How do you properly define a FastAPI dependency that takes a parameter and returns a callable dependency?

easy📝 Syntax Q3 of 15

FastAPI - Dependency Injection

ADefine a function that returns another function which uses the parameter, then pass the outer function with the parameter to Depends.

BPass the parameter directly inside Depends without wrapping it in another function.

CUse a class with __call__ method but do not accept parameters in the constructor.

DDeclare the dependency function with default parameters and call it directly in the route.

Step-by-Step Solution

Solution:

Step 1: Define outer function with parameter
This function accepts the parameter you want to inject.
Step 2: Define inner function as actual dependency
This inner function uses the parameter and is returned by the outer function.
Step 3: Use Depends with the outer function called with the parameter
Pass Depends(get_dependency(param_value)) in the route.
Final Answer:
Define a function returning a function and pass the outer function with parameter to Depends. -> Option A
Quick Check:
Dependency with parameters requires a factory function [OK]

Quick Trick: Use a factory function returning a dependency function [OK]

Common Mistakes:

MISTAKES

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