SurfSense/surfsense_backend/app/retriver/documents_hybrid_search.py
2025-05-11 23:04:48 -07:00

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9.6 KiB
Python

class DocumentHybridSearchRetriever:
def __init__(self, db_session):
"""
Initialize the hybrid search retriever with a database session.
Args:
db_session: SQLAlchemy AsyncSession from FastAPI dependency injection
"""
self.db_session = db_session
async def vector_search(self, query_text: str, top_k: int, user_id: str, search_space_id: int = None) -> list:
"""
Perform vector similarity search on documents.
Args:
query_text: The search query text
top_k: Number of results to return
user_id: The ID of the user performing the search
search_space_id: Optional search space ID to filter results
Returns:
List of documents sorted by vector similarity
"""
from sqlalchemy import select, func
from sqlalchemy.orm import joinedload
from app.db import Document, SearchSpace
from app.config import config
# Get embedding for the query
embedding_model = config.embedding_model_instance
query_embedding = embedding_model.embed(query_text)
# Build the base query with user ownership check
query = (
select(Document)
.options(joinedload(Document.search_space))
.join(SearchSpace, Document.search_space_id == SearchSpace.id)
.where(SearchSpace.user_id == user_id)
)
# Add search space filter if provided
if search_space_id is not None:
query = query.where(Document.search_space_id == search_space_id)
# Add vector similarity ordering
query = (
query
.order_by(Document.embedding.op("<=>")(query_embedding))
.limit(top_k)
)
# Execute the query
result = await self.db_session.execute(query)
documents = result.scalars().all()
return documents
async def full_text_search(self, query_text: str, top_k: int, user_id: str, search_space_id: int = None) -> list:
"""
Perform full-text keyword search on documents.
Args:
query_text: The search query text
top_k: Number of results to return
user_id: The ID of the user performing the search
search_space_id: Optional search space ID to filter results
Returns:
List of documents sorted by text relevance
"""
from sqlalchemy import select, func, text
from sqlalchemy.orm import joinedload
from app.db import Document, SearchSpace
# Create tsvector and tsquery for PostgreSQL full-text search
tsvector = func.to_tsvector('english', Document.content)
tsquery = func.plainto_tsquery('english', query_text)
# Build the base query with user ownership check
query = (
select(Document)
.options(joinedload(Document.search_space))
.join(SearchSpace, Document.search_space_id == SearchSpace.id)
.where(SearchSpace.user_id == user_id)
.where(tsvector.op("@@")(tsquery)) # Only include results that match the query
)
# Add search space filter if provided
if search_space_id is not None:
query = query.where(Document.search_space_id == search_space_id)
# Add text search ranking
query = (
query
.order_by(func.ts_rank_cd(tsvector, tsquery).desc())
.limit(top_k)
)
# Execute the query
result = await self.db_session.execute(query)
documents = result.scalars().all()
return documents
async def hybrid_search(self, query_text: str, top_k: int, user_id: str, search_space_id: int = None, document_type: str = None) -> list:
"""
Combine vector similarity and full-text search results using Reciprocal Rank Fusion.
Args:
query_text: The search query text
top_k: Number of results to return
user_id: The ID of the user performing the search
search_space_id: Optional search space ID to filter results
document_type: Optional document type to filter results (e.g., "FILE", "CRAWLED_URL")
"""
from sqlalchemy import select, func, text
from sqlalchemy.orm import joinedload
from app.db import Document, SearchSpace, DocumentType
from app.config import config
# Get embedding for the query
embedding_model = config.embedding_model_instance
query_embedding = embedding_model.embed(query_text)
# Constants for RRF calculation
k = 60 # Constant for RRF calculation
n_results = top_k * 2 # Get more results for better fusion
# Create tsvector and tsquery for PostgreSQL full-text search
tsvector = func.to_tsvector('english', Document.content)
tsquery = func.plainto_tsquery('english', query_text)
# Base conditions for document filtering
base_conditions = [SearchSpace.user_id == user_id]
# Add search space filter if provided
if search_space_id is not None:
base_conditions.append(Document.search_space_id == search_space_id)
# Add document type filter if provided
if document_type is not None:
# Convert string to enum value if needed
if isinstance(document_type, str):
try:
doc_type_enum = DocumentType[document_type]
base_conditions.append(Document.document_type == doc_type_enum)
except KeyError:
# If the document type doesn't exist in the enum, return empty results
return []
else:
base_conditions.append(Document.document_type == document_type)
# CTE for semantic search with user ownership check
semantic_search_cte = (
select(
Document.id,
func.rank().over(order_by=Document.embedding.op("<=>")(query_embedding)).label("rank")
)
.join(SearchSpace, Document.search_space_id == SearchSpace.id)
.where(*base_conditions)
)
semantic_search_cte = (
semantic_search_cte
.order_by(Document.embedding.op("<=>")(query_embedding))
.limit(n_results)
.cte("semantic_search")
)
# CTE for keyword search with user ownership check
keyword_search_cte = (
select(
Document.id,
func.rank().over(order_by=func.ts_rank_cd(tsvector, tsquery).desc()).label("rank")
)
.join(SearchSpace, Document.search_space_id == SearchSpace.id)
.where(*base_conditions)
.where(tsvector.op("@@")(tsquery))
)
keyword_search_cte = (
keyword_search_cte
.order_by(func.ts_rank_cd(tsvector, tsquery).desc())
.limit(n_results)
.cte("keyword_search")
)
# Final combined query using a FULL OUTER JOIN with RRF scoring
final_query = (
select(
Document,
(
func.coalesce(1.0 / (k + semantic_search_cte.c.rank), 0.0) +
func.coalesce(1.0 / (k + keyword_search_cte.c.rank), 0.0)
).label("score")
)
.select_from(
semantic_search_cte.outerjoin(
keyword_search_cte,
semantic_search_cte.c.id == keyword_search_cte.c.id,
full=True
)
)
.join(
Document,
Document.id == func.coalesce(semantic_search_cte.c.id, keyword_search_cte.c.id)
)
.options(joinedload(Document.search_space))
.order_by(text("score DESC"))
.limit(top_k)
)
# Execute the query
result = await self.db_session.execute(final_query)
documents_with_scores = result.all()
# If no results were found, return an empty list
if not documents_with_scores:
return []
# Convert to serializable dictionaries
serialized_results = []
for document, score in documents_with_scores:
# Fetch associated chunks for this document
from sqlalchemy import select
from app.db import Chunk
chunks_query = select(Chunk).where(Chunk.document_id == document.id).order_by(Chunk.id)
chunks_result = await self.db_session.execute(chunks_query)
chunks = chunks_result.scalars().all()
# Concatenate chunks content
concatenated_chunks_content = " ".join([chunk.content for chunk in chunks]) if chunks else document.content
serialized_results.append({
"document_id": document.id,
"title": document.title,
"content": document.content,
"chunks_content": concatenated_chunks_content,
"document_type": document.document_type.value if hasattr(document, 'document_type') else None,
"metadata": document.document_metadata,
"score": float(score), # Ensure score is a Python float
"search_space_id": document.search_space_id
})
return serialized_results