[Solved] How can you modify this class-based dependency to accept a dynamic parameter from the request query?class UserInfo: def __init__(self, user_id: int): self.user_id = user_id def __call__(self):... | FastAPI

FastAPI - Dependency Injection

How can you modify this class-based dependency to accept a dynamic parameter from the request query?

class UserInfo:
    def __init__(self, user_id: int):
        self.user_id = user_id
    def __call__(self):
        return f"User ID is {self.user_id}"

@app.get("/user")
async def user(info: str = Depends(UserInfo)):
    return {"info": info}

Choose the correct way to pass user_id from query parameters.

AUse __init__(self, user_id: int = Query(...)) and import Query

BAdd user_id parameter to __call__ method instead

CPass user_id directly in Depends(UserInfo(user_id))

DUse global variable for user_id inside UserInfo

Step-by-Step Solution

Solution:

Step 1: Understand how FastAPI injects parameters
FastAPI injects parameters into __init__ if they have default values with Query or Body.
Step 2: Use Query to declare user_id in __init__
Adding user_id: int = Query(...) in __init__ allows FastAPI to get it from query parameters.
Final Answer:
Use __init__(self, user_id: int = Query(...)) and import Query -> Option A
Quick Check:
Query param in __init__ = dynamic dependency [OK]

Quick Trick: Use Query in __init__ to get query params [OK]

Common Mistakes:

MISTAKES

Trying to pass parameters in __call__
Passing instance in Depends directly
Using global variables instead of parameters

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More FastAPI Quizzes

How can you modify this class-based dependency to accept a dynamic parameter from the request query?

Step 1: Understand how FastAPI injects parameters

Step 2: Use Query to declare user_id in init

Final Answer:

Quick Check:

Want More Practice?

How can you modify this class-based dependency to accept a dynamic parameter from the request query?

Step 1: Understand how FastAPI injects parameters

Step 2: Use Query to declare user_id in __init__

Final Answer:

Quick Check:

Want More Practice?

Step 2: Use Query to declare user_id in init