Drupal7: JSON, hook_form_alter & hook_menu

This CodeLet demonstrates the use of hook_form_alter & hook_menu.
Using hook_form_alter, a text field is added to site information page. Once a API key is saved, the button has value 'Update configuration'
Using JSON menu, one can pull a node of type page, as JSON string.

Drupal: Commerce buy now

This CodeLet will redirect the user to checkout page when user clicks on 'Buy now' button on the product

Use the code and create a custom module

Make sure you keep the weight of the module high in "system" table