Dify + FastAPIで“ユーザー任せ”のナレッジチャットを作る方法（OneDrive編）

from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse
import requests
import configparser
import os

app = FastAPI()

# 認証情報読み込み
config = configparser.ConfigParser()
config.read("config.cfg")

client_id = config["azure"]["clientId"]
client_secret = config["azure"]["clientSecret"]
tenant_id = config["azure"]["tenantId"]

# アクセストークン取得関数
def get_token():
    url = f"https://login.microsoftonline.com/{tenant_id}/oauth2/v2.0/token"
    payload = {
        "client_id": client_id,
        "client_secret": client_secret,
        "scope": "https://graph.microsoft.com/.default",
        "grant_type": "client_credentials"
    }

    response = requests.post(url, data=payload)
    if response.status_code != 200:
        raise Exception(f"Token Error: {response.text}")
    return response.json()["access_token"]

# OneDriveからExcelダウンロード
def download_excel(user_email: str, filename: str = "test.xlsx", save_as: str = "downloaded_test.xlsx"):
    token = get_token()
    headers = {
        "Authorization": f"Bearer {token}"
    }
    # アプリケーション権限なので「ユーザー指定」が必要
    file_url = f"https://graph.microsoft.com/v1.0/users/{user_email}/drive/root:/{filename}:/content"

    response = requests.get(file_url, headers=headers)
    if response.status_code != 200:
        raise Exception(f"Download Error: {response.text}")

    with open(save_as, "wb") as f:
        f.write(response.content)

    return save_as

# FastAPIルート
@app.get("/download_excel")
def api_download_excel(file_name: str = "test.xlsx"):
    try:
        saved_file = download_excel("taro@example.com", filename=file_name)
        return FileResponse(saved_file, media_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', filename=file_name)
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))