116 lines
4.1 KiB
Markdown
116 lines
4.1 KiB
Markdown
---
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title: Simplifying Drupal Migrations with xautoload
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date: '2016-05-03'
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tags:
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- autoloading
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- drupal
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- drupal-planet
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- drupal-7
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- php
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use: [posts]
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---
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{% block excerpt %}
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How to use the [xautoload][1] module to autoload migration classes within your Drupal 7 migration modules.
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{% endblock %}
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{% block content %}
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## What is xautoload?
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[xautoload][1] is a Drupal module that enables the autoloading of PHP classes, in the same way that you would do so in a [Composer][2] based project such as Drupal 8 or Symfony.
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It supports both the [PSR-0][3] and [PSR-4][4] standards, as well as providing a wildcard syntax for Drupal’s `file[]` syntax in .info files.
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To use it, download and enable it from Drupal.org as you would for any other module, and then add it as a dependency within your module. The xautoload project page suggests including a minimum version in this format:
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```language-ini
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dependencies[] = xautoload (>= 7.x-5.0)
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```
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This will ensure that the version of xautoload is 7.x-5.0 or newer.
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## How to use it
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### Wildcard syntax for .info files
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Here is an example .info file for a migrate module.
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```language-ini
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; foo_migrate.info
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name = Foo Migration
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core = 7.x
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package = Foo
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files[] = includes/user.inc
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files[] = includes/nodes/article.inc
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files[] = includes/nodes/page.inc
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```
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In this example, each custom migration class is stored in it’s own file within the `includes` directory, and each class needs to be loaded separately using the `files[] = filename` syntax.
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One thing that the xautoload module does to enable for the use of wildcards within this syntax. By using wildcards, the module file can be simplified as follows:
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```language-ini
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files[] = includes/**/*.inc
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```
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This will load any .inc files within the `includes` directory as well as any sub-directories, like 'node' in the original example.
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This means that any new migration classes that are added will be automatically loaded, so you don’t need to declare each include separately within foo_migrate.info again. The great thing about this approach is that it works with the existing directory and file structure.
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### Use the PSR-4 structure
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If you want to use the [PSR-4][4] approach, you can do that too.
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In order to do so, you’ll need to complete the following steps:
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1. Rename the `includes` directory to `src`.
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2. Ensure that there is one PHP class per file, and that the file extension is `.php` rather than `.inc`.
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3. Ensure that the name of the file matches the name of the class - `FooArticleNodeMigration` would be in a file called `FooArticleNodeMigration.php`.
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4. Add a namespace to each PHP file. This uses the same format as Drupal 8, including the machine name of the module. For example, `Drupal\foo_migrate`.
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* If the class is within a sub-directory, then this will also need to be included within the namespace - e.g. `Drupal\foo_migrate\Node`.
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* You’ll also need to import any class names that you are referencing, including class names that are you extending, by adding `use` statements at the top of the file. You may be able to prefix it with `\` instead (e.g. `\DrupalNode6Migration`), but I prefer to use imports.
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Now your class may look something like this:
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```language-php
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<?php
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namespace Drupal\foo_migrate\Node;
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use DrupalNode6Migration;
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class FooArticleNodeMigration extends DrupalNode6Migration {
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...
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}
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```
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With these steps completed, any imports within your .info file can be removed as they are no longer needed and any classes will be loaded automatically.
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Within `foo_migrate.migrate.inc`, I can now reference any class names using their full namespace:
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```language-php
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$node_arguments['ArticleNode'] = array(
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'class_name' => 'Drupal\foo_migrate\Node\FooArticleNodeMigration',
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'source_type' => 'story',
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'destination_type' => 'article',
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);
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```
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## Resources
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* [xautoload module][1]
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* [migrate module][5]
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* [migrate_d2d module][6]
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* [PSR-0][3]
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* [PSR-4][4]
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{% endblock %}
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[1]: https://www.drupal.org/project/xautoload
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[2]: http://getcomposer.org
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[3]: http://www.php-fig.org/psr/psr-0/
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[4]: http://www.php-fig.org/psr/psr-4/
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[5]: https://www.drupal.org/project/migrate
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[6]: https://www.drupal.org/project/migrate_d2d
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