background.js

// Filter out utm_* query parameters
function clean_utm(requestDetails) {
    var url = new URL(requestDetails.url)
    //console.log("cleanURL utm_*", url.href);

    if (url.search.length > 0) {
        var params = url.searchParams;
        var new_params = new URLSearchParams(params);
        var needs_redirect = false;
        for (let p of params.keys()) {
            if (p.startsWith("utm_")) {
                needs_redirect = true;
                new_params.delete(p);
            }
        }
        if (needs_redirect) {
            var new_url = new URL(url);
            new_url.search = new_params.toString();
            /*console.info("Removing utm_* params from url: ",
                requestDetails.url, "  and redirection to: ",
                new_url.href);*/
            return {
                redirectUrl: new_url.href
            }
        }
    }


    return {
    }
}

browser.webRequest.onBeforeRequest.addListener(
    clean_utm,
    {urls: ["<all_urls>"],
     types:["main_frame"]},
    ["blocking"]
);


function clean_amazon(requestDetails) {
    var url = requestDetails.url;
    let slash_d_index = url.indexOf("/d");
    let slash_ref_index = url.indexOf("/ref=", slash_d_index + 2);
    if (slash_ref_index > 0 && url.length > slash_ref_index + 1) {
        var new_url = url.substring(0, slash_ref_index + 1);
        if (new_url != url) {   // try to avoid infinite redirect loops that might arise
            //console.info("Redirecting from: ", url, " to:", new_url);
            return {redirectUrl: new_url};
        }
    } else {
        url = new URL(url);
        if (url.search.length > 0) {
            url.search = "";
            //console.info("Clean url to:", url.href);
            return {redirectUrl: url.href};
        }
    }
}

browser.webRequest.onBeforeRequest.addListener(
    clean_amazon,
    {urls: [
        "*://*.amazon.com/d/*",
        "*://*.amazon.ca/d/*",
        "*://*.amazon.co.jp/d/*",
        "*://*.amazon.co.uk/d/*",
        "*://*.amazon.cn/d/*",
        "*://*.amazon.de/d/*",
        "*://*.amazon.fr/d/*",
        "*://*.amazon.in/d/*",
        "*://*.amazon.it/d/*",
        "*://*.amazon.com.mx/d/*",
        "*://*.amazon.com.au/d/*",
        "*://*.amazon.com.br/d/*",

        "*://*.amazon.com/dp/*",
        "*://*.amazon.ca/dp/*",
        "*://*.amazon.co.jp/dp/*",
        "*://*.amazon.co.uk/dp/*",
        "*://*.amazon.cn/dp/*",
        "*://*.amazon.de/dp/*",
        "*://*.amazon.fr/dp/*",
        "*://*.amazon.in/dp/*",
        "*://*.amazon.it/dp/*",
        "*://*.amazon.com.mx/dp/*",
        "*://*.amazon.com.au/dp/*",
        "*://*.amazon.com.br/dp/*",

        "*://*.amazon.com/gp/aw/d/*",
        "*://*.amazon.ca/gp/aw/d/*",
        "*://*.amazon.co.jp/gp/aw/d/*",
        "*://*.amazon.co.uk/gp/aw/d/*",
        "*://*.amazon.cn/gp/aw/d/*",
        "*://*.amazon.de/gp/aw/d/*",
        "*://*.amazon.fr/gp/aw/d/*",
        "*://*.amazon.in/gp/aw/d/*",
        "*://*.amazon.it/gp/aw/d/*",
        "*://*.amazon.com.mx/gp/aw/d/*",
        "*://*.amazon.com.au/gp/aw/d/*",
        "*://*.amazon.com.br/gp/aw/d/*",


        "*://*.amazon.com/*/dp/*",
        "*://*.amazon.ca/*/dp/*",
        "*://*.amazon.co.jp/*/dp/*",
        "*://*.amazon.co.uk/*/dp/*",
        "*://*.amazon.cn/*/dp/*",
        "*://*.amazon.de/*/dp/*",
        "*://*.amazon.fr/*/dp/*",
        "*://*.amazon.in/*/dp/*",
        "*://*.amazon.it/*/dp/*",
        "*://*.amazon.com.mx/*/dp/*",
        "*://*.amazon.com.au/*/dp/*",
        "*://*.amazon.com.br/*/dp/*",

        "*://*.amazon.com/gp/product/*",
        "*://*.amazon.ca/gp/product/*",
        "*://*.amazon.co.jp/gp/product/*",
        "*://*.amazon.co.uk/gp/product/*",
        "*://*.amazon.cn/gp/product/*",
        "*://*.amazon.de/gp/product/*",
        "*://*.amazon.fr/gp/product/*",
        "*://*.amazon.in/gp/product/*",
        "*://*.amazon.it/gp/product/*",
        "*://*.amazon.com.mx/gp/product/*",
        "*://*.amazon.com.au/gp/product/*",
        "*://*.amazon.com.br/gp/product/*",
    ], types: ["main_frame"]},
    ["blocking"]
);


function remove_searchparams(requestDetails) {
    var url = new URL(requestDetails.url)
    if (url.search.length > 0) {
        url.search = "";
        //console.info("Clean url to:", url.href);
        return {redirectUrl: url.href};
    }
}
browser.webRequest.onBeforeRequest.addListener(
    remove_searchparams,
    {
        urls: [
            "*://*.aliexpress.com/item/*.html*",
            "*://*.aliexpress.com/store/product/*.html*",
        ], types: ["main_frame"]
    }, ["blocking"]
);

function build_redirect_to_query_param(query_param_name){
  const redirect_to_get_param = function(requestDetails){
    const search_params = new URLSearchParams(new URL(requestDetails.url).search);
    const real_url_from_param = search_params.get(query_param_name);
    if (real_url_from_param){
      // console.log('Redirecting to ' + real_url_from_param);
      return {redirectUrl: real_url_from_param};
    }
  }
  return redirect_to_get_param;
}

const urls_to_param_mappers = [
  {
    urls: ["*://l.facebook.com/*"],
    param_name: 'u'
  },
  {
    urls: ["*://out.reddit.com/*"]
  },
  {
    urls: ["*://steamcommunity.com/linkfilter/*"]
  }
];

urls_to_param_mappers.forEach(function(listenerConