This commit takes the existing remove bucket functionality written by
brendanashworth, integrates it to the current UI with a dropdown for
each bucket, and fixes small issues that were present, like the dropdown
not disappearing after the user clicks on 'Delete' for certain buckets.
This feature only deletes a bucket that is empty (that has no objects).
Fixes#4166
This commit fixes a potential security issue, whereby a full-access
token to the server would be available in the GET URL of a download
request. This fixes that issue by introducing short-expiry tokens, which
are only valid for one minute, and are regenerated for every download
request.
This commit specifically introduces the short-lived tokens, adds tests
for the tokens, adds an RPC call for generating a token given a
full-access token, updates the browser to use the new tokens for
requests where the token is passed as a GET parameter, and adds some
tests with the new temporary tokens.
Refs: https://github.com/minio/minio/pull/4673
