[OAI-implementers] error reporting

[Stuart Chalk]

> How about for when the database is down, or other low-level
> problems?
>   I for one would like to use something like:
>
> <error code="ServerDown">Service unavailable.  Retry in one
> hour</error>
>
>  with a 503 code, but obviously that's not in the protocol.

Actually, this is in the protocol

>From the v2.0 specficiations document

3.1.2.2 Status-Code
OAI-PMH errors are distinguished from HTTP Status-Codes. Since OAI-PMH
uses HTTP as a transport layer, servers implementing OAI-PMH must conform
to HTTP status code definitions and report relevant HTTP transport layer
status via those Status-Codes. OAI-PMH repositories may employ HTTP
Status-Codes in addition to "200 OK".For instance, the following
Status-Codes may be useful for load balancing in OAI repositories:

*	302 - Allows the repository to temporarily redirect an OAI-PMH
request to another repository. The URI of the temporary repository should
be given by the Location field in the HTTP response.
*	503 - Service unavailable, a Retry-After period is specified.
Harvesters should wait this period before attempting another OAI-PMH
request.

Stuart