[Solved] What is the issue with this FastAPI endpoint for multiple file uploads?from fastapi import FastAPI, UploadFile from typing import List app = FastAPI() @app.post('/upload') async def upload(files:... | FastAPI

FastAPI - File Handling

What is the issue with this FastAPI endpoint for multiple file uploads?

from fastapi import FastAPI, UploadFile
from typing import List

app = FastAPI()

@app.post('/upload')
async def upload(files: List[UploadFile]):
    return {'count': len(files)}

AUsing async def instead of def

BMissing File(...) dependency in the parameter declaration

CNot importing File from fastapi

DReturning a dictionary instead of JSONResponse

Step-by-Step Solution

Solution:

Step 1: Check parameter declaration
The parameter files is typed as List[UploadFile] but lacks File(...) which is required to tell FastAPI to expect files.
Step 2: Understand File(...) role
File(...) is a special dependency that marks the parameter as a file upload field.
Final Answer:
Missing File(...) dependency in the parameter declaration -> Option B
Quick Check:
List[UploadFile] must be combined with File(...) [OK]

Quick Trick: Always add File(...) when using List[UploadFile] [OK]

Common Mistakes:

MISTAKES

Forgetting File(...) causes FastAPI to treat input as JSON
Assuming async def is incorrect (it's allowed)
Thinking return type must be JSONResponse explicitly

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More FastAPI Quizzes

What is the issue with this FastAPI endpoint for multiple file uploads?

Step 1: Check parameter declaration

Step 2: Understand File(...) role

Final Answer:

Quick Check:

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