feat(messaging): migrate topic subscriptions to FCM v1 API - #3211
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lahirumaramba wants to merge 4 commits into
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feat(messaging): migrate topic subscriptions to FCM v1 API#3211lahirumaramba wants to merge 4 commits into
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This pull request migrates the topic subscription and unsubscription management in the Firebase Messaging service to the FCM v1 API, while preserving the old behavior under deprecated legacy methods. It introduces concurrent request handling with a limit for both HTTP/1.1 and HTTP/2 transports. The review feedback highlights a potential runtime TypeError when parsing server error responses if the error field is null, and identifies an opportunity to reduce code duplication in the task mapping logic for HTTP/1.1 and HTTP/2 requests.
Migrate `subscribeToTopic` and `unsubscribeFromTopic` methods in `admin.messaging.Messaging` from legacy Instance ID (IID) endpoints (`iid.googleapis.com/iid/v1`) to the modernized single-token Firebase Cloud Messaging (FCM) v1 Topics Subscription REST API (`fcm.googleapis.com/v1`).
- Update `subscribeToTopic` (`CreateTopicSubscription`) and `unsubscribeFromTopic` (`DeleteTopicSubscription`) to use HTTP/2 transport by default (or HTTP/1.1 via `enableLegacyHttpTransport()`).
- Implement client-side concurrency pooling (`runWithConcurrencyLimit`) bounded to 100 concurrent requests per batch to avoid HTTP/2 stream exhaustion.
- Preserve idempotency by treating `ALREADY_EXISTS` (HTTP 409) as success for subscription requests, and `NOT_FOUND` (HTTP 404) as `REGISTRATION_TOKEN_NOT_REGISTERED` for unsubscription requests.
- Add legacy backup/escape-hatch methods `subscribeToTopicLegacy` and `unsubscribeFromTopicLegacy` annotated with `@deprecated Use {@link Messaging.subscribeToTopic} instead.` and `@deprecated Use {@link Messaging.unsubscribeFromTopic} instead.`.
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August 25, 2026 18:35
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Migrate
subscribeToTopicandunsubscribeFromTopicmethods inadmin.messaging.Messagingfrom legacy Instance ID (IID) endpoints (iid.googleapis.com/iid/v1) to the modernized single-token Firebase Cloud Messaging (FCM) v1 Topics Subscription REST API (fcm.googleapis.com/v1).subscribeToTopic(CreateTopicSubscription) andunsubscribeFromTopic(DeleteTopicSubscription) to use HTTP/2 transport by default (or HTTP/1.1 viaenableLegacyHttpTransport()).runWithConcurrencyLimit) bounded to 100 concurrent requests per batch to avoid HTTP/2 stream exhaustion.ALREADY_EXISTS(HTTP 409) as success for subscription requests, andNOT_FOUND(HTTP 404) asREGISTRATION_TOKEN_NOT_REGISTEREDfor unsubscription requests.subscribeToTopicLegacyandunsubscribeFromTopicLegacyannotated with@deprecated Use {@link Messaging.subscribeToTopic} instead.and@deprecated Use {@link Messaging.unsubscribeFromTopic} instead..