirect("https://nelsonlabs.dev", 301)

# Flash messages (shown in templates)
from flask import flash
flash("Course created successfully!", "success")
flash("Invalid email address", "error")