Files
drb-core-server/app/internal/db_handler.py
2025-05-11 20:33:57 -04:00

252 lines
10 KiB
Python

import motor.motor_asyncio
import asyncio
from typing import Optional, Dict, Any, List
class MongoHandler:
"""
A basic asynchronous handler for MongoDB operations using motor.
Designed to be used with asyncio.
"""
def __init__(self, db_name: str, collection_name: str, mongo_uri: str = "mongodb://localhost:27017/"):
"""
Initializes the MongoDB handler.
Args:
db_name (str): The name of the database to connect to.
collection_name (str): The name of the collection to use.
mongo_uri (str): The MongoDB connection string URI.
Defaults to the standard local URI.
"""
self.mongo_uri = mongo_uri
self.db_name = db_name
self.collection_name = collection_name
self._client: Optional[motor.motor_asyncio.AsyncIOMotorClient] = None
self._db: Optional[motor.motor_asyncio.AsyncIOMotorDatabase] = None
self._collection: Optional[motor.motor_asyncio.AsyncIOMotorCollection] = None
async def connect(self):
"""Establishes an asynchronous connection to MongoDB."""
if self._client is None:
try:
self._client = motor.motor_asyncio.AsyncIOMotorClient(self.mongo_uri)
# The ismaster command is cheap and does not require auth.
# It is used to confirm that the client can connect to the deployment.
await self._client.admin.command('ismaster')
self._db = self._client[self.db_name]
self._collection = self._db[self.collection_name]
print(f"Connected to MongoDB: Database '{self.db_name}', Collection '{self.collection_name}'")
except Exception as e:
print(f"Failed to connect to MongoDB at {self.mongo_uri}: {e}")
self._client = None # Ensure client is None if connection fails
raise # Re-raise the exception after printing
async def close(self):
"""Closes the MongoDB connection."""
if self._client:
self._client.close()
self._client = None
self._db = None
self._collection = None
print("MongoDB connection closed.")
async def __aenter__(self):
"""Allows using the handler with async with."""
await self.connect()
return self
async def __aexit__(self, exc_type, exc_val, exc_tb):
"""Ensures the connection is closed when exiting async with."""
await self.close()
async def insert_one(self, document: Dict[str, Any]) -> Any:
"""
Inserts a single document into the collection.
Args:
document (Dict[str, Any]): The document to insert.
Returns:
Any: The result of the insert operation (InsertOneResult).
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
print(f"Inserting document into '{self.collection_name}'...")
result = await self._collection.insert_one(document)
print(f"Inserted document with ID: {result.inserted_id}")
return result
async def find_one(self, query: Dict[str, Any]) -> Optional[Dict[str, Any]]:
"""
Finds a single document matching the query.
Args:
query (Dict[str, Any]): The query document.
Returns:
Optional[Dict[str, Any]]: The found document, or None if not found.
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
print(f"Finding one document in '{self.collection_name}' with query: {query}")
document = await self._collection.find_one(query)
return document
async def find(self, query: Dict[str, Any] = None) -> List[Dict[str, Any]]:
"""
Finds multiple documents matching the query.
Args:
query (Dict[str, Any], optional): The query document. Defaults to None (find all).
Returns:
List[Dict[str, Any]]: A list of matching documents.
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
if query is None:
query = {}
print(f"Finding documents in '{self.collection_name}' with query: {query}")
# Use list comprehension to iterate through the cursor asynchronously
documents = [doc async for doc in self._collection.find(query)]
print(f"Found {len(documents)} documents.")
return documents
async def update_one(self, query: Dict[str, Any], update: Dict[str, Any], upsert: bool = False) -> Any:
"""
Updates a single document matching the query.
Args:
query (Dict[str, Any]): The query document.
update (Dict[str, Any]): The update operations to apply.
upsert (bool): If True, insert a new document if no match is found.
Returns:
Any: The result of the update operation (UpdateResult).
