An IETF RFC draft The Hypertext Transfer Protocol (HTTP) Status Code 308 (Permanent Redirect) defines HTTP status 308 as Permanent Redirect. It should, of course, be noted that this is a draft document and contains in its document header the text "Expires: September 27, 2012", which I presume would mean it should be considered invalid now, but I’m not familiar with IETF’s processes and so don’t feel confident about this.
The Wikipedia article List of HTTP status codes uses this definition of 308, also:
308 Permanent Redirect (approved as experimental RFC)[12]
The request, and all future requests should be repeated using another URI. 307 and 308 (as proposed) parallel the behaviours of 302 and 301, but do not allow the HTTP method to change. So, for example, submitting a form to a permanently redirected resource may continue smoothly.
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[12]: "The Hypertext Transfer Protocol (HTTP) Status Code 308 (Permanent Redirect)". IETF. 2012. Retrieved March 27, 2012.
Eric Law, of Microsoft at the time, comments on this HTTP/308 code in Pushing the Web Forward with HTTP/308. That caused me to discover that Firefox supports 308 under this meaning.
However, when I was looking in the python-requests library, I found that there is another usage of 308:
308: ('resume_incomplete', 'resume'),
This seems to come from a Google Gears resumable HTTP requests proposal, defining 308 Resume Incomplete. There seems to be some usage of that. Of course, neither of these proposals acknowledges the existence of the other.
So what’s going on? Is 308 Permanent Redirect alive? What’s happening with the status code 308? What should I do?
The Internet Draft has not expired (as it was approved before it expired). See https://datatracker.ietf.org/doc/draft-reschke-http-status-308/ and http://www.rfc-editor.org/queue2.html#draft-reschke-http-status-308 for the current publication status.