Almost all responses, including error situations like 404, will include the X-Archive-Error- headers, but there might be situations where you will not receive them (a.e. if using a proxy, and there’s a problem with the proxy itself), so although your code should take advantage of the information in these headers, it should not require that they are present.
|X-Archive-Error-Code||This is a numeric error code meant to facilitate machine handling of specific errors. An overview of current error codes is available in Error codes.|
|X-Archive-Error-Message||A human readable description of the error.|
|X-Archive-Info-Code||A numeric info code used to report back success for specific operations. So far the only value is -1000, which means "upload succeeded", and is only returned when uploading a document.|
|X-Archive-Info-Message||A human readable description of the successful result.|
|X-Archive-Index-Name||If a given metadata field is part of an error, this header will contain the field name.|
|X-Archive-Index-Value||If a given metadata field is part of an error, this header will contain the field value. This header may be omitted if there is no value associated with the field.|