Replace AbortSignal.timeout

because one of the devices I want this to run on doesn't support that.
Also check heap usage on request for prometheus, rather than every
second.

data/index.js

@@ -19,8 +19,19 @@ update_time=Date.now()
 }
 
 function update(){
-fetch('data.json',{method:'get',signal:AbortSignal.timeout(3000)})
+var options={method:'GET'}
+var timeout
+if(typeof(AbortController)=='function'){
+const abort=new AbortController();
+options.signal=abort.signal
+timeout=setTimeout(()=>abort.abort(),3000);
+}
+
+fetch('data.json',options)
 .then((res)=>{
+if(timeout!=undefined){
+clearTimeout(timeout)
+}
 return res.json()
 }).then((out)=>{
 temp_elemen.innerText=out.temperature
@@ -29,6 +40,9 @@ time_element.innerText=time_element.dateTime=out.time
 json_time=parseTimeString(out.time)
 update_time=Date.now()
 }).catch((err)=>{
+if(timeout!=undefined){
+clearTimeout(timeout)
+}
 console.error('Error: ',err)
 })
 }

src/html/index.js

@@ -29,8 +29,19 @@ function init() {
  * This function fetches new measurements from the ESP and updates the page.
  */
 function update() {
-	fetch('data.json', { method: 'get', signal: AbortSignal.timeout(3000) })
+	var options = { method: 'GET' }
+	var timeout
+	if (typeof (AbortController) == 'function') {
+		const abort = new AbortController();
+		options.signal = abort.signal
+		timeout = setTimeout(() => abort.abort(), 3000);
+	}
+
+	fetch('data.json', options)
 		.then((res) => {
+			if (timeout != undefined) {
+				clearTimeout(timeout)
+			}
 			return res.json()
 		}).then((out) => {
 			temp_elemen.innerText = out.temperature
@@ -39,6 +50,9 @@ function update() {
 			json_time = parseTimeString(out.time)
 			update_time = Date.now()
 		}).catch((err) => {
+			if (timeout != undefined) {
+				clearTimeout(timeout)
+			}
 			console.error('Error: ', err)
 		})
 }

src/prometheus.cpp

@@ -15,9 +15,6 @@
 #include <sstream>
 #include "fallback_log.h"
 
-#ifdef ESP32// From what I could find this seems to be impossible on a ESP8266.
-uint32_t prom::used_heap = 0;
-#endif
 #if ENABLE_WEB_SERVER == 1 && (ENABLE_PROMETHEUS_PUSH == 1 || ENABLE_PROMETHEUS_SCRAPE_SUPPORT == 1)
 std::map<String, std::map<std::pair<WebRequestMethod, uint16_t>, uint64_t>> prom::http_requests_total;
 #endif
@@ -36,11 +33,6 @@ void prom::setup() {
 }
 
 void prom::loop() {
-#ifdef ESP32// From what I could find this seems to be impossible on a ESP8266.
-	// TODO move to getMetrics
-	used_heap = ESP.getHeapSize() - ESP.getFreeHeap();
-#endif
-
 #if ENABLE_PROMETHEUS_PUSH == 1
 	pushMetrics();
 #endif
@@ -114,6 +106,7 @@ String prom::getMetrics(const bool openmetrics) {
 
 	// From what I could find this seems to be impossible on a ESP8266.
 #ifdef ESP32
+	const uint64_t used_heap = ESP.getHeapSize() - ESP.getFreeHeap();
 	len += writeMetric(buffer + len, "process", "heap", "bytes",
 			"The amount of heap used on the ESP in bytes.", "gauge",
 			(double) used_heap, openmetrics);

src/prometheus.h

@@ -33,9 +33,6 @@
  * This header, and the source file with the same name, contain everything for the prometheus integration.
  */
 namespace prom {
-#ifdef ESP32// From what I could find this seems to be impossible on a ESP8266.
-extern uint32_t used_heap;
-#endif
 #if ENABLE_WEB_SERVER == 1 && (ENABLE_PROMETHEUS_PUSH == 1 || ENABLE_PROMETHEUS_SCRAPE_SUPPORT == 1)
 extern std::map<String, std::map<std::pair<WebRequestMethod, uint16_t>, uint64_t>> http_requests_total;
 #endif