Changes between Initial Version and Version 1 of NullMediaItem

Timestamp:

09/25/25 16:01:18 (4 months ago)

Author:

bazzuser

Comment:

--

NullMediaItem

@@ +1 @@
+**Purpose of NullMediaItem**
+
+The NullMediaItem class represents the absence of media (image, audio, or video) in a way that avoids special-case handling elsewhere in the code.
+
+It follows the Null Object Pattern
+, which provides a default behavior for "no object" cases, eliminating the need for repetitive if media is not None or if media: checks in templates or logic.
+
+**Why use it?**
+
+Without NullMediaItem:
+
+
+{{{#!python
+if question.media:
+    for m in question.media:
+        if m.type == "image":
+            ...
+}}}
+
+
+
+With NullMediaItem:
+
+
+{{{#!python
+for m in question.media:
+    html += m.to_html()
+}}}
+
+
+
+→ no conditional logic needed – every MediaItem, even the null variant, understands how to behave.
+
+**Behavior of NullMediaItem**
+|| Method ||    Behavior ||
+||type() ||     Returns "none" ||
+|| to_dict() || Returns empty {} or None ||
+|| to_html() || Returns "" (empty string) ||
+
+**When is it used?**
+
+You can attach one or more NullMediaItem()s to a Question instead of using None, [], or omitting the field entirely.
+
+For example:
+
+
+{{{|!python
+question = TextQuestion(
+    qid="q1",
+    text="What is your name?",
+    media=[NullMediaItem()]
+)
+}}}
+
+This way, the rendering pipeline stays uniform, regardless of whether media is present or not.
+
+**Benefits**
+
+- Simplifies templates and rendering logic
+
+- Eliminates null checks in UI code
+
+- Makes polymorphism clean and consistent
+
+- Encourages Tell, Don't Ask design (don’t ask “do you have media?”, just tell media to render itself)