Welcome to Drupal at your fingertips

A Drupal 9 and 10 developers quick code reference

by Selwyn Polit

Read it here

This repository contains the markdown files for the book as well as a Drupal installation complete with config files and database dumps. It also has some code that was used to check the accuracy of the book.

If you want to contribute, select the gh-pages branch from the branches button near the top of this page. You can then directly click the pencil button to edit (and automatically fork the repo).

Thanks for visiting and contributing.

TL;DR click here to contribute to the gh-pages branch

Some tips

Running drush on the host vs the container

The recommended way to use drush on a ddev project is to use ddev drush cr etc.

For my own convenience, I prefer to just use drush cr while in the directory for my project. This does require an installation of PHP 8.1, drush and the drush launcher. If you see errors when trying this, try editing your web/sites/default/settings.php (or web/sites/default/settings.local.php) by adding the putenv command below. This may help.

putenv("IS_DDEV_PROJECT=true");

Enable Twig debugging

When you want to do some debugging, this can be a really useful setting to enable. It will display the template names in the HTML source.

• Copy sites/example.settings.local.php to sites/default/settings.local.php
• Add this to the bottom of sites/default/settings.php:

if (file_exists($app_root . '/' . $site_path . '/settings.local.php')) {
  include $app_root . '/' . $site_path . '/settings.local.php';
}

NOTE: sites/default/settings.php references sites/default/settings.local.php, which references sites/development.services.yml

• Create a sites/development.services.yml, with the following contents:
• toggle the debug: false line to view templates being used for each element on site
• Run drush cr after modifying the file to have changes take effect
• Warning. Make sure your site is actually running before you make this change otherwise it will not run and make you very frustrated.

# Local development services.
#
# To activate this feature, follow the instructions at the top of the
# 'example.settings.local.php' file, which sits next to this file.
parameters:
  http.response.debug_cacheability_headers: true
  twig.config:
    # Twig debugging:
    #
    # When debugging is enabled:
    # - The markup of each Twig template is surrounded by HTML comments that
    #   contain theming information, such as template file name suggestions.
    # - Note that this debugging markup will cause automated tests that directly
    #   check rendered HTML to fail. When running automated tests, 'debug'
    #   should be set to FALSE.
    # - The dump() function can be used in Twig templates to output information
    #   about template variables.
    # - Twig templates are automatically recompiled whenever the source code
    #   changes (see auto_reload below).
    #
    # For more information about debugging Twig templates, see
    # https://www.drupal.org/node/1906392.
    #
    # Not recommended in production environments
    # @default false
    debug: false
    # Twig auto-reload:
    #
    # Automatically recompile Twig templates whenever the source code changes.
    # If you don't provide a value for auto_reload, it will be determined
    # based on the value of debug.
    #
    # Not recommended in production environments
    # @default null
    auto_reload: true
    # Twig cache:
    #
    # By default, Twig templates will be compiled and stored in the filesystem
    # to increase performance. Disabling the Twig cache will recompile the
    # templates from source each time they are used. In most cases the
    # auto_reload setting above should be enabled rather than disabling the
    # Twig cache.
    #
    # Not recommended in production environments
    # @default true
    cache: false

services:
  cache.backend.null:
    class: Drupal\Core\Cache\NullBackendFactory

DDEV usage

Frequently used DDEV commands to get you started

If you haven't used DDEV, you should be using it! It makes development soooo much nicer.

ddev start - start containers

ddev stop - stop containers, delete them and keep db intact

ddev restart - rebuild containers if changing configuration of ddev

ddev ssh - ssh into container

ddev composer <blah> - run composer in container e.g. composer install

ddev describe - show the sql connection ports etc. for connecting sequel pro

ddev list -A - list sites and urls

ddev export-db --f dbdump1.sql.gz - Backup the db often so you can recover in a pinch. I use dbdump1 and dbdump2 files so I have a way back to my previous db too.

ddev import-db --src=dbdump1.sql.gz - Restore the db quickly and painlessly

To Enable/disable Xdebug in ddev

Use these commands. be sure to disable after debugging because xdebug has a significant performance impact.

ddev xdebug on and ddev xdebug off

Set up this site on your local computer

• check out the repo
• cd d9book
• composer install - this requires composer 2.x installed
• ddev config - this requires ddev to be installed. Follow the default prompts
• ddev start - this starts the containers
• ddev import-db --src=dbdump2.sql.gz - import the database
• ddev drush cr - clear drupal cache
• ddev launch - start the site

Lando usage

Create a local instance in Lando with these commands.

git clone https://github.com/selwynpolit/d9book
cd d9book/
lando start
lando composer install
lando drush site:install --db-url=mysql://drupal9:drupal9@database/drupal9 -y
lando db-import dbdump2.sql.gz
lando drush cache:rebuild
lando drush uli -l https://d9book.lndo.site

Troubleshooting

Containers won't start

ddev stop --remove-data --omit-snapshot - if db corrupt and containers won’t start. Follow this up with ddev start. You may also have to restart docker.