FASTAPI Build API + Pydantic + Annotations + Pytest

Fastapi is the python webframe work used to develop the microservice apis rapidly. Its build based on starlette restapi architecture. Features of this framework are Automatic Document Generation, Validations , Security and Authentications, Dependency Injections and Supports Modern Python Types.

In this guide you will learn about how to develop basic apis ,run the application, request validations of api , annotations.

Run the application

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Installation and run a standard FastAPI application using uvicorn. It will also explain the different uvicorn arguments that can be used to control the behavior of your FastAPI application.

Step 1: Install FastAPI and Uvicorn

To get started, you need to install FastAPI and an ASGI server like uvicorn. You can install them using pip:

pip install fastapi
pip install "uvicorn[standard]"

step 2: Clone the application

git clone https://github.com/python-dev-bsram/fastapi-code.git

step3: Run the app using uvicorn

To run the FastAPI application, use uvicorn with the Python file (without the .py extension) followed by the app instance. For example:

# change the directory
cd /fastapi-annotation 

uvicorn main:app --reload

• main: The name of the Python file (without .py).
• app: The FastAPI application instance.
• --reload: Automatically reload the server when code changes (useful for development).

Uvicorn Arguments and Options

--host

By default, it runs on 127.0.0.1 (localhost). Use 0.0.0.0 to make it accessible from any IP address.

uvicorn main:app --host 0.0.0.0

--port

Defines the port on which the server will run.

uvicorn main:app --port 8001

--reload

Enables auto-reloading of the server when the code is modified. This is especially useful in development mode.

uvicorn main:app --reload

--workers

Defines the number of worker processes to run. This is useful in production environments where you need more performance.

uvicorn main:app --workers 4

--log-level

Sets the logging level. Options include critical, error, warning, info, debug, and trace.

uvicorn main:app --log-level debug

--limit-concurrency

Limits the maximum number of concurrent connections that Uvicorn will accept

uvicorn main:app --limit-concurrency 100

--timeout-keep-alive

Defines the timeout (in seconds) for keeping a connection alive

uvicorn main:app --timeout-keep-alive 60

--proxy-headers

Enables the handling of X-Forwarded-Proto and X-Forwarded-For headers, useful when running the app behind a proxy.

uvicorn main:app --proxy-headers

--env-file

Specifies a .env file to load environment variables from.

uvicorn main:app --env-file .env

--app-dir

Specifies a directory where the application module is located. This is useful if the app is not in the current working directory.

uvicorn app_name:app --app-dir /path/to/your/app

--ssl-keyfile and --ssl-certfile

Enable SSL (HTTPS) by specifying the key and certificate files.

uvicorn main:app --ssl-keyfile ./key.pem --ssl-certfile ./cert.pem