Grav Lifecycle

It is often useful to know how Grav processes in order to fully understand how best to extend Grav via plugins. This is the Grav lifecycle:

index.php

  1. Check PHP version to ensure we're running at least version 5.5.9
  2. Class loader initialization
  3. Obtain Grav instances

    Grav.php

    1. No instance exists, so call load()
    2. Add grav
    3. Initialize the debugger and add it to debugger
    4. Register the log handler
    5. Register the error handler
    6. Add uri
    7. Add task
    8. Add events
    9. Add cache
    10. Add session
    11. Add plugins
    12. Add themes
    13. Add twig
    14. Add taxonomy
    15. Add language
    16. Add pages
    17. Add assets
    18. Add page
    19. Add output
    20. Add browser
    21. Add base_url_absolute
    22. Add base_url_relative
    23. Add base_url
    24. Register the stream handler
    25. Register the config handler
  4. call Grav::process()

    Grav.php

    1. Initialize the configuration
    2. Initialize the Session
    3. Initialize the Uri object
    4. Initialize the error handler
    5. Initialize the debugger
    6. Start output buffering
    7. Initialize the timezone
    8. Initialize the plugins
    9. Fire onPluginsInitialized event
    10. Initialize the theme
    11. Fire onThemeInitialized event
    12. Fire onTask[TASK] event
    13. Initialize assets
    14. Fire onAssetsInitialized event
    15. Initialize twig

      Twig.php

      1. Set Twig template paths based on configuration
      2. Handle language templates if available
      3. Fire onTwigTemplatePaths event
      4. Load Twig configuration and loader chain
      5. Fire onTwigInitialized event
      6. Load Twig extensions
      7. Fire onTwigExtensions event
      8. Set standard Twig variables (config, uri, taxonomy, assets, browser, etc)
    16. Initialize pages

      Pages.php

      1. Call buildPages()
      2. Check if cache is good
      3. If cache is good load pages date from cache
      4. If cache is not good call recurse()
      5. Fire onBuildPagesInitialized event in recurse()
      6. If a .md file is found:

        Page.php

        1. Call init() to load the file details
        2. Set the filePath, modified, id
        3. Call header() to initialize the header variables
        4. Call slug() to set the URL slug
        5. Call visible() to set visible state
        6. Set modularTwig() status based on if folder starts with _
      7. Fire onPageProcessed event
      8. If a folder found recurse() the children
      9. Fire onFolderProcessed event
      10. Call buildRoutes()
      11. Initialize taxonomy for all pages
      12. Build route table for fast lookup
    17. Fire onPagesInitialized event
    18. Fire onPageInitialized event
    19. Add the debugger CSS/JS to the assets
    20. Get Output with Twig's processSite() method

      Twig.php

      1. Fire onTwigSiteVariables event
      2. Get the page output
      3. Fire onTwigPageVariables, also called for each modular subpage
      4. If a page is not found or not routable, first fire the onPageFallBackUrl event to see if we have a fallback for a media asset and then fire onPageNotFound if not
      5. Set all Twig variables on the Twig object
      6. Set the template name based on file/header/extension information
      7. Call render() method
      8. Return resulting HTML
    21. Fire onOutputGenerated event
    22. Set the HTTP headers
    23. Echo the output
    24. Flush the output buffers to the page
    25. Fire onOutputRendered event
    26. Connection to client is closed
    27. Fire onShutdown event

Whenever a page has its content() method called, the following lifecycle occurs:

Page.php

  1. If content is NOT cached:
    1. Fire onPageContentRaw event
    2. Process the page according to Markdown and Twig settings. Fire onMarkdownInitialized event
    3. Fire onPageContentProcessed event
  2. Fire onPageContent event