add method to retrieve har

grattoir/__init__.py

@@ -31,6 +31,13 @@ def install_har_export_trigger(driver):
     return driver
 
 
+def har_data(self)
+    return self.execute_async_script(
+    "HAR.triggerExport().then(arguments[0]);"
+)
+
+
+
 class Grattoir(object):
     def __enter__(self):
         self._driver = None
@@ -45,6 +52,7 @@ class Grattoir(object):
         o.binary = binary
         self._driver = firefox.webdriver.WebDriver(options=o)
         self._driver = install_har_export_trigger(self._driver)
+        self._driver = har_data
         return self._driver
 
     def __exit__(self, exc_type, exc_value, exc_tb):