You want to create a FastAPI endpoint that lets users download a CSV file named data.csv stored in static/files/. The file path may not exist sometimes. Which is the best way to handle this safely?
hard🚀 Application Q15 of 15
FastAPI - File Handling
You want to create a FastAPI endpoint that lets users download a CSV file named data.csv stored in static/files/. The file path may not exist sometimes. Which is the best way to handle this safely?
AUse <code>FileResponse</code> with a try-except block to catch file not found errors and return 404
BReturn <code>FileResponse</code> directly without checking; client will get an error if file missing
CUse <code>StreamingResponse</code> without checking file existence
DSend the file content as a plain string response
Step-by-Step Solution
Solution:
Step 1: Understand file existence risk
Since the file may not exist, directly returning FileResponse risks server errors or confusing client errors.
Step 2: Implement error handling
Using a try-except block to catch FileNotFoundError and returning a 404 response is best practice for user-friendly error handling.
Final Answer:
Use FileResponse with a try-except block to catch file not found errors and return 404 -> Option A
Quick Check:
Check file existence and handle errors gracefully [OK]
Quick Trick:Always check file exists before FileResponse to avoid errors [OK]
Common Mistakes:
MISTAKES
Not handling missing files causing server errors
Using StreamingResponse without reason
Sending raw file content as string
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