Troubleshooting
Common issues and their solutions when working with Plutonium.
Resource Class Detection
"Failed to determine the resource class" Error
Error messages:
NameError: Failed to determine the resource class for MyPortal::PostMetadataController.
Rails singularized "PostMetadata" to "PostMetadatum", but "PostMetadata" exists.
Add an inflection rule to config/initializers/inflections.rb.or:
NameError: Failed to determine the resource class.
Please call `controller_for(MyResource)` in MyPortal::MyResourceController.Cause: Plutonium infers the resource class from the controller name by singularizing it. For resources with names that don't follow standard Rails pluralization (like PostMetadata), Rails may singularize incorrectly (PostMetadata → PostMetadatum). Plutonium detects this and provides a helpful error message.
Solution: Add a custom inflection rule in config/initializers/inflections.rb:
ActiveSupport::Inflector.inflections(:en) do |inflect|
# Preserve "Metadata" when singularizing (e.g., PostMetadata stays PostMetadata)
inflect.singular(/(M)etadata$/i, '\1etadata')
endThis ensures Rails correctly handles the singularization throughout your application, including:
- Controller to model resolution
- Route generation
- Association lookups
Alternative: If you can't modify inflections, explicitly set the resource class in your controller:
class MyPortal::PostMetadataController < MyPortal::ResourceController
controller_for Blogging::PostMetadata
endCommon Words Needing Inflection Rules
| Word | Without Rule | With Rule | Inflection |
|---|---|---|---|
| Metadata | PostMetadatum | PostMetadata | inflect.singular(/(M)etadata$/i, '\1etadata') |
| Media | PostMedium | PostMedia | inflect.singular(/(M)edia$/i, '\1edia') |
| Data | PostDatum | PostData | inflect.singular(/(D)ata$/i, '\1ata') |
| Criteria | SearchCriterium | SearchCriteria | inflect.singular(/(C)riteria$/i, '\1riteria') |
URL Generation
Wrong URLs for Nested Resources
Symptom: URLs for nested resources include unexpected IDs or route to the wrong path.
Cause: Rails "param recall" fills in missing parameters from the current request when generating URLs. This can cause issues when both top-level and nested routes exist for the same resource.
Solution: Plutonium handles this automatically by using named route helpers for nested resources. Ensure you're using resource_url_for instead of url_for:
# Good - uses Plutonium's smart URL generation
resource_url_for(@comment, parent: @post)
# May have issues with param recall
url_for(controller: 'comments', action: 'show', id: @comment.id)Need More Help?
If you encounter an issue not covered here, please open an issue on GitHub.