基于Zappa、API Gateway与AWS Cognito的第三方API回调URL问询

Hey there! Let's walk through how to handle this third-party API callback requirement while keeping your existing Zappa/AWS Cognito/API Gateway setup intact. Here's a step-by-step breakdown tailored to your current stack:

First, you'll need to add a new route specifically for the third-party API to send data to. Since this request comes directly from the third-party service (not your authenticated client), it won't carry your Cognito ID Token—so we'll handle permissions separately.

Example Flask Route (adjust for Django if needed): #

from flask import request, jsonify
import hmac
import hashlib

# Add this to your existing routes file
@app.route("/api/third-party-callback", methods=["POST"])
def third_party_callback():
    # First, verify the request actually comes from the third party
    # Replace with the signature method your third-party API uses
    received_signature = request.headers.get("X-Third-Party-Signature")
    secret_key = "YOUR_SHARED_SECRET_WITH_THIRD_PARTY"
    computed_signature = hmac.new(
        secret_key.encode(), request.data, hashlib.sha256
    ).hexdigest()

    if received_signature != computed_signature:
        return jsonify({"error": "Invalid request signature"}), 403

    # Extract user identifier to link the third-party data to your Cognito user
    # This depends on how you passed the user context to the third party (see step 3)
    user_sub = request.json.get("state")  # Or from query params if using GET
    third_party_user_data = request.json.get("user_data")

    # Save the data to your database, linked to the Cognito user
    save_third_party_user_data(user_sub, third_party_user_data)

    return jsonify({"status": "success"}), 200

Update Zappa & API Gateway Permissions: #

• When you deploy with zappa update, Zappa will sync this new route to API Gateway.
• Head to the API Gateway console, find your new /api/third-party-callback resource, and set its Authorization Type to NONE (since the third party won't have your Cognito tokens). But don't skip the signature verification above—this is critical for security.

Your callback URL will be your API Gateway's public domain plus the new endpoint. It should look something like:
https://your-api-id.execute-api.your-region.amazonaws.com/prod/api/third-party-callback

• Confirm this URL is publicly accessible (if the third-party API is cloud-based). If your API is private, add a resource policy in API Gateway to allow the third party's IP ranges to access this specific endpoint.

To connect the third-party's callback data to the right user in your system:

• When your client initiates the third-party authorization flow, pass your Cognito user's sub (unique user ID) as a state parameter to the third party. Most APIs support this parameter and will echo it back in the callback.
• Example client-side initiation:

// Get current user's Cognito sub from your auth state
const currentUserSub = Auth.currentUserInfo().then(user => user.attributes.sub);
// Build third-party auth URL with state parameter
const thirdPartyAuthUrl = `https://third-party.com/auth?client_id=YOUR_CLIENT_ID&redirect_uri=YOUR_CALLBACK_URL&state=${currentUserSub}`;
// Redirect user to third-party auth page
window.location.href = thirdPartyAuthUrl;

• Validate the state parameter: For added CSRF protection, generate a random string alongside the user's sub, store it in your client's session, and verify it matches the value returned in the callback.
• Restrict IP access: If the third party provides a fixed set of IPs for callbacks, add them to an API Gateway resource policy to block unauthorized requests.

• Use Postman or curl to simulate a third-party callback request to your new endpoint, ensuring signature verification and data saving work as expected.
• Do a full end-to-end test: initiate the auth flow from your client, complete third-party authorization, and confirm the data lands in your database linked to the correct user.

内容的提问来源于stack exchange，提问作者speechMachine