Serve Chemiscope viewer from local file

app.py

@@ -301,38 +301,26 @@ def _infer_space_origin():
 
 
 def _build_chemiscope_embed(dataset_payload: dict, dataset_path: str) -> str:
-    """Create HTML content for Chemiscope visualization, preferring hosted datasets."""
-    space_origin = _infer_space_origin()
-    if space_origin and dataset_path:
-        relative_path = Path(dataset_path).as_posix()
-        dataset_url = f"{space_origin}/file={urllib.parse.quote(relative_path)}"
-        iframe_src = f"https://chemiscope.org/?load={urllib.parse.quote(dataset_url, safe='')}"
-        return (
-            "<div style='width:100%;'>"
-            "<iframe "
-            "title='Chemiscope explorer' "
-            "style='width:100%;height:620px;border:none;border-radius:8px;' "
-            f"src='{iframe_src}'></iframe>"
-            "<p style='font-size:0.9em;margin-top:0.5rem;'>"
-            "Open in a new tab if the viewer looks blank: "
-            f"<a href='{iframe_src}' target='_blank' rel='noopener'>chemiscope.org</a>"
-            "</p>"
-            "</div>"
-        )
-
+    """Create HTML content for Chemiscope visualization served locally from the Space."""
     template_html = _load_chemiscope_template()
     dataset_json = json.dumps(dataset_payload, ensure_ascii=False, separators=(",", ":"))
     combined = template_html + dataset_json
-    encoded = base64.b64encode(combined.encode("utf-8")).decode("ascii")
+
+    dataset_file = Path(dataset_path)
+    viewer_name = dataset_file.name.replace(".json.gz", "_viewer.html")
+    viewer_path = dataset_file.parent / viewer_name
+    viewer_path.write_text(combined, encoding="utf-8")
+
+    iframe_src = f"/file={urllib.parse.quote(viewer_path.as_posix())}"
     return (
         "<div style='width:100%;'>"
         "<iframe "
-        "title='Chemiscope explorer (offline fallback)' "
+        "title='Chemiscope explorer' "
         "style='width:100%;height:620px;border:none;border-radius:8px;' "
-        f"src='data:text/html;base64,{encoded}'></iframe>"
+        f"src='{iframe_src}'></iframe>"
         "<p style='font-size:0.9em;margin-top:0.5rem;'>"
-        "Use the map view to explore descriptors interactively or download the dataset for "
-        "https://chemiscope.org/. "
+        "Open in a new tab if the viewer looks blank: "
+        f"<a href='{iframe_src}' target='_blank' rel='noopener'>Chemiscope standalone</a>"
         "</p>"
         "</div>"
     )