transferSubscriptionOwnership

The transferSubscriptionOwnership Firebase Cloud Function enables the current owner of a subscription to transfer its ownership to another user. This involves updating the Stripe customer’s email and changing the owner_id in Firestore.

Function Signature

export const transferSubscriptionOwnership = https.onCall(async (data: TransferSubscriptionData, context) => { ... });

Parameters

The function expects the following data in the data object:

TransferSubscriptionData Interface:

interface TransferSubscriptionData {
    subscriptionId: string;
    newOwnerId: string;
}

Context

The function requires an authenticated user context (context.auth). The authenticated user must be the current owner of the specified subscription.

Behavior

1. Authentication Check: Verifies that the user calling the function is authenticated. If not, it throws an unauthenticated error.
2. Input Validation: Ensures subscriptionId and newOwnerId are provided.
3. Subscription Retrieval: Fetches the subscription document from Firestore using the provided subscriptionId.
   • If the subscription does not exist, it throws a not-found error.
4. Current Owner Verification: Checks if the authenticated user is the current owner_id of the subscription. If not, it throws a permission-denied error.
5. Stripe Customer ID Check: Ensures a stripe_customer_id exists for the subscription. If not, it throws a failed-precondition error.
6. New Owner Email Retrieval: Fetches the new owner’s Firebase Auth user record to get their email address.
   • If the new owner does not have an email, it throws a failed-precondition error.
7. Stripe Customer Email Update: Updates the email of the associated Stripe customer to the new owner’s email.
8. Firestore Ownership Update: Updates the subscription document in Firestore, setting the owner_id to newOwnerId.
9. Success: Returns an object containing success: true, subscriptionId, newOwnerId, and stripeCustomerId.

Error Handling

The function throws HttpsError with specific codes for different failure scenarios:

• unauthenticated: If the user is not authenticated.
• not-found: If the subscription is not found.
• permission-denied: If the user is not the current subscription owner.
• failed-precondition: If no Stripe customer ID is found for the subscription, or if the new owner does not have an email address.
• internal: For any Stripe API errors or other unexpected errors during execution.

Example Usage (Client-side)

import { getFunctions, httpsCallable } from 'firebase/functions';
import { getApp } from 'firebase/app';

const functions = getFunctions(getApp());
const transferSubscriptionOwnershipCallable = httpsCallable(functions, 'transferSubscriptionOwnership');

async function callTransferSubscriptionOwnership(subscriptionId: string, newOwnerId: string) {
    try {
        const result = await transferSubscriptionOwnershipCallable({ subscriptionId, newOwnerId });
        console.log('Subscription ownership transferred successfully:', result.data);
        // Expected result.data: { success: true, subscriptionId: "sub_...", newOwnerId: "...", stripeCustomerId: "..." }
    } catch (error) {
        console.error('Error transferring subscription ownership:', error.code, error.message);
    }
}

// Example call
// callTransferSubscriptionOwnership('sub_your_stripe_subscription_id', 'new_owner_uid');