Dati dei form e upload di file
Gestisca i dati dei form HTML tradizionali e implementi l'upload di file usando le funzionalità integrate di FastAPI.
Dati dei form e upload di file è una lezione FastAPI Backend Development Bootcamp gratuita su CoddyKit. Questa è la lezione 3 di 4. Puoi leggere la lezione completa qui gratuitamente — poi esercitati direttamente nel browser con un editor di codice integrato e un tutor IA disponibile 24/7. Fa parte del percorso di apprendimento FastAPI Backend Development Bootcamp, e i tuoi progressi si sincronizzano tra il web e l'app CoddyKit. Il corso FastAPI Backend Development Bootcamp include 4 lezioni in totale.
Parti di questa lezione non sono ancora state tradotte e vengono mostrate in inglese.
Form Data Basics
When you fill out a web form (like a login or registration page) and click "submit," the data you entered is often sent as form data.
This is a traditional way for browsers to send information to a server, different from sending JSON in a request body.
Form data can be sent in two main ways:
application/x-www-form-urlencoded: For simple key-value pairs.multipart/form-data: Used when files are involved, or for larger, more complex data.
FastAPI's Form Dependency
FastAPI makes handling form data easy using the Form dependency from fastapi.
It works similarly to Query or Path parameters, but it tells FastAPI to expect the data in the request body as form fields.
You import it like this: from fastapi import FastAPI, Form.
Basic Form Endpoint Example
Let's create an endpoint that accepts a username and password as form data. Notice how username and password are explicitly marked with Form(...).
This tells FastAPI to parse them from the form body, not as JSON or query parameters.
from fastapi import FastAPI, Form
import uvicorn
app = FastAPI()
@app.post("/login/")
async def login(username: str = Form(...), password: str = Form(...)):
return {"username": username, "message": "Login successful!"}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)Interacting with Form Data
You can test this endpoint using tools like curl or by creating a simple HTML form. The -d flag in curl sends form data.
Make sure your FastAPI application from the previous scene is running!
curl -X POST "http://127.0.0.1:8000/login/" \
-H "Content-Type: application/x-www-form-urlencoded" \
-d "username=coddy&password=secret"File Uploads Explained
Uploading files (like images, documents, or videos) is a common web task. This type of data is sent using multipart/form-data encoding.
FastAPI provides special tools to handle these uploads efficiently, allowing you to access file contents and metadata.
FastAPI's UploadFile
For file uploads, FastAPI uses the UploadFile class (from fastapi) along with the File dependency.
When you declare a parameter with File(...) and type-hint it as UploadFile, FastAPI handles the file stream.
filename: The name of the uploaded file.content_type: The file's MIME type (e.g.,image/jpeg).file: A SpooledTemporaryFile object, allowing you to read its contents.
from fastapi import FastAPI, File, UploadFile
import uvicorn
app = FastAPI()
@app.post("/uploadfile/")
async def create_upload_file(file: UploadFile = File(...)):
return {"filename": file.filename, "content_type": file.content_type}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)Saving One Uploaded File
After receiving an UploadFile, you can read its content and save it to a local disk or cloud storage. Here's how to save it locally.
Remember to handle potential errors during file operations.
from fastapi import FastAPI, File, UploadFile
import uvicorn
import shutil
import os
app = FastAPI()
# Ensure the 'files' directory exists
os.makedirs("files", exist_ok=True)
@app.post("/uploadandsave/")
async def upload_and_save_file(file: UploadFile = File(...)):
file_location = f"files/{file.filename}"
with open(file_location, "wb+") as file_object:
shutil.copyfileobj(file.file, file_object)
return {"message": f"File '{file.filename}' saved at '{file_location}'"}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)Uploading Many Files
What if you need to upload several files at once? FastAPI supports this by allowing you to define a parameter as a list of UploadFile.
Each file in the list will be an UploadFile object, which you can then process individually.
from fastapi import FastAPI, File, UploadFile
from typing import List
import uvicorn
app = FastAPI()
@app.post("/uploadmultiple/")
async def create_upload_files(files: List[UploadFile] = File(...)):
uploaded_filenames = [file.filename for file in files]
return {"filenames": uploaded_filenames, "message": "Files received!"}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)Saving Multiple Uploads
Similar to single files, you can iterate through the list of UploadFile objects and save each one. This is useful for photo galleries or document uploads.
Always ensure proper error handling and secure file storage practices in a real application.
from fastapi import FastAPI, File, UploadFile
from typing import List
import uvicorn
import shutil
import os
app = FastAPI()
# Ensure the 'files' directory exists
os.makedirs("files", exist_ok=True)
@app.post("/uploadandsavemultiple/")
async def upload_and_save_multiple_files(files: List[UploadFile] = File(...)):
saved_files = []
for file in files:
file_location = f"files/{file.filename}"
with open(file_location, "wb+") as file_object:
shutil.copyfileobj(file.file, file_object)
saved_files.append(file.filename)
return {"message": f"Successfully uploaded: {', '.join(saved_files)}"}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)Form & File Check
You've learned about handling form data and file uploads. Let's test your understanding!
Lesson Summary
Great job! In this lesson, you mastered how to handle traditional form data and robust file uploads in FastAPI.
- We used
Form(...)for simple key-value form fields. - We explored
UploadFileandFile(...)for single and multiple file uploads. - You learned to save uploaded files to your server.
These techniques are crucial for building interactive web applications. Keep practicing!
Domande Frequenti
La lezione «Dati dei form e upload di file» è gratuita?
Sì — il testo completo di «Dati dei form e upload di file» è gratuito qui sul web. Per esercitarvi in modo interattivo (un editor di codice integrato e un tutor IA 24/7) e sbloccare il resto del corso FastAPI Backend Development Bootcamp, passa a CoddyKit PRO. Il corso FastAPI Backend Development Bootcamp include 4 lezioni in totale.
Cosa imparerò in «Dati dei form e upload di file»?
Gestisca i dati dei form HTML tradizionali e implementi l'upload di file usando le funzionalità integrate di FastAPI. Eserciti FastAPI Backend Development Bootcamp con codice pratico che esegui direttamente nel browser, e un tutor IA 24/7 risponde alle tue domande mentre lavori sulla lezione.
Ho bisogno di esperienza per iniziare FastAPI Backend Development Bootcamp?
Non è richiesta alcuna esperienza precedente. FastAPI Backend Development Bootcamp su CoddyKit è strutturato per principianti e studenti avanzati, quindi puoi iniziare da qui o dall'inizio e procedere al tuo ritmo. Questa è la lezione 3 di 4.
Quanto tempo richiede la lezione «Dati dei form e upload di file»?
La maggior parte delle lezioni CoddyKit richiede circa 5–10 minuti. Ogni lezione è breve e interattiva, quindi fai progressi costanti e riprendi esattamente da dove hai lasciato su web e app.
Posso scrivere ed eseguire codice in questa lezione FastAPI Backend Development Bootcamp?
Sì. Ogni lezione FastAPI Backend Development Bootcamp include un editor di codice integrato, quindi scrivi ed esegui codice reale direttamente nel tuo browser e ricevi feedback istantaneo dall'IA — nessuna configurazione locale necessaria.
Tutte le lezioni di questo corso
- Modelli Pydantic per il request body
- Modelli di risposta e codici di stato
- Dati dei form e upload di file
- Header, cookie e risposte personalizzate