[fix] Automatic upgrade upgrade to HTTPS on failure

libview/src/view-def.ts

@@ -299,6 +299,20 @@ export function getResourceContent(
         let xmlHttp = new XMLHttpRequest();
         xmlHttp.onreadystatechange = function() {
           if (xmlHttp.readyState == 4) {
+            if (xmlHttp.status == 0 && uri.startsWith("http://")) {
+              // try https
+              getResourceContent(cache, {
+                location: ViewResourceLocation.remote,
+                uri: "https:" + uri.substring("http:".length)
+              } as ViewResourceRemote)
+                .then((result: string) => {
+                  resolve(result);
+                })
+                .catch((reason: any) => {
+                  reject("Failed to fetch: " + reason);
+                });
+              return;
+            }
             if (xmlHttp.status < 200 || xmlHttp.status >= 300) {
               reject("HTTP error: " + xmlHttp.status);
               return;