Restful Content Negotiation

from flask import request, jsonify, make_response
import dicttoxml

@app.route('/users')
def get_users():
    # Determine response format
    accept = request.headers.get('Accept', 'application/json')

    users_data = [u.to_dict() for u in db.get_users()]

    if 'application/xml' in accept or 'text/xml' in accept:
        xml_response = dicttoxml.dicttoxml(users_data, custom_root='users')
        response = make_response(xml_response)
        response.headers['Content-Type'] = 'application/xml'
        return response

    # Default: JSON
    response = jsonify(users_data)
    response.headers['Content-Type'] = 'application/json'
    return response

# Vendor-specific media types
@app.route('/users/<int:id>')
def get_user(id):
    accept = request.headers.get('Accept', 'application/json')

    user = db.get_user(id)
    user_data = user.to_dict()

    if 'application/vnd.api.v2+json' in accept:
        # v2 format with additional fields
        user_data['full_name'] = f"{user.first_name} {user.last_name}"
        user_data['email'] = user.email
        content_type = 'application/vnd.api.v2+json'
    else:
        # v1 format
        user_data['name'] = user.first_name
        content_type = 'application/vnd.api.v1+json'

    response = jsonify(user_data)
    response.headers['Content-Type'] = f'{content_type}; charset=utf-8'
    response.headers['Vary'] = 'Accept'
    return response

// Express content negotiation
app.get('/api/users', (req, res) => {
  const users = db.getUsers();

  res.format({
    'application/json': () => {
      res.json(users);
    },
    'application/xml': () => {
      res.type('application/xml');
      res.send(xmlBuilder.buildObject({ users }));
    },
    'default': () => {
      res.status(406).json({ error: 'Not acceptable' });
    }
  });
});