Miguel's flask mega tutorial

Link

Notes

• flask:
  • Use url_for to build and reference URLs
  • app.before_request, app.after_request (after_request can be used to measure database query performance)
  • Rotating file handler
  • Don't use window.history.back in forms
  • Move logic away from views
  • Better return query objects than query results
  • Pagination (yield_per in sqlalchemy)
  • Unit test:
    • use a different test database
    • regression testing: write a test for every new bug
  • Debugging: pdb.set_trace()
• Jinja:
  • Global variables/utilities like config, g, session, url_for are available in Jinja templates
  • render_template can be used in rendering HTML email templates
• Useful plugins: coverage, cProfile, werkzeug profiler

Code snippets

• pass variable in URL:

  python @app.route('/index/<int:page>') def turnto(page):

• use include in control statements in Jinja:

  {% for post in posts %} {% include "post.html" %} {% endfor %}

• rollback when error occurred:

  python @app.errorhandler(500) def err500(): dbsession.rollback()

• Python's fake mail server: python -m smtpd -n -c DebuggingServer localhost:1025

• Asynchoronous decorator:

  ```python from threading import Thread from functools import wraps

  def async(f): @wraps(f) def wrapper(args, *kwargs): thr = Thread(target = f, args = args, kwargs = kwargs) thr.start() return wrapper ```

• Expose new global variables in Jinja:

  python app.jinja_env.globals['momentjs'] = momentjs