Ignore unavailable elements (#119)

CHANGELOG.md

@@ -30,6 +30,9 @@ ambiguous situations.
 
 ## Fixed
 - Crawling of exercises with instructions
+- Don't download unavailable elements.  
+  Elements that are unavailable (for example, because their availability is
+  time restricted) will not download the HTML for the info page anymore.
 
 ## 3.8.2 - 2025-04-29
 

PFERD/crawl/ilias/ilias_web_crawler.py

@@ -329,6 +329,15 @@ instance's greatest bottleneck.
         # directory escape attacks.
         element_path = PurePath(parent_path, element.name)
 
+        # This is symptomatic of no access to the element, for example, because
+        # of time availability restrictions.
+        if "cmdClass=ilInfoScreenGUI" in element.url and "cmd=showSummary" in element.url:
+            log.explain(
+                "Skipping element as url points to info screen, "
+                "this should only happen with not-yet-released elements"
+            )
+            return None
+
         if element.type in _VIDEO_ELEMENTS:
             if not self._videos:
                 log.status(