def set_link(url, label, credit)
Utility::check_types({ url=>String, label=>String, credit=>Integer }) if $DEBUG
@status = -1
return false unless @url
turl = @url + "/_set_link"
reqheads = [ "Content-Type: application/x-www-form-urlencoded" ]
reqheads.push("Authorization: Basic " + Utility::base_encode(@auth)) if @auth
reqbody = "url=" + CGI::escape(url) + "&label=" + label
reqbody += "&credit=" + credit.to_s if credit >= 0
rv = Utility::shuttle_url(turl, @pxhost, @pxport, @timeout, reqheads, reqbody, nil, nil)
@status = rv
rv == 200
end