Create A Simple Todo List API Using FastAPI

To create a simple to-do list API using FastAPI, you can follow these steps:

1. Install FastAPI and uvicorn using pip:

FastAPI is a Python web framework for building APIs, and uvicorn is an ASGI server for running Python web applications. The pip command is used to install these packages.

pip install fastapi uvicorn

2. Create a new Python file and import the necessary FastAPI modules:

We import the FastAPI class from the fastapi module, and the BaseModel class from the pydantic module. BaseModel is used to define the structure of the to-do item.

from fastapi import FastAPI
from pydantic import BaseModel

3. Define a class to represent a to-do item using Pydantic's BaseModel class:

We define a TodoItem class that inherits from BaseModel. The class has two attributes: task, which is a string representing the task to be done, and completed, which is a boolean indicating whether the task has been completed or not. The completed attribute has a default value of False.

class TodoItem(BaseModel):
    task: str
    completed: bool = False

4. Create an instance of the FastAPI app:

We create an instance of the FastAPI class and store it in the app variable.

app = FastAPI()

5. Create an empty list to store the to-do items:

We create an empty list named todo_list that will be used to store the to-do items.

todo_list = []

6. Define a route to create a new to-do item:

We use the @app.post decorator to define a route that handles HTTP POST requests to the /todo/ endpoint. The create_todo_item function takes a single argument item of type TodoItem. The function appends the new to-do item to the todo_list and returns a JSON response with a success message.

@app.post("/todo/")
async def create_todo_item(item: TodoItem):
    todo_list.append(item)
    return {"message": "Todo item created successfully"}

7. Define a route to get all the to-do items:

We use the @app.get decorator to define a route that handles HTTP GET requests to the /todo/{item_index} endpoint. The get_todo_items function returns a JSON response with the entire todo_list.

@app.get("/todo/")
async def get_todo_items():
    return {"todo_list": todo_list}

8. Define a route to get a specific to-do item by its index in the list:

We use the @app.get decorator to define a route that handles HTTP GET requests to the /todo/{item_index} endpoint, where item_index is an integer representing the index of the to-do item in the todo_list. The get_todo_item function returns a JSON response with the to-do item at the specified index.

@app.get("/todo/{item_index}")
async def get_todo_item(item_index: int):
    return todo_list[item_index]

9. Define a route to update a specific to-do item:

We use the @app.put decorator to define a route that handles HTTP PUT requests to the /todo/{item_index} endpoint. The update_todo_item function takes two arguments: item_index, which is an integer representing the index of the to-do item to be updated, and item, which is an instance of TodoItem representing the updated to-do item. The function updates the to-do item at the specified index in the todo_list and returns a JSON response with a success message.

@app.put("/todo/{item_index}")
async def update_todo_item(item_index: int, item: TodoItem):
    todo_list[item_index] = item
    return {"message": "Todo item updated successfully"}

10. Define a route to delete a specific to-do item:

We use the @app.delete decorator to define a route that handles HTTP DELETE requests to the /todo/{item_index} endpoint. The delete_todo_item function takes a single argument item_index, which is an integer representing the index of the to-do item to be deleted. The function deletes the to-do item at the specified index from the todo_list and returns a JSON response with a success message.

@app.delete("/todo/{item_index}")
async def delete_todo_item(item_index: int):
    del todo_list[item_index]
    return {"message": "Todo item deleted successfully"}

11. Run the application using uvicorn:

Finally, we use the uvicorn command to run the application on a local server. We pass the name of the Python file and the name of the FastAPI instance (app) as arguments to the uvicorn.run function, along with other optional parameters like host and port. By default, the application will run on http://localhost:8000/.

uvicorn main:app --reload

This is a basic example of how to create a to-do list API using FastAPI. You can customize it further to meet your requirements.