FastAPI MVC CRUD Build Delete Route

Learning objective: By the end of this lesson, you will be able to implement the HTTP DELETE method to remove existing “tea” resources from a FastAPI project.

Introduction

The HTTP DELETE method is used to remove a resource from the server. In this lesson, you’ll use DELETE to remove a tea from your mock database in the FastAPI app.

Implement the DELETE method in FastAPI

Now, let’s implement the DELETE method in our controllers/teas.py file to allow us to delete a tea resource.

1. Open the controllers/teas.py file.

2. Add the following code to implement the DELETE method:

# teas.py

@router.delete("/teas/{tea_id}")
def delete_tea(tea_id: int):
    # Delete a tea by ID
    for tea in teas_db['teas']:
        if tea['id'] == tea_id:
            teas_db['teas'].remove(tea)  # Remove the tea from the database
            return {"message": f"Tea with ID {tea_id} has been deleted."}

    # If tea was not found, raise an error
    raise HTTPException(status_code=404, detail="Tea not found")

What is happening in this code?

• @router.delete("/teas/{tea_id}"): This decorator creates a new DELETE route at /teas/{tea_id}. The {tea_id} part is a URL parameter that identifies which tea to delete.

• tea_id: int: This part indicates that the URL parameter tea_id should be an integer, representing the ID of the tea to delete.

• teas_db['teas'].remove(tea): This line removes the tea from the mock database (teas_db) by identifying the tea and calling remove() to delete it.

Testing the DELETE method using FastAPI’s interactive documentation

FastAPI provides a built-in developer sandbox to test your API endpoints. You can use it to quickly try out your DELETE method without writing any client-side code.

1. Start your FastAPI server if it’s not already running:

pipenv run uvicorn main:app --reload

1. Open your browser and navigate to http://127.0.0.1:8000/docs.

   This is FastAPI’s interactive API documentation. You’ll see a list of all available endpoints, including the DELETE /api/teas/{tea_id} route.

2. Click on DELETE /api/teas/{tea_id} to expand it.

3. Click the Try it out button. You’ll see a field where you can input the tea_id to specify which tea you want to delete.

4. In the tea_id field, enter the ID of the tea you want to delete (ex: 1).

5. Click the Execute button. This sends the DELETE request to remove the tea with the specified ID.

   • You should see a response confirming the deletion, with a message like this:

{
  "message": "Tea with ID 1 has been deleted."
}

Verifying the deletion

1. After executing the DELETE request, navigate to http://127.0.0.1:8000/api/teas in your browser.

   • You should see that the tea with the specified tea_id is no longer in the list. For example, if you deleted tea with ID 1, the list should look like this:

{
  "teas": [
    { "id": 2, "name": "lemongrass", "in_stock": true, "rating": 3.8 },
    { "id": 3, "name": "matcha", "in_stock": false, "rating": 4.4 }
  ]
}

What’s Next?

You’ve successfully implemented the DELETE method to remove a tea. This completes the basic CRUD operations (Create, Read, Update, Delete) for managing tea resources in FastAPI.

Now that you’ve learned the full CRUD cycle, you can start using these skills to build more complex applications or improve your existing FastAPI projects.