Question

You want to save an uploaded file immediately and then process it in the background. Which FastAPI code snippet correctly implements this pattern?

Accepted Answer

async def upload(file: UploadFile, background_tasks: BackgroundTasks):
    contents = await file.read()
    with open(f"saved_{file.filename}", "wb") as f:
        f.write(contents)
    background_tasks.add_task(process_file, f"saved_{file.filename}")
    return {"message": "File saved and processing started"}

Answer

async def upload(file: UploadFile, background_tasks: BackgroundTasks):
    background_tasks.add_task(process_file, file)
    return {"message": "Processing started"}

Answer

async def upload(file: UploadFile):
    contents = await file.read()
    with open(f"saved_{file.filename}", "wb") as f:
        f.write(contents)
    process_file(f"saved_{file.filename}")
    return {"message": "File saved and processed"}

Answer

async def upload(file: UploadFile, background_tasks: BackgroundTasks):
    background_tasks.add_task(process_file, file.file.read())
    return {"message": "Processing started"}

You want to save an uploaded file immediately and then process it in the background. Which FastAPI code snippet correctly implements this pattern?

Step 1: Save file before background processing

Step 2: Add background task with saved filename

Final Answer:

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