erp5_jio_connector: properly handle errors

bt5/erp5_jio_connector/DocumentTemplateItem/portal_components/document.erp5.JioApiConnector.py

@@ -53,10 +53,18 @@ class JioApiConnector(XMLObject):
     user_credentials = (self.getUserId(), self.getPassword())
     r = requests.post(get_url, json=request_dict, auth=user_credentials)
 
-    if r.status_code not in [200, 201]:
-      return None
+    # Return response when status code is as expected
+    if r.status_code in [200, 201]:
+      return r.json()
 
-    return r.json()
+    # Try to get an error message by parsing JSON
+    result = None
+    try:
+      result = r.json()
+    except:
+      raise Exception("Error when sending to API ({}): API returned invalid JSON".format(r.status_code))
+
+    raise Exception("Error when sending to API ({}): {}".format(r.status_code, result["message"]))
 
   def getFromApi(self, request_dict):
     return self._sendToApi("/get", request_dict)