Building a REST API with FastAPI, Async SQLModel, and PostgreSQL

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.7+ based on standard Python type hints.

Async SQLModel is an asynchronous ORM (Object Relational Mapper) built on top of SQLAlchemy and Pydantic that allows you to interact with your database using Python types. PostgreSQL is a popular open-source relational database management system that is known for its reliability and performance.

In this article, we will walk through the process of building a REST API using FastAPI, Async SQLModel, and PostgreSQL.

Step 1: Setting up the environment

First, you will need to install FastAPI, Async SQLModel, and the asyncpg driver for PostgreSQL. You can do this using pip:

pip install fastapi[all] sqlalchemy databases asyncpg

Step 2: Creating the database model

Next, you will define your database model using SQLModel. Here is an example of a simple User model:

    
    from sqlmodel import SQLModel, Field

    class User(SQLModel, table=True):
        id: int = Field(primary_key=True)
        name: str
        email: str
    
    

Step 3: Creating the API with FastAPI

Now, you will create your API using FastAPI. Here is an example of a simple API endpoint for creating a new user:

    
    from fastapi import FastAPI
    from asyncorm import Database
    from models import User

    app = FastAPI()

    @app.post("/users/")
    async def create_user(user: User):
        db = Database("postgresql://user:password@localhost/dbname")
        await db.connect()
        await db.insert(user)
        await db.disconnect()
        return {"message": "User created successfully"}
    
    

Step 4: Running the API

Finally, you can run your API using the uvicorn server. Run the following command in your terminal:

uvicorn your_api_file:app --reload

Your API should now be up and running! You can test it using a tool like Postman or cURL.

Conclusion

Building a REST API with FastAPI, Async SQLModel, and PostgreSQL is a powerful and efficient way to create APIs with Python. By following the steps outlined in this article, you can quickly build a robust API that interacts with a PostgreSQL database asynchronously.