通过Microsoft Graph API从OneDrive提取数据需准备哪些信息？

Hey Chris, let's walk through everything you need to get set up for pulling data from OneDrive via Microsoft Graph API—since there's a bit more to it than just an API key. Here's a detailed breakdown of the requirements and configurations:

Before you can call Graph API, you need to register an application in Azure Active Directory (Azure AD). This is how Microsoft identifies and authenticates your app.

• Choose the right account type:
  • If this is for your organization only, pick "Accounts in this organizational directory only".
  • If you need to access personal Microsoft accounts (like outlook.com) or multiple orgs, go with "Accounts in any organizational directory and personal Microsoft accounts".
• Set a redirect URI:
  • For desktop/console apps, use https://login.microsoftonline.com/common/oauth2/nativeclient (this is a standard URI for native apps).
  • For web apps, enter your app's callback URL (where users are sent after authorizing).

That "API key" you mentioned is actually a client secret (or certificate) tied to your Azure AD app. But you'll need to pair it with the right authentication flow based on your use case:

• Client Credentials Flow (best for background services, no user interaction):
  • Uses your client ID + client secret (API key) + tenant ID to get an access token. This flow works with application permissions (see below) to access data across your tenant (e.g., all users' OneDrives, if you have admin consent).
• Authorization Code Flow (for user-facing apps):
  • Requires users to log in and grant permission. Uses client ID + client secret + redirect URI + a user-generated authorization code to get tokens. This accesses the logged-in user's OneDrive via delegated permissions.
• Device Code Flow (for headless/UI-less devices like servers or IoT):
  • Generates a code that users enter on microsoft.com/devicelogin to authorize your app, then you fetch the token.

Permissions control what your app can access in OneDrive/Graph API. There are two main types:

• Delegated Permissions (user-specific, requires user consent):
  • Files.Read: Read files/folders in the logged-in user's OneDrive.
  • Files.Read.All: Read all files the user has access to (including shared files/folders from others or SharePoint).
  • Sites.Read.All: Access SharePoint site document libraries (if your data lives there instead of personal OneDrive).
• Application Permissions (tenant-wide, requires admin consent):
  • Files.Read.All: Read all files across all users' OneDrives in your tenant.
  • Sites.Read.All: Read all SharePoint site content in your tenant.

  Important: Any permission with .All (especially application permissions) needs admin approval. You can request this in the Azure AD app portal under "API permissions" → "Grant admin consent for [your tenant]".

Once your app is registered and permissions are set, you need an access token to call Graph API:

• For Client Credentials Flow, send a POST request to https://login.microsoftonline.com/{your-tenant-id}/oauth2/v2.0/token with these form parameters:

  grant_type=client_credentials
  client_id={your-client-id}
  client_secret={your-api-key}
  scope=https://graph.microsoft.com/.default
  

• For other flows, you'll follow a multi-step process to get an authorization code first, then exchange it for a token.
• Once you have the token, include it in every Graph API request header: Authorization: Bearer {your-access-token}

Here are some common endpoints to pull OneDrive data:

• Get the logged-in user's OneDrive root folder: GET https://graph.microsoft.com/v1.0/me/drive/root
• List files in a specific folder (replace {folder-path} with your target folder): GET https://graph.microsoft.com/v1.0/me/drive/root:/{folder-path}:/children
• Get the content of a specific file (replace {file-id}): GET https://graph.microsoft.com/v1.0/me/drive/items/{file-id}/content
• If using application permissions to access another user's OneDrive, replace me with their user ID: GET https://graph.microsoft.com/v1.0/users/{user-id}/drive/root

• Rate Limits: Graph API enforces rate limits to prevent abuse. If you get a 429 Too Many Requests error, implement a retry logic with exponential backoff.
• Token Expiry: Access tokens expire after ~60 minutes. For flows with refresh tokens (like Authorization Code), use the refresh token to get a new access token without re-authenticating the user. For Client Credentials Flow, just request a new token when the old one expires.
• Consent: For delegated permissions, the first time a user uses your app, they'll see a consent screen asking to allow your app access to their OneDrive.

内容的提问来源于stack exchange，提问作者Chris