Non-idempotent request duplication during $http retry logic

Request Deduplication in AngularJS $http

AngularJS 1.x does not provide a native mechanism for automatic request retries or built-in deduplication for HTTP calls. When implementing custom retry logic via interceptors or wrapper services, there is a risk of duplicating writes for non-idempotent methods such as POST, PUT, or PATCH if a request fails due to a network timeout after the server has already processed the operation.

Because the $http service does not track request identity or provide a framework-level idempotency key, the responsibility for preventing duplicate data entries falls entirely on the application layer.

Design Constraints

• The framework does not distinguish between safe (GET, HEAD) and unsafe methods during manual retry cycles.
• Interceptors operate on the request/response chain without a native state machine to track previous attempts of the same logical operation.

Should a standardized retry helper default to retrying only safe methods, and if so, what is the recommended pattern for opting into unsafe method retries without disrupting existing interceptor chains?