$baseUri ?raw=1&method=lookup&apiKey= [uri escape uri $apiKey] \
          &package= [uri escape uri $package] &version= [uri escape uri \
          $version]]
    } else {
      package require http 2.0

      return [appendArgs \
          $baseUri ? [::http::formatQuery raw 1 method lookup \
          apiKey $apiKey package $package version $version]]
    }
  }

  #
  # NOTE: This procedure returns the version of the package that should be
  #       used to lookup the associated [package ifneeded] script -OR- an
  #       empty string if no such version exists.  The package argument is

        #
        set token [eval [list ::http::geturl $uri] $args]

        #
        # NOTE: Check the HTTP response code, in order to follow any HTTP
        #       redirect responses.
        #
        switch -exact -- [::http::ncode $token] {
          301 -
          302 -
          303 -
          307 {
            #
            # NOTE: Unless the caller forbids it, display progress messages
            #       when an HTTP redirect is returned.