Make sure to properly initialize the HAR collector

Author: janodvarko

lib/trigger-toolbox-overlay.js

@@ -80,8 +80,7 @@ const TriggerToolboxOverlay = Class(
       return;
     }
 
-    let autoExportToFile = Services.prefs.getBoolPref(
-      "devtools.netmonitor.har.enableAutoExportToFile");
+    let harOverlay = getHarOverlay(this.toolbox);
 
     // Call make remote to make sure the target.client exists.
     let target = this.toolbox.target;
@@ -92,11 +91,30 @@ const TriggerToolboxOverlay = Class(
       // But, if users want to use HAR content API to trigger HAR export
       // when needed, HAR automation needs to be activated. Let's do it now
       // if 'extensions.netmonitor.har.enableAutomation' preference is true.
-      if (prefs.enableAutomation && !autoExportToFile) {
-        let harOverlay = getHarOverlay(this.toolbox);
+      if (prefs.enableAutomation && !harOverlay.automation) {
+        Trace.sysout("TriggerToolboxOverlay.onReady; Init automation");
+
+        // Initialize automation.
         harOverlay.initAutomation();
       }
 
+      // This is a bit hacky, but the HarAutomation starts monitoring
+      // after target.makeRemote() promise is resolved.
+      // It's resolved after the parent target.makeRemote() (we are just within)
+      // finishes.
+      // So, let's register another promise handler and reset the collector
+      // after the HarAutomation.startMonitoring() is actually executed.
+      target.makeRemote().then(() => {
+        // Make sure the collector exists. The collector is automatically
+        // created when the page load begins, but the toolbox can be opened
+        // in the middle of page session (after page load event).
+        // And HAR API consumer might want to export any time.
+        let automation = harOverlay.automation;
+        if (automation && !automation.collector) {
+          automation.resetCollector();
+        }
+      });
+
       this.attach().then(front => {
         Trace.sysout("TriggerToolboxOverlay.onReady; HAR driver ready!");
       });