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Getting Started

Installation

pip install tiny-fastapi-di

uv add tiny-fastapi-di

pip install tiny-fastapi-di[pydantic]

uv add tiny-fastapi-di[pydantic]

Your First Dependency

from tiny_fastapi_di import Depends, empty_di_ctx

# Define a dependency
def get_database():
    return {"host": "localhost", "port": 5432}

# Use it in a function
async def get_users(db: dict = Depends(get_database)):
    return f"Fetching users from {db['host']}"

# Run it - one call handles everything
async def main():
    result = await empty_di_ctx.call_fn(get_users)
    print(result)  # "Fetching users from localhost"

Injecting Values

Inject values directly by parameter name:

async def process_request(request_id: int, user_id: int):
    return f"Processing request {request_id} for user {user_id}"

async def main():
    result = await empty_di_ctx.call_fn(
        process_request,
        request_id=123,
        user_id=456
    )
    print(result)  # "Processing request 123 for user 456"

Resource Cleanup

Dependencies that use yield are automatically cleaned up:

def get_db_connection():
    print("Opening connection")
    connection = connect()
    try:
        yield connection
    finally:
        print("Closing connection")
        connection.close()

async def query_users(db = Depends(get_db_connection)):
    return db.query("SELECT * FROM users")

# Cleanup runs automatically after call_fn returns
result = await empty_di_ctx.call_fn(query_users)

Next Steps