file1.php

All error objects have resource and field properties so that your client can tell what the problem is. There’s also an error code to let you know what is wrong with the field. These are the possible validation error codes:

missing
This means a resource does not exist.
missing_field
This means a required field on a resource has not been set.
invalid
This means the formatting of a field is invalid. The documentation for that resource should be able to give you more specific information.
already_exists
This means another resource has the same value as this field. This can happen in resources that must have some unique key (such as Label names).
If resources have custom validation errors, they will be documented with the resource.

HTTP Verbs