cancelSubscription

The cancelSubscription Firebase Cloud Function enables the owner of a subscription to cancel it. This function interacts with Stripe to cancel the subscription and updates its status in Firestore.

Function Signature

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

Parameters

The function expects the following data in the data object:

CancelSubscriptionData Interface:

interface CancelSubscriptionData {
    subscriptionId: string;
    confirmationId: string;
}

Context

The function requires an authenticated user context (context.auth).

Behavior

1. Authentication Check: Verifies that the user calling the function is authenticated. If not, it throws an unauthenticated error.
2. Subscription Retrieval: Fetches the subscription document from Firestore using the provided subscriptionId.
   • If the subscription does not exist, it throws a not-found error.
3. Owner Verification: Checks if the authenticated user is the owner (owner_id) of the subscription. If not, it throws a permission-denied error.
4. Confirmation ID Validation: Ensures that confirmationId matches subscriptionId. If not, it throws an invalid-argument error.
5. Stripe Cancellation: Calls the Stripe API to cancel the subscription.
6. Firestore Update: Updates the subscription document in Firestore, setting its status to ‘canceled’ and subscription_end to the current timestamp.
7. Success: Returns { success: true, subscriptionId } upon successful cancellation.

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 subscription owner.
• invalid-argument: If confirmationId does not match subscriptionId.
• internal: For any 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 cancelSubscriptionCallable = httpsCallable(functions, 'cancelSubscription');

async function callCancelSubscription(subscriptionId: string) {
    try {
        // For security, confirmationId should typically be derived or confirmed by the user
        const confirmationId = subscriptionId; // In a real app, this might be a user input
        const result = await cancelSubscriptionCallable({ subscriptionId, confirmationId });
        console.log('Subscription canceled successfully:', result.data);
        // Expected result.data: { success: true, subscriptionId: "sub_..." }
    } catch (error) {
        console.error('Error canceling subscription:', error.code, error.message);
    }
}

// Example call
// callCancelSubscription('sub_your_stripe_subscription_id');