Update app.py

app.py

@@ -24,6 +24,23 @@ def _zip_dir(folder: str, zip_path: str) -> None:
                 rel = os.path.relpath(full, folder)
                 z.write(full, rel)
 
+def _safe_extract_zip(zip_path: str, dst_dir: str) -> None:
+    """Safely extract FASTA files from ZIP (prevents zip-slip)."""
+    with zipfile.ZipFile(zip_path, "r") as z:
+        for member in z.infolist():
+            if member.is_dir():
+                continue
+
+            target = os.path.normpath(os.path.join(dst_dir, member.filename))
+            if not target.startswith(os.path.abspath(dst_dir) + os.sep):
+                continue
+
+            if not member.filename.lower().endswith((".fa", ".fasta", ".fas", ".fna")):
+                continue
+
+            os.makedirs(os.path.dirname(target), exist_ok=True)
+            with z.open(member) as src, open(target, "wb") as out:
+                shutil.copyfileobj(src, out)
 
 def run_prediction(unknown_files, kmer_zip, seqtype, mode, identity, coverage, fdr):
     if not unknown_files: