Function keyGenerator

source/rate-limit.ts:233–261

(request: Request, response: Response)

			response.statusCode < 400,
		skip: (_request: Request, _response: Response): boolean => false,
		async keyGenerator(request: Request, response: Response): Promise<string> {
			// By default, use the IP address (for IPv4) or subnet (for IPv6) to rate limit users.

			// Run the validation checks on the IP and headers to make sure everything
			// is working as intended.
			validations.ip(request.ip)
			validations.trustProxy(request)
			validations.xForwardedForHeader(request)
			validations.forwardedHeader(request)

			// Note: eslint thinks the ! is unnecessary but dts-bundle-generator disagrees
			// biome-ignore lint/style/noNonNullAssertion: validations.ip is called above
			const ip: string = request.ip!
			let subnet: number | false = 56

			if (isIPv6(ip)) {
				// Apply subnet to ignore the bits that he end-user controls and rate-limit on only the bits their ISP controls
				subnet =
					typeof config.ipv6Subnet === 'function'
						? await config.ipv6Subnet(request, response)
						: config.ipv6Subnet

				// If it was a function, check the output now (otherwise it got checked earlier)
				if (typeof config.ipv6Subnet === 'function')
					validations.ipv6Subnet(subnet)
			}

			return ipKeyGenerator(ip, subnet)
		},
		ipv6Subnet: 56,
		async handler(
			request: Request,