The Page Build Process

The Nestor system follows the same Page Build process for each requested page, however the final rendered page is determined by the Recipe and components associated with the page.

The Nestor Page Build Process Flow shows how each of the core engine classes, configuration files, hooks and page components interact to render the final page.

To follow the Page Build process flow:

  1. The lane on the far left, labeled “Initiate”, contains the major steps in the Page Build process. This lane roughly follows the code flow in initiate.php
  2. During execution of initiate.php, all of the major Core Engine classes are loaded and instantiated, and then added to the master $vce object. The master $vce class allows for ease of access to each of these objects from other components.
  3. All of the colored circles in the Initiate lane represent control passing to one of the Core Engine classes. When you see a colored circle, look for a corresponding colored circle across the top of the lanes. Each of these lanes represents the events in the __construct() method of the class.
  4. Follow the flow down the lane for each class to learn about its function. At the end of the lane flow, you’ll reach a second colored circle indicating that control is passed back to the Initiate process flow.
  5. In a few cases, control is passed back and forth between the Core Engine classes. This will be indicated by flow arrows crossing the lane boundaries.
  6. The squares colored light green represent Hooks. These are areas in the process where you can insert a call to a method in your custom Component. Refer to the Hooks Section for more information.

When the Page object is instantiated during Initiation it kicks off the most complex phases of the Page Build process. The intricate interaction between Page, other core Engine Classes, and page Components provides a rich opportunity to build custom code to affect the final rendered page. By design, the Page class calls into specific methods in each component it processes during Page Build. Also, there are many Hooks invoked during Page Build into which your custom Component can insert code.

Build Components Array Process

Since the components hold all of the information about how a page is built, it’s important to assemble an array that contains all of the components associated with the page under construction. This array includes the metadata that defines each component. A key piece of metadata is the page Recipe which is discovered and added to the global $page object during this process. Also, there is a parent-child-sibling hierarchy between Components that must be reflected in the array. In order to build out this multifarious component tree, there are many levels of recursion executed in the two Page methods involved in building out the array – get_components() and get_sub_components().

The Build Components Array process is documented in the Build Component Array Process flow chart, which not only shows the control flow between methods and classes, but also indicates where hooks are invoked in which you can insert your own custom methods.

Build Content Process

Once the full Component array has been populated, it’s time to build out the HTML content that is rendered on the final page. This process involves traversing the component array structure and comparing it to the page Recipe, component-by-component. Comparing the two allows the process to check for Role-based access as well as call specific methods in each component to determine what content should be written out to the page. There are opportunities for your custom component to stop the entire Page Build within this process if there are scenarios where it makes sense for your component to do so.

The Build Content process is documented in the Build Content Process flowchart, which not only shows the control flow between methods and classes, but also indicates where hooks are invoked in which you can insert your own custom methods.