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Python FastAPI

Basic API Setup with FastAPI

JARRETT RETZ March 24th, 2021 programming python fastapi api

    Introduction

    This article in the series will cover setting up a basic FastAPI project. The best tutorial for learning FastAPI is on their website. However, for the sake of continuity, I'll detail some steps here:

    • Setting up a virtual environment
    • Downloading necessary modules
    • Creating project files
    • Inserting starter code

    Virtual Environment

    First, create a new directory. Or, you can navigate (in a terminal or command shell) to the directory where you wish to create the project.

    I made a directory called fastapi_tutorial.

    Next, if you don't have it downloaded already, download virtualenv.

    $ pip3 install virtualenv

    This should install the package into your global Python interpreter or your current activated environment.

    Now, we can create a new virtual environment for the project.

    Why Create a Virtual Environment?

    We need a separate virtual environment for the project so that when we deploy, we know the minimum number of modules that are required to build the API.

    Creating a new environment will allow us to use the command pip freeze later to easily grab or package names and version.

    In the terminal run the command:

    $ virtualenv venv

    After the command is done, a new virtual environment folder is added to our project folder. The name of our new environment is venv.

    Finally, we need to activate the environment with:

    $ source venv/bin/activate

    Install Packages

    Next, we need to install the packages necessary to run FastAPI locally.

    $ pip3 install fastapi uvicorn

    The uvicorn package is for running the local server. Additionally, installing fastapi installed:

    • pydantic
    • starlette
    • typing-extensions

    Create the Server File

    Inside the root of the project, create the file main.py. Paste the below code into the file:

    from fastapi import FastAPI
    
    app = FastAPI()
    
    
    @app.get("/")
    async def root():
        return {"message": "Hello World"}

    In this file, we create our API and store it in the app variable.

    The "/" route is the index of our API. We add this route as the only route available. If you visit this route, you'll receive the return value, {"message": "Hello World"}.

    Start the Server

    With the virtual environment active, we can start the development server to run locally.

    In the terminal, in the root directory, run the command:

    uvicorn main:app --reload

    You'll see some output and the line:

    Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)

    Open up a browser and enter http://localhost:8000 for the URL.

    You should see our return value, {"message":"Hello World"}, and that means that we are successful!

    In the next article, we'll explore FastAPI more and build out the information for our routes. Thanks for reading!


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