# Emerging Patterns in obsidian-mcp-resources
## Refactoring History (R5.1 - Quality Review)
### Pattern: Resource Registry (Implemented)
After implementing 5 resources (3 static, 2 dynamic), we identified and refactored the growing if-else chain in the ReadResource handler.
**Solution: ResourceRegistry class**
- Centralized resource registration and lookup
- Supports both static and dynamic resources with pattern matching
- Eliminates if-else chains in favor of O(n) lookup
- Clean separation between resource definition and handler logic
**Key benefits:**
1. Easy to add new resources without modifying core logic
2. Testable in isolation
3. Supports dynamic URI patterns like `vault://note/{path}`
### Pattern: BaseResourceHandler (Implemented)
Common functionality was extracted into an abstract base class:
**Shared functionality:**
- Response formatting (JSON and text)
- ObsidianClient creation and caching
- Error handling (404 → "Resource not found" messages)
- Path extraction from URIs
**Benefits:**
1. DRY - no duplicate formatting code
2. Consistent error handling across all resources
3. Easy to add new resource types by extending base class
4. Testable common functionality
## Dynamic Resource URIs
### Pattern: Path Parameters in Resource URIs
With R4.1, we introduced the first dynamic resource URI pattern: `vault://note/{path}`
**Key implementation details:**
1. **URI Structure**: Use `{param}` notation to indicate dynamic parts
- Example: `vault://note/{path}` where `{path}` is replaced with actual note path
- In ListResources, show the template with placeholders
- In ReadResource, parse actual values from the URI
2. **URI Parsing**: Simple string manipulation for path extraction
```typescript
if (uri.startsWith('vault://note/')) {
const path = uri.substring('vault://note/'.length);
// Use path to fetch content
}
```
3. **Resource Listing**: Include dynamic resources as templates
```typescript
{
uri: 'vault://note/{path}',
name: 'Note',
description: 'Individual note by path (e.g., vault://note/Daily/2024-01-01.md)',
mimeType: 'text/markdown'
}
```
4. **Error Handling**: Provide specific error messages for dynamic resources
- For missing notes: `Note not found: ${path}` instead of generic `Resource not found: ${uri}`
### Future Patterns to Consider
As we add more dynamic resources (R4.2: folders, R6.1: daily notes, R6.2: tags), consider:
1. **Consistent URI parsing strategy** - Extract common URI parsing logic if patterns repeat
2. **Resource validation** - Validate dynamic parameters before fetching
3. **Resource discovery** - How to help users discover available dynamic resources
4. **Caching strategy** - Dynamic resources may benefit from caching with path-based keys
## Testing Patterns
### Pattern: Mock ObsidianClient in Resource Tests
For testing resources that need ObsidianClient:
1. Extend Server interface to include optional obsidianClient
2. Inject mock client in tests
3. Use production client creation as fallback
```typescript
interface ServerWithClient extends Server {
obsidianClient?: ObsidianClient;
}
function getObsidianClient(server: ServerWithClient): ObsidianClient {
if (server.obsidianClient) {
return server.obsidianClient;
}
// Create production client
}
```
This pattern allows clean testing without modifying production code paths.
