Drupal 7 Line by Line Part 2 - drupal_bootstrap
This is the second part of my Drupal 7 Line by Line series. In the first part I walked through Drupal 7 index.php. As you recall there are only four lines of code and two function calls that display all the pages on your Drupal 7 site.
In this post I'll start walking through one of those functions: drupal_bootstrap(). If you recall from Part 1 I said this function is starts up (bootstraps) all of Drupal's mechanisms required to handle a page request. This is only part of the story and only half the truth. A more accurate description would be that it loads up only as much of Drupal's functionality a php script needs so that the php script can uses that functionality to do something.
When drupal_bootstrap is called from index.php it is passed a single argument: BOOTSTRAP_FULL. In order for index.php (a php script) to display a web page (what the script does) it needs Drupal to bootstrap all of its mechanisms (i.e. a full bootstrap).
Lets see what the phpDoc comment and function signature for drupal_bootstrap() have to say:
<br><?php<br>/**<br> * A string describing a phase of Drupal to load. Each phase adds to the<br> * previous one, so invoking a later phase automatically runs the earlier