chg: refactor KnowledgeGraph class into smaller, testable components

[gesinn-it-gea]

The KnowledgeGraph class has grown very large, making it difficult to maintain and test.

Proposed refactor:

• Split semantic data retrieval into a dedicated service/class.
• Move parser functions into a separate handler.
• Isolate WikiPage and category operations into helper classes.
• Ensure backward compatibility with existing hooks and JS integration.

Benefits: improved testability, readability, and maintainability.

[gesinn-it-gea]

Suggested Refactor – KnowledgeGraph Extension

1. Semantic Data Service

Class Name: KnowledgeGraphSemanticService
Responsibility:

• Fetch and normalize Semantic MediaWiki data.
• Methods:
  • setSemanticDataFromApi(Title $title, array $onlyProperties, int $depth, int $maxDepth)
  • getSubjectsByProperty(string $property, int $limit, int $offset, ?string $targetValue)
  • getAllPropertiesForNode(string $nodeTitleText)
• Optional: track relationsSeen internally.

---

2. Parser Function Handler

Class Name: KnowledgeGraphParserHandler
Responsibility:

• Handle the parser function #knowledgegraph.
• Parse parameters and apply defaults.
• Orchestrate fetching semantic data and preparing $graphs array.
• Methods:
  • parserFunctionKnowledgeGraph(Parser $parser, ...$argv)
  • parseParameters(array $parameters, array $defaultParameters)
  • applyDefaultParams(array $defaultParams, array $params)

---

3. WikiPage & Category Utilities

Class Name: KnowledgeGraphWikiUtils
Responsibility:

• Provide helper functions for working with pages and categories.
• Methods:
  • getWikiPage(Title $title)
  • getWikipageContent(Title $title)
  • articlesInCategories(string $category, int $limit, int $offset)

---

4. JS/Output Integration / Hooks

Class Name: KnowledgeGraphHooks (or keep as main KnowledgeGraph entry point)
Responsibility:

• Minimal hooks for integrating data with MediaWiki output.
• Methods:
  • onBeforePageDisplay(OutputPage $out, Skin $skin)
  • onSidebarBeforeOutput(Skin $skin, array &$sidebar)
  • onOutputPageParserOutput(OutputPage $out, ParserOutput $parserOutput)

---

5. Optional – Relations Manager

Class Name: KnowledgeGraphRelationsTracker
Responsibility:

• Encapsulate tracking of processed graph relations (relationsSeen)
• Simplifies testing and avoids static state in service classes.

[gesinn-it-gea]

@thomas-topway-it @paladox is this something you can help with?