fix empty query

app.py

@@ -180,14 +180,6 @@ if __name__ == "__main__":
         css=".underline-on-hover:hover { text-decoration: underline; } .flagging { font-size:12px; color:Silver; }"
     )
 
-    def submit(query, lang, k):
-        if query == "":
-            raise ValueError("Invalid query provided")
-        return {
-            results: scisearch(query, lang, k),
-            flagging_form: gr.update(visible=True),
-        }
-
     with demo:
         with gr.Row():
             gr.Markdown(value=description)
@@ -235,6 +227,14 @@ if __name__ == "__main__":
             flag_btn = gr.Button("Flag Results")
             flag_btn.click(flag, inputs=[query, lang, k, flag_txt], outputs=[flag_txt])
 
+        def submit(query, lang, k):
+            query = query.strip()
+            if query is None or query == "":
+                return "", ""
+            return {
+                results: scisearch(query, lang, k),
+                flagging_form: gr.update(visible=True),
+            }
         query.submit(fn=submit, inputs=[query, lang, k], outputs=[results, flagging_form])
         submit_btn.click(submit, inputs=[query, lang, k], outputs=[results, flagging_form])