SID Killer Lua

-- Store Location: HTTP header in variable
local location_header = ngx.header.location

-- Only run if Location: header is present
if location_header then
  -- Set the cookie lifetime to 1 day
  local expires = 3600 * 24

  -- Extract sid= value into the sid_cookie variable
  local sid_cookie, err = ngx.re.match(location_header, "^http(s)?:/\/\.+sid=(.+)$", "io")

  -- Only run if extraction was successful
  if sid_cookie then
    -- Construct new cookie named sessionid from sid=
    ngx.header.Set_Cookie = "sessionid=" .. sid_cookie[2] .. "; path=/; domain=.tripelover.com; Expires=" .. ngx.cookie_time(ngx.time() + expires)

    -- Sanitize sid= parameter from redirection URL in the response
    ngx.header.location = ngx.re.sub(location_header, "^(http.*).sid=.*$", "$1", "o")
  end
end