Update app.py

app.py

@@ -12,10 +12,21 @@ def download_pdf(url):
         file.write(response.content)
     return file_path
 
+import json
+
 def get_doi(pdf_path):
     pdf2doi.config.set('verbose', False)
     results = pdf2doi.pdf2doi(pdf_path)
-    validation_info = results['validation_info']  # Already a dict
+    validation_info = results.get('validation_info', {})
+    if isinstance(validation_info, str):  
+        try:
+            validation_info = json.loads(validation_info)  # Convert JSON string to dic
+        except json.JSONDecodeError as e:
+            print(f"Error decoding JSON: {e}")
+            return None, None, None
+    if not isinstance(validation_info, dict):
+        print("Validation info is not a dictionary")
+        return None, None, None
     doi = validation_info.get('DOI', None)
     title = validation_info.get('title', None)
     url = validation_info.get('URL', None)