proper cache busting

utils/asset_utils.py

@@ -0,0 +1,49 @@
+import os
+import hashlib
+from functools import lru_cache
+from flask import current_app
+
+@lru_cache(maxsize=128)
+def get_file_hash(filepath):
+    """
+    Get the MD5 hash of a file's contents.
+    Uses LRU cache to avoid re-reading files that haven't changed.
+    
+    Args:
+        filepath: The path to the file
+        
+    Returns:
+        str: The MD5 hash of the file contents
+    """
+    try:
+        with open(filepath, 'rb') as f:
+            return hashlib.md5(f.read()).hexdigest()
+    except (IOError, OSError):
+        return None
+
+def get_asset_version(filename):
+    """
+    Get the version hash for a static asset.
+    
+    Args:
+        filename: The filename of the static asset
+        
+    Returns:
+        str: The version hash or None if file not found
+    """
+    if not filename:
+        return None
+        
+    # Get the absolute path to the static file
+    static_dir = os.path.join(current_app.root_path, 'static')
+    filepath = os.path.join(static_dir, filename)
+    
+    # Get the file hash
+    file_hash = get_file_hash(filepath)
+    
+    # If file not found or error reading, return None
+    if not file_hash:
+        return None
+        
+    # Return first 8 characters of hash as version
+    return file_hash[:8]