Sha1 has known to be deprecated for a while so allow the formpost
middleware to use SHA256 and SHA512. Follow the tempurl model and
accept signatures of the form:
<hex-encoded signature>
or
sha1:<base64-encoded signature>
sha256:<base64-encoded signature>
sha512:<base64-encoded signature>
where the base64-encoding can be either standard or URL-safe, and the
trailing '=' chars may be stripped off.
As part of this, pull the signature-parsing out to a new function, and
add detection for hex-encoded sha512 signatures to tempurl.
Change-Id: Iaba3725551bd47d75067a634a7571485b9afa2de
Related-Change: Ia9dd1a91cc3c9c946f5f029cdefc9e66bcf01046
Co-Authored-By: Tim Burke <tim.burke@gmail.com>
Closes-Bug: #1794601
ef31baf3fc