Update app.py

app.py

@@ -20,6 +20,8 @@ def format_output(extracted_content, repo_url):
 def extract_and_display(url):
     hf_token = os.getenv("HF_TOKEN")
     hf_user = os.getenv("SPACE_AUTHOR_NAME")
+    if not hf_token or not hf_user:
+        return "Error: HF_TOKEN or SPACE_AUTHOR_NAME environment variable is not set."
     extracted_content = extract_repo_content(url, hf_token, hf_user)
     formatted_output = format_output(extracted_content, url)
     return formatted_output