FastAPI को PostgreSQL से जोड़ना

from sqlalchemy import create_engine

# For PostgreSQL, this would be:
# SQLALCHEMY_DATABASE_URL = "postgresql://user:password@localhost/dbname"
# For a runnable example, we'll use SQLite:
SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"

engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)

print("Engine created successfully!")

from sqlalchemy.orm import sessionmaker
from sqlalchemy import create_engine

# Using SQLite for a runnable example
SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"
engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)

SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

print("SessionLocal configured!")

from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

print("Declarative Base initialized.")

from sqlalchemy.orm import Session
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

# Assuming these are defined elsewhere or imported
SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"
engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

print("get_db dependency function defined.")

from fastapi import FastAPI, Depends
from sqlalchemy.orm import Session

# For this snippet, we'll use a mock get_db to make it runnable
class MockSession:
    def close(self): pass

def get_db_mock():
    yield MockSession()

app = FastAPI()

@app.get("/db-status")
def read_db_status(db: Session = Depends(get_db_mock)):
    # In a real app, 'db' would be your actual SQLAlchemy session
    return {"message": "Database session received!"}

print("FastAPI endpoint defined using DB dependency.")

from fastapi import FastAPI, Depends
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, Session
from sqlalchemy.ext.declarative import declarative_base
import uvicorn

# --- Database Configuration (for PostgreSQL, replace URL) ---
# For a runnable example, we'll use SQLite in-memory:
SQLALCHEMY_DATABASE_URL = "sqlite:///./sql_app.db"
# For PostgreSQL, it would be:
# SQLALCHEMY_DATABASE_URL = "postgresql://user:password@localhost/dbname"

engine = create_engine(
    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
)
SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
Base = declarative_base()

# --- Dependency to get DB session ---
def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

# --- FastAPI Application ---
app = FastAPI()

@app.get("/connect-test")
def connect_test(db: Session = Depends(get_db)):
    # We've successfully received a DB session 'db'
    # In a real app, you'd perform DB operations here.
    return {"status": "Connected to DB", "db_type": SQLALCHEMY_DATABASE_URL.split('://')[0]}

# To run this, save as 'main.py' and run 'uvicorn main:app --reload'
# if __name__ == "__main__":
#    uvicorn.run(app, host="0.0.0.0", port=8000)