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basicmachines-co-basic-memory/src/basic_memory/services/link_resolver.py
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2025-01-31 16:38:06 -06:00

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4.4 KiB
Python

"""Service for resolving markdown links to permalinks."""
from typing import Optional, Tuple, List
from loguru import logger
from basic_memory.repository.entity_repository import EntityRepository
from basic_memory.services.search_service import SearchService
from basic_memory.models import Entity
from basic_memory.schemas.search import SearchQuery, SearchResult, SearchItemType
class LinkResolver:
"""Service for resolving markdown links to permalinks.
Uses a combination of exact matching and search-based resolution:
1. Try exact permalink match (fastest)
2. Try exact title match
3. Fall back to search for fuzzy matching
4. Generate new permalink if no match found
"""
def __init__(self, entity_repository: EntityRepository, search_service: SearchService):
"""Initialize with repositories."""
self.entity_repository = entity_repository
self.search_service = search_service
async def resolve_link(self, link_text: str, use_search: bool = True) -> Optional[Entity]:
"""Resolve a markdown link to a permalink."""
logger.debug(f"Resolving link: {link_text}")
# Clean link text and extract any alias
clean_text, alias = self._normalize_link_text(link_text)
# 1. Try exact permalink match first (most efficient)
entity = await self.entity_repository.get_by_permalink(clean_text)
if entity:
logger.debug(f"Found exact permalink match: {entity.permalink}")
return entity
# 2. Try exact title match
entity = await self.entity_repository.get_by_title(clean_text)
if entity:
logger.debug(f"Found title match: {entity.title}")
return entity
if use_search:
# 3. Fall back to search for fuzzy matching on title if specified
results = await self.search_service.search(
query=SearchQuery(title=clean_text, types=[SearchItemType.ENTITY]),
)
if results:
# Look for best match
best_match = self._select_best_match(clean_text, results)
logger.debug(f"Selected best match from {len(results)} results: {best_match.permalink}")
return await self.entity_repository.get_by_permalink(best_match.permalink)
# if we couldn't find anything then return None
return None
def _normalize_link_text(self, link_text: str) -> Tuple[str, Optional[str]]:
"""Normalize link text and extract alias if present.
Args:
link_text: Raw link text from markdown
Returns:
Tuple of (normalized_text, alias or None)
"""
# Strip whitespace
text = link_text.strip()
# Remove enclosing brackets if present
if text.startswith("[[") and text.endswith("]]"):
text = text[2:-2]
# Handle Obsidian-style aliases (format: [[actual|alias]])
alias = None
if "|" in text:
text, alias = text.split("|", 1)
text = text.strip()
alias = alias.strip()
return text, alias
def _select_best_match(self, search_text: str, results: List[SearchResult]) -> Entity:
"""Select best match from search results.
Uses multiple criteria:
1. Word matches in title field
2. Word matches in path
3. Overall search score
"""
if not results:
raise ValueError("Cannot select from empty results")
# Get search terms for matching
terms = search_text.lower().split()
# Score each result
scored_results = []
for result in results:
# Start with base score (lower is better)
score = result.score
# Parse path components
path_parts = result.permalink.lower().split("/")
last_part = path_parts[-1] if path_parts else ""
# Title word match boosts
term_matches = [term for term in terms if term in last_part]
if term_matches:
score *= 0.5 # Boost for each matching term
# Exact title match is best
if last_part == search_text.lower():
score *= 0.2
scored_results.append((score, result))
# Sort by score (lowest first) and return best
scored_results.sort(key=lambda x: x[0], reverse=True)
return scored_results[0][1]