The cloak_url tag, as the name suggests, can be used to cloak links so that it does not become apparent from just looking at the links as to where they actually lead to.
Please see Core Concepts - Cloaked Links for a detailed discussion of this tag.
The link (URL) to cloak.
This parameter can be used to set a time (in seconds) after which the link produced wll no longer be valid.
If an access level is set by this parameter, only authenticated users with the right level of privileges will be able to access the link.
This parameter works in tandem with the access_level parameter above. With this parameter set to '1', if a link that has an access level set on it is accessed by someone who is not privileged enough, a login box is shown to hime thus promting him to login for accessing the link.
By default, this parameter is '0' and unauthorized users are simply served a blank page.
If this parameter is set to '1', the user is redirected to the link provided (by issuing a HTTP 302 redirect).
By default, this tag evaluates the type of the file being linked to and sends back proper Content-Type to the browser. This causes the browser to display certain files (e.g. image files like gif, png etc.) directly while displaying a messagebox prompting the user to download certain types of files (e.g. executables, zip files etc.).
If this parameter is set to '1', Couch will cause the browser to always display the download box regardless of the type of file being served.
It is a self closing tag and does not set any variables of its own.