Bulk-Resaving Elements

There may be times when you’ll need to make the same changes to multiple entries, like when you’re migrating content or establishing default values for newly-created fields.

Rather than applying these changes by hand, one at a time, you might be able to take advantage of Craft’s resave console commands or writing your own content migrations.

Resave Commands #

Craft ships with console commands you can run to do a variety of things, including a series of commands for resaving each major element type:

• resave/assets
• resave/categories
• resave/entries
• resave/matrix-blocks
• resave/tags
• resave/users

Triggering Resaves #

There are cases where simply triggering resaves can be useful, like when you’ve established a new Preparse field that determines its own value on save.

If we’ve added a Preparse field to an Assets field layout, for example, we could resave all assets by running this command from the terminal:

# save all assets
php craft resave/assets

This would load and resave all the assets across an install, but we could limit to those in a myImages volume:

# resave assets in `myImages` volume
php craft resave/assets --volume myImages

You might want to resave entries after changing a custom field’s search settings, specifically so that search indexes are updated. If we updated entries to make a field searchable, we would want to resave entries and pass the --update-search-index option:

# save entries and update the search index
php craft resave/entries --update-search-index

Resaving with Specific Field Values #

Craft 3.7.29 added powerful --set, --to, and --if-empty options that make it possible to specify content for individual fields and attributes.

Let’s pretend that we’ve added a new Plain Text field. Its field handle is myPlainTextField, and we’d like to set its value to whatever value is already stored in a separate fooField. We can do that like this:

# copy `fooField` value to `myPlainTextField`
php craft resave/entries --set myPlainTextField --to fooField

Using the --if-empty option, we can take care to save our new value only to fields that are already empty—leaving existing values untouched:

# copy `fooField` value to *empty* `myPlainTextField` fields
php craft resave/entries --set myPlainTextField --to fooField --if-empty

Then you might want to clear out the old fooField values:

# clear `fooField` value
php craft resave/entries --set fooField --to :empty:

The existing options for resave/entries still apply here. We won’t go through each one, but like the assets example above we could limit this resaving adventure only to entries in a blog section:

# copy `fooField` value to `myPlainTextField` in the `blog` section only
php craft resave/entries --set myPlainTextField --to fooField --section blog

Resaving with Computed Field Values #

We’ve used fixed strings as values in the examples above, but you can also use Twig or PHP arrow functions to compute the value to be saved at runtime.

Let’s say we want to resave entries and set our myPlainTextField value to the entry author’s name. We could do that thusly:

# set `myPlainTextField` to entry author’s name
php craft resave/entries --set myPlainTextField --to "={author.name}"

That "={author.name}" part is a Twig object template like you’d use for entry URI formats, Asset field subfolder paths and redirect params. It must start with = and is parsed like a full-blown Twig template.

You can similarly use PHP arrow functions:

# set `myPlainTextField` to entry author’s name
php craft resave/entries --set myPlainTextField --to "fn(\$entry) => \$entry->author->name"

You can use arrow functions to set values for relational fields. Here we can pass an array of IDs for an Entries field:

# have `myEntriesField` reference element IDs 1, 2, and 3
php craft resave/entries --set myEntriesField --to "fn(\$entry) => [1, 2, 3]"

Content Migrations #

The Craft CLI’s resave commands are great for relatively straightforward tasks, but you may want to consider using content migrations for more nuanced or intense modification of existing field data.

You’ll need to set up and write a content migration, but it can be more complex, checked into your git repository, and easily-executed in other environments.

To do the equivalent of the last arrow function example in a content migration:

1. Run php craft migrate/create my_resave_migration. This will generate a .php file in your project’s migrations/ directory.

2. Open that generated migration file and add the following to safeUp():

    $elementsService = Craft::$app->getElements();
    $entryQuery = \craft\elements\Entry::find();
   
    $elementsService->on(
        \craft\services\Elements::EVENT_BEFORE_RESAVE_ELEMENT,
        static function(\craft\events\BatchElementActionEvent $e) use ($entryQuery) {
            if ($e->query === $entryQuery) {
                $element = $e->element;
                $element->myPlainTextField = $element->author->name ?? null;
            }
        }
    );
   
    $elementsService->resaveElements(
        $entryQuery,
        true,
        true
    );
   

3. Run php craft migrate/up --content or from the control panel navigate to Utilities → Migrations and run your migration there.

You could introduce whatever logic you might need in your content migration, or even save elements individually rather than rely on the resaveElements() method.

Before saving an element, however, be sure to set its resaving property to true in order to keep its dateUpdated from being changed:

$elementsService = Craft::$app->getElements();
$entryQuery = \craft\elements\Entry::find();

foreach ($entryQuery->all() as $element) {
    $element->resaving = true;
    $element->myPlainTextField = $element->author->name ?? null;
    $elementsService->saveElement($element);
}