"""Dependencies for FastAPI routes."""
from typing import Annotated
from fastapi import Depends, HTTPException, Request
from db_context import MultiDatabaseContext, DatabaseContext
async def get_multi_db_context(request: Request) -> MultiDatabaseContext:
"""Get the MultiDatabaseContext from app state."""
multi_ctx = getattr(request.app.state, "multi_db_context", None)
if multi_ctx is None:
raise HTTPException(
status_code=503,
detail="Database context not initialized. Server may still be starting up."
)
return multi_ctx
def get_database_context(db_name: str, multi_ctx: MultiDatabaseContext) -> DatabaseContext:
"""Validate and return a specific database context."""
try:
return multi_ctx.get_database(db_name)
except ValueError as e:
available = ", ".join(multi_ctx.list_databases())
raise HTTPException(
status_code=404,
detail=f"{str(e)}. Available databases: {available}"
)
# Type aliases for dependency injection
MultiDBContextDep = Annotated[MultiDatabaseContext, Depends(get_multi_db_context)]
