Is there an easy way to add/remove/modify query parameters of a URL in Tritium?

Question

I saw a very manual way of doing this in another post: How do I add a query parameter to a URL?

This doesn't seem very intuitive, but someone there mentioned an easier way to accomplish this using the upcoming "URL scope". Is this feature out yet, and how would I use it?

Answer 1

If you're using the stdlib mixer, you should be able to use the URL scope which provides helper functions for adding, viewing, editing, and removing URL params. Here's a quick example:

$original_url = "http://cuteoverload.com/2013/08/01/buttless-monkey-jams?hi=there"
$new_url = url($original_url) {
  log(param("hi"))
  param("hello", "world")
  remove_param("hi")
}
log($new_url)

Tritium Tester example here: http://tester.tritium.io/9fcda48fa81b6e0b8700ccdda9f85612a5d7442f

Almost forgot, link to docs: http://tritium.io/current (You'll want to click on the URL category).

Answer 2

AFAIK, there's no built-in way of doing so. I'll post here how I did to append a query param, making sure that it does not get duplicated if already on the url:

Inside your functions/main.ts file, you can declare:

# Adds a query parameter to the URL string in scope.
# The parameter is added as the last parameter in
# the query string.
#
# Sample use:
# $("//a[@id='my_link]") {
#   attribute("href") {
#     value() {
#       appendQueryParameter('MVWomen', '1')
#     }
#   }
# }
#
# That will add MVwomen=1 to the end of the query string,
# but before any hash arguments.
# It also takes care of deciding if a ? or a #
# should be used.
@func Text.appendQueryParameter(Text %param_name, Text %param_value) {
    # this beautiful regex is divided in three parts:
    #   1. Get anything until a ? or # is found (or we reach the end)
    #   2. Get anything until a # is found (or we reach the end - can be empty)
    #   3. Get the remainder (can be empty)
    replace(/^([^#\?]*)(\?[^#]*)?(#.*)?$/) {
        var('query_symbol', '?')
        match(%2, /^\?/) {
            $query_symbol = '&'
        }

        # first, it checks if the %param_name with this %param_value already exists
        # if so, we don't do anything
        match_not(%2, concat(%param_name, '=', %param_value)) {

            # We concatenate the URL until ? or # (%1),
            # then the query string (%2), which can be empty or not,
            # then the query symbol (either ? or &),
            # then the name of the parameter we are appending,
            # then an equals sign,
            # then the value of the parameter we are appending
            # and finally the hash fragment, which can be empty or not
            set(concat(%1, %2, $query_symbol, %param_name, '=', %param_value, %3))
        }       
    }
}

The other features you want (remove, modify) can be achieved similarly (by creating a function inside functions/main.ts and leveraging some regex magic).

Hope it helps.