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API Reference

Key classes, methods, and constants in Canvas Override.

Classes

CanvasOverridePermissions

Namespace: Drupal\canvas_override

Provides dynamic per-bundle permissions.

Methods

perBundlePermissions(): array

Returns permission definitions for each Canvas Override-enabled content type. Iterates over all node types, skips types where canvas_override.enabled is FALSE, and returns an array keyed by permission machine name.

Return format:

[
  'use canvas override for article' => [
    'title' => t('Use Canvas Override for %type content', ['%type' => 'Article']),
    'description' => t('Edit per-content Canvas layouts on %type content.', ['%type' => 'Article']),
  ],
]

CanvasTabAccessCheck

Namespace: Drupal\canvas_override\Access

Route access check for Canvas Override routes.

Methods

access(AccountInterface $account, NodeInterface $node): AccessResultInterface

Returns AccessResult::allowed() when:

  1. The node's content type has Canvas Override enabled (third-party setting).
  2. The user has at least one of:
  3. administer canvas override
  4. use canvas override
  5. use canvas override for {bundle}

Returns AccessResult::neutral() otherwise.

Cache contexts: Caches per user permissions and node type entity.

CanvasOverrideComponentTreeLoader

Namespace: Drupal\canvas_override\Storage

Extends Canvas's ComponentTreeLoader to support per-content layouts.

Methods

getCanvasFieldName(FieldableEntityInterface $entity): ?string

For Canvas Override-enabled nodes, returns the component_tree field name. Falls back to parent behavior for other entities.

load(FieldableEntityInterface $entity): ComponentTreeItemList

Loads the component tree for an entity. For nodes with an empty canvas field (first editor open), copies the ContentTemplate default into the node's own field to avoid returning a dangling ComponentTreeItemList.

CanvasOverrideNodeViewBuilder

Namespace: Drupal\canvas_override\EntityHandlers

Extends Canvas's ContentTemplateAwareViewBuilder.

Methods

buildComponents(array &$build, array $entities, array $displays, string $view_mode): void

Splits entities into override and template groups:

  • Override entities: Nodes with non-empty field_canvas_layout. Rendered via the decorated view builder.
  • Template entities: Nodes without per-content layout. Rendered via parent class (ContentTemplate).

hasPerNodeOverride(FieldableEntityInterface $entity): bool

Returns TRUE if the entity has a non-empty field_canvas_layout.

CanvasOverrideConstraintValidator

Namespace: Drupal\canvas_override\Plugin\Validation\Constraint

Decorates Canvas's ComponentTreeMeetsRequirementsConstraintValidator.

Methods

validate(mixed $value, Constraint $constraint): void

For Canvas Override-enabled nodes, modifies the constraint to allow EntityField and HostEntityUrl prop sources (field linking). Delegates to the original validator for all other entities.

RestoreRequiredFieldsConstraintValidator

Namespace: Drupal\canvas_override\Plugin\Validation\Constraint

Validates and restores required fields during Canvas API requests.

Methods

validate(mixed $value, Constraint $constraint): void

For each required field (except title and field_canvas_layout):

  • If current value is empty but original has a value: restores from original.
  • If both are empty and a default value exists: uses the default.

Only runs on Canvas API routes for existing, Canvas Override-enabled nodes.

CanvasRedirectController

Namespace: Drupal\canvas_override\Controller

Methods

redirectToEditor(NodeInterface $node): TrustedRedirectResponse

Redirects to canvas/editor/node/{node_id}. Throws NotFoundHttpException if Canvas Override is not enabled on the node's content type.

CanvasResetController

Namespace: Drupal\canvas_override\Controller

Methods

reset(NodeInterface $node): RedirectResponse

Clears the field_canvas_layout field and saves the node. Redirects to the node canonical view with a success message. Throws NotFoundHttpException if Canvas Override is not enabled.

CanvasOverrideServiceProvider

Namespace: Drupal\canvas_override

Extends ServiceProviderBase.

Methods

alter(ContainerBuilder $container): void

Swaps Canvas's ComponentTreeLoader service class with CanvasOverrideComponentTreeLoader.

CanvasOverrideHooks

Namespace: Drupal\canvas_override\Hook

Contains module integration logic.

Static Methods

ensureCanvasField(string $bundle): void

Creates and configures the field_canvas_layout field on a content type. Creates field storage, field config, and view display settings.

Constants

Constant Value File
CANVAS_OVERRIDE_FIELD_NAME field_canvas_layout canvas_override.module

Routes

Route Path Controller
canvas_override.node.canvas /node/{node}/canvas CanvasRedirectController::redirectToEditor
canvas_override.node.canvas.reset /node/{node}/canvas/reset CanvasResetController::reset

Third-Party Settings

Setting Entity Key Values
Canvas Override enabled NodeType canvas_override.enabled TRUE / FALSE

Static Permissions

Defined in canvas_override.permissions.yml:

Machine Name Restricted Tab unlocked
administer canvas override Yes All three tabs
use canvas override No Canvas Override + Reset
edit canvas default template Yes Edit template
reset canvas layout No Reset

Dynamic permissions are generated by CanvasOverridePermissions::perBundlePermissions().

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