New authority censor rules are not applied to existing responses

[lizconlan]

If you add a censor rule to an authority after a response has been published, the intended redaction only applies to the correspondence header until the message cache (e.g. cached_main_body_text_unfolded) is cleared.

The censor rule intention was to replace the last name of the sender.

(May be looking in the wrong place but I can't see how an admin can fix this)

[lizconlan]

Related to #1156

[garethrees]

Needs expire requests before redirecting https://github.com/mysociety/alaveteli/blob/develop/app/controllers/admin_censor_rule_controller.rb#L102-L106

Note that PublicBody doesn't have #expire_requests, but it does have purge_in_cache so worth checking the differences there and seeing whether we can unify these methods a bit.

[lizconlan]

purge_in_cache is for the Varnish cache, user.expire_requests calls .expire on each request which clears the database caches, cache files and the download zip directory (then calls purge_in_cache). I think PublicBody probably needs its own version

[garethrees]

Reopening as the existing requests with body censor rules need to get recached.

CensorRule.where('public_body_id IS NOT NULL').each do |rule|
  rule.public_body.info_requests.find_in_batches(batch_size: 100) do |group|
    group.each do |info_request|
      info_request.expire
      puts "Cleared InfoRequest: #{ info_request.id }"
    end
  end
end

[garethrees]

Requests with public body censor rules have been expired.