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Route Parameters

When to Use

Use when routes need dynamic segments (e.g., node IDs, user IDs, custom identifiers). Parameters enable reusable routes for multiple entities or contexts.

Decision

Situation Choose Why
Numeric ID {param} with \d+ requirement Validates only digits
Entity object {entity_type} with type parameter Auto-loads entity, handles access
Alphanumeric slug {param} with [a-zA-Z0-9-]+ URL-safe characters only
Optional parameter Default value in controller YAML doesn't support optional segments

Pattern

# Numeric parameter with validation
my_module.item_view:
  path: '/items/{item_id}'
  defaults:
    _controller: '\Drupal\my_module\Controller\ItemController::view'
    _title_callback: '\Drupal\my_module\Controller\ItemController::getTitle'
  requirements:
    _permission: 'access content'
    item_id: '\d+'  # Only digits allowed
  options:
    parameters:
      item_id:
        type: integer

# Entity parameter (auto-loads node)
my_module.node_custom:
  path: '/node/{node}/custom-view'
  defaults:
    _controller: '\Drupal\my_module\Controller\NodeController::customView'
  requirements:
    _permission: 'access content'
    _entity_access: 'node.view'
  options:
    parameters:
      node:
        type: entity:node

Reference: core/modules/node/node.routing.yml

Common Mistakes

  • Wrong: Missing parameter validation in requirements → Right: Add regex validation for all parameters
  • Wrong: Not defining parameter type in options → Right: Specify type: integer or type: entity:node
  • Wrong: Using underscores in parameter names → Right: Use lowercase alphanumeric for consistency
  • Wrong: Forgetting _title_callback for dynamic titles → Right: Add callback for context-specific titles
  • Wrong: Missing entity access check → Right: Add _entity_access requirement

See Also