Sending JSON payload from Smartthings SmartApp to Google Firebase Cloud Message

SmartthingsHttpPostJsonToFirebase.groovy

/* 
Example of Smartthings SmartApp to send downstream cloud message with Firebase
Event subscription is needed to trigger the event handler
*/

def installed() {
	initialize()
}

def updated() {
	unsubscribe()
	initialize()
}

/* Subscribe the event to the handler */
def initialize() {
	subscribe(switches,"switch",sendEventToFirebase)
}

/* Send event data to Google Firebase from http POST */
def sendEventToFirebase(evt){

	def serverKey = "Firebase Server Key"
	def clientToken = "Client Device Token"

	def params = [
		uri: "https://fcm.googleapis.com/fcm/send",
		headers: [
			Authorization: "key=" + serverKey
		],
		body: [
			to: clientToken,
			data: [
				deviceId: evt.deviceId,
				eventName: evt.name,
				value: evt.stringValue]
			]
	]

	try {
		httpPostJson(params) { resp ->
			resp.headers.each {
				//log.debug "${it.name} : ${it.value}"
			}
			log.debug "DEBUG (POST FIREBASE): response contentType: ${resp.    contentType}"
		}
	} catch (e) {
		log.debug "something went wrong: $e"
	}

}