[Solved] Given this code snippet, what will be printed when a request is made to /items/42?... Given this code snippet, what will be printed when a request is made to /items/42? | FastAPI

FastAPI - Dependency Injection

Given this code snippet, what will be printed when a request is made to /items/42?

from fastapi import FastAPI, Depends

app = FastAPI()

def common_dep():
    print("Global dependency called")

@app.get("/items/{item_id}")
def read_item(item_id: int, dep=Depends(common_dep)):
    return {"item_id": item_id}

ANo output printed because common_dep is not global

BGlobal dependency called printed once per request

CGlobal dependency called printed twice per request

DSyntaxError due to missing global dependency

Step-by-Step Solution

Solution:

Step 1: Check how common_dep is used
common_dep is used as a route dependency only on the read_item function, not as a global dependency.
Step 2: Understand when common_dep runs
It runs only when the /items/{item_id} route is called, printing the message once per request to that route.
Final Answer:
Global dependency called printed once per request -> Option B
Quick Check:
Route dependency prints only when route is called, not global [OK]

Quick Trick: Route dependencies run per route, not global unless set globally [OK]

Common Mistakes:

MISTAKES

Assuming common_dep is global when it's route-specific
Expecting multiple prints per request
Confusing global and route dependencies

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Given this code snippet, what will be printed when a request is made to /items/42?

Step 1: Check how common_dep is used

Step 2: Understand when common_dep runs

Final Answer:

Quick Check:

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