CS504070 - Homework 7: Multiple Parameter Types with Validation

cs504070-homework-7.md

CS504070 - Homework 7

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Exercise 1: API with Multiple Parameter Types

Task

1. Create a FastAPI application with an endpoint /items/{item_id} that:

   • Takes item_id as a path parameter (integer).
   • Accepts category as a query parameter (string, optional).
   • Accepts price as a request body parameter (float).
   • Uses Annotated for validation.

2. The API should:

   • Validate item_id to be a positive integer.
   • Ensure price is greater than zero.
   • Return a response containing the processed parameters.

Hints

• Use Annotated[int, (Field/Path)] for validation.
• Use BaseModel for request body validation.

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Exercise 2: API with a List Field

Task

1. Create a FastAPI endpoint /cart/ that accepts a request body representing a shopping cart.
2. The request body should contain:
   • user_id (integer, required)
   • items (list of strings, min 1 item)
3. Return the received data as a response.

Requirements

• user_id should be a positive integer.
• items should be a non-empty list.

Hints

• Use Annotated for validation.
• Use Field(min_items=1) to enforce at least one item.

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Exercise 3: Nested Model for Orders

Task

1. Extend the API by adding an /order/ endpoint that accepts nested models in the request body.
2. The request body should have:
   • customer_id (integer, positive)
   • order_items (list of order objects)
3. Each order object must contain:
   • product_id (integer, required)
   • quantity (integer, min 1)
   • price (float, must be positive)

Requirements

• Use Annotated for validation.
• Ensure order_items is a non-empty list.

Hints

• Define OrderItem as a separate BaseModel and use it inside the main model.

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Exercise 4: Nested Model with Validation & Optional Fields

Task

1. Create a /invoice/ endpoint that accepts a complex invoice request with optional fields.
2. The request body should include:
   • invoice_id (UUID)
   • customer_details (nested model with name, email)
   • products (list of nested models)
3. Each product object must have:
   • product_id (integer, required)
   • name (string, min 3 characters)
   • price (float, must be positive)
   • discount (optional, float, between 0-50%)
   • tags (optional, list of strings)

Requirements

• Use Optional for nullable fields. Refer to the typing.Optional of Python.
• Use confloat to limit discount percentage. Refer to the Constrained types of Pydantic.

Hints

• Utilize Annotated and Field for detailed validation.
• Use UUID for invoice_id. Refer to the UUID documentation.