如何从Google Smart Home Action获取授权令牌？同步意图未返回令牌咨询

Got it, let's clear this up because Google's Smart Home auth flow works a bit differently from Alexa, which is probably where the confusion is coming from. Here's what you need to do:

Key Difference from Alexa #

First, unlike Alexa which sends the authorization token directly in each request payload, Google handles token management behind the scenes. You won't find the token in the SYNC intent JSON body—instead, it's passed in the HTTP request headers.

Step 1: Verify Your OAuth 2.0 Setup #

Make sure you've correctly configured the OAuth 2.0 flow in the Google Actions Console and your cloud service:

• Your service must support the Authorization Code Flow (Google doesn't support implicit flow for smart home actions).
• In the Actions Console, double-check your Authorization URL and Token URL are pointing to the correct endpoints on your server.
• Your Token endpoint must return both an access_token (short-lived) and refresh_token (long-lived) when Google exchanges the authorization code. Google needs the refresh token to automatically fetch new access tokens as needed.

Step 2: Check the HTTP Request Headers #

When Google sends the SYNC (or any other) intent to your cloud service, it includes the valid access token in the Authorization header, formatted like this:

Authorization: Bearer <your-access-token-here>

Don't just look at the JSON payload—you need to inspect the request headers. For example:

• In Node.js/Express: Use req.headers.authorization
• In Python/Flask: Use request.headers.get('Authorization')

Step 3: Confirm Account Linking is Fully Completed #

Sometimes a "successful" link might have hidden issues. Try re-triggering account linking from the Google Home app or Actions Console test tab, then check your server logs to ensure:

• The authorization code was exchanged for a valid access/refresh token.
• Google received the refresh token correctly (it won't send access tokens if it doesn't have a valid refresh token to refresh them).

Step 4: Debugging Tips #

• Log every incoming request's headers and body to your server—this will help you confirm if the Authorization header is being sent.
• Ensure your OAuth client settings (in your identity provider) have refresh tokens enabled—some services disable this by default, which breaks Google's token refresh flow.

Remember, once the initial account linking is done, Google handles all token refresh logic on its end. Your only job is to validate the access token in each request header before processing the intent.

内容的提问来源于stack exchange，提问作者Ankit Kumar Saini