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D7 to D8 tutorial: pathinfo module
Last updated on
10 April 2024
This is a live step-by-step tutorial of my process of porting pathinfo module from Drupal 7.x to Drupal 8.x as part of the global sprint weekend, March 9th-10th, 2013.
The commit of Drupal 8 I was working against is:
* 957b556 - (HEAD, origin/HEAD, origin/8.x, 8.x) Issue #1932596 by ACF: Change site_name() into config in userpasswordreset.test and formtest. (4 hours ago)
Prerequisites
I installed a copy of Drupal 8 locally to test against. With that done:
- Start a new branch of my module:
$ git checkout -b 8.x-1.x - On my first push, create a new upstream branch
git push --set-upstream origin 8.x-1.x - Create a development release
Steps to upgrade
| Problem | Reason | Solution | Commit |
|---|---|---|---|
| Can't enable module. | .info files are now .info.yml files | Rename file and change to YAML format. | 1241617 and 4c2a072 |
| Using variable_* functions instead of CMI. | Site information variables converted to config system | How to upgrade variables into configuration | efbe1eb |
| Config form doesn't change variables stored via CMI. | system_settings_form() deprecated in favour of system_config_form() or \Drupal\system\SystemConfigFormBase | Refactor form to use system_config_form(). | b4c2b57 |
| Config form implemented procedurally. | While I used system_config_form() above, the preferred method is to extend \Drupal\system\SystemConfigFormBase. | Refactor hook_menu() definitions to a routing.yml, and a controller class. | e9c4566 |
| Some paths (like admin/structure/views) are not parsed correctly by pathinfo. | New Symfony-based routing system | Use "request" and "controller_resolver" Drupal services to find callback. | Can't get this to work. Pattern is
There's some issue with multiple requests on one page load. Will come back to this. |
| I want to use the new theming system, Twig. | Completely new theme/template system: Twig | Create a templates/pathinfo-served-by.html.twig file, move theme function to pre process. This can be useful: Theming Drupal 8 |
47086f2 |
| Picking this up again June 27 2013, at Drupal Dev Days. | |||
| config() function is going to be deprecated. | The config() function should be deprecated in favour of Drupal::config() | Replace all calls to config() with \Drupal::config(). | 363fb6d |
| The menu item is not shown at /admin/config. | Before I removed hook_menu() entirely - instead, hook_menu() deals with menus, while routes are handled by the Symfony-based routing system. | Restore hook_menu() to provide a menu UI for my module. | 4a44e54 |
| Nothing is output in the footer (this is the key functionality of the module). | hook_init() removed | Replace hook_init() with an event subscriber service. | 0e5fd56 |
Notes
- Use the Drupal 8 change records as your reference when upgrading.
- Now that Drupal runs on top of Symfony, a lot of core functionality is provided by services, which are managed by a Symfony Service Container. You can read about that in more detail in Change Notice: Use Dependency Injection to handle global PHP objects.
- The root Drupal class has a static method to help you access available services: Drupal::service()
- A handy way to see which services are available is
debug(drupal_container()->getServiceIds());
I have to admit, somewhat embarrassingly, that the module worked almost perfectly after my first commit above. Drupal 8 still has many Drupal 7 API calls intact, but I wanted to upgrade it to use D8 paradigms, so I kept going.
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