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
print(f"Updating one document in '{self.collection_name}' with query: {query}, update: {update}")
result = await self._collection.update_one(query, update, upsert=upsert)
print(f"Matched {result.matched_count}, Modified {result.modified_count}, Upserted ID: {result.upserted_id}")
return result
async def delete_one(self, query: Dict[str, Any]) -> Any:
"""
Deletes a single document matching the query.
Args:
query (Dict[str, Any]): The query document.
Returns:
Any: The result of the delete operation (DeleteResult).
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
print(f"Deleting one document from '{self.collection_name}' with query: {query}")
result = await self._collection.delete_one(query)
print(f"Deleted count: {result.deleted_count}")
return result
async def delete_many(self, query: Dict[str, Any]) -> Any:
"""
Deletes multiple documents matching the query.
Args:
query (Dict[str, Any]): The query document.
Returns:
Any: The result of the delete operation (DeleteResult).
"""
if self._collection is None:
raise RuntimeError("MongoDB connection not established. Call connect() first or use async with.")
print(f"Deleting many documents from '{self.collection_name}' with query: {query}")
result = await self._collection.delete_many(query)
print(f"Deleted count: {result.deleted_count}")
return result
# --- Example Usage ---
async def example_mongo_usage():
"""Demonstrates how to use the MongoHandler."""
# Ensure you have a MongoDB server running, default is localhost:27017
db_name = "radio_app_db"
collection_name = "channels"
# Using async with ensures the connection is closed automatically
async with MongoHandler(db_name, collection_name) as mongo:
# --- Insert Example ---
print("\n--- Inserting a document ---")
channel_data = {
"_id": "channel_3", # You can specify _id or let MongoDB generate one
"name": "Emergency Services",
"frequency_khz": 453000,
"location": "Countywide",
"avail_on_nodes": ["client-xyz987"],
"description": "Monitor for emergency broadcasts."
}
try:
insert_result = await mongo.insert_one(channel_data)
print(f"Insert successful: {insert_result.inserted_id}")
except Exception as e:
print(f"Insert failed: {e}")
# --- Find One Example ---
print("\n--- Finding one document ---")
query = {"_id": "channel_3"}
found_channel = await mongo.find_one(query)
if found_channel:
print("Found document:", found_channel)
else:
print("Document not found.")
# --- Find Many Example ---
print("\n--- Finding all documents ---")
all_channels = await mongo.find() # Empty query finds all
print("All documents:", all_channels)
# --- Update Example ---
print("\n--- Updating a document ---")
update_query = {"_id": "channel_3"}
update_data = {"$set": {"location": "Statewide", "avail_on_nodes": ["client-xyz987", "client-newnode1"]}}
update_result = await mongo.update_one(update_query, update_data)
print(f"Update successful: Matched {update_result.matched_count}, Modified {update_result.modified_count}")
print("\n--- Finding the updated document ---")
updated_channel = await mongo.find_one(update_query)
print("Updated document:", updated_channel)
# --- Delete Example ---
print("\n--- Deleting a document ---")
delete_query = {"_id": "channel_3"}
delete_result = await mongo.delete_one(delete_query)
print(f"Delete successful: Deleted count {delete_result.deleted_count}")
print("\n--- Verifying deletion ---")
deleted_channel = await mongo.find_one(delete_query)
if deleted_channel:
print("Document still found (deletion failed).")
else:
print("Document successfully deleted.")
# --- Insert another for delete_many example ---
temp_doc1 = {"_id": "temp_1", "tag": "temp"}
temp_doc2 = {"_id": "temp_2", "tag": "temp"}
await mongo.insert_one(temp_doc1)
await mongo.insert_one(temp_doc2)
# --- Delete Many Example ---
print("\n--- Deleting many documents ---")
delete_many_query = {"tag": "temp"}
delete_many_result = await mongo.delete_many(delete_many_query)
print(f"Delete many successful: Deleted count {delete_many_result.deleted_count}")
# To run the example usage:
# 1. Ensure you have a MongoDB server running locally on the default port (27017).
# 2. Save the code as mongodb_handler.py.
# 3. Run from your terminal: python -m asyncio mongodb_handler.py
if __name__ == "__main__":
# Running the example directly requires running within an asyncio loop
asyncio.run(example_mongo_usage())