In this FastAPI tutorial, we will learn about Cookie parameters in FastAPI. Cookies are small pieces of data stored on the client’s browser that can be used to maintain session information, user preferences, or any other information that needs to be persisted across different requests.
FastAPI provides a convenient way to work with cookies using the Cookie parameter type. By using Cookie parameter type, you can easily access the values of cookies sent by the client in the request.
Let’s start by creating a new FastAPI app and defining a simple endpoint that reads a cookie named "user_id" from the client’s request.
from fastapi import FastAPI, Cookie
app = FastAPI()
@app.get("/get_user_id")
def get_user_id(user_id: str = Cookie(None)):
return {"user_id": user_id}In the above code, we have defined a new endpoint at /get_user_id that takes a single Cookie parameter named user_id. The parameter is of type str and has a default value of None.
When a client makes a request to this endpoint with a cookie named "user_id", the value of the cookie will be passed to the user_id parameter. If the cookie is not provided or has an empty value, the default value of None will be used.
To test this endpoint, you can use a tool like Postman to make a GET request to http://localhost:8000/get_user_id with a cookie named "user_id" and a value. The response should contain the user_id value from the cookie.
curl -X GET "http://localhost:8000/get_user_id" -H "Cookie: user_id=12345"Besides providing a default value for the Cookie parameter, you can also set a specific cookie name or specify other properties of the cookie. For example, you can set a maximum length for the cookie value, a default value, or a description for documentation purposes.
@app.get("/get_user_id")
def get_user_id(user_id: str = Cookie(None, max_length=50, description="The user ID")):
return {"user_id": user_id}In the above code, we have added additional properties to the user_id parameter. The max_length property limits the length of the cookie value to 50 characters, and the description property provides a description for the parameter.
You can also set additional properties such as secure, httponly, and expires to control other aspects of the cookie. For example, you can set the secure property to True to ensure that the cookie is only sent over HTTPS connections.
@app.get("/get_user_id")
def get_user_id(user_id: str = Cookie(None, secure=True)):
return {"user_id": user_id}In this tutorial, we have learned how to use Cookie parameters in FastAPI to work with cookies sent by the client in the request. By using Cookie parameters, you can easily access and manipulate cookie values in your FastAPI endpoints. You can also set various properties such as a default value, maximum length, and description for the cookie parameter to customize its behavior.
I hope this tutorial has helped you understand how to use Cookie parameters in FastAPI. If you have any questions or feedback, feel free to leave a comment below. Happy coding!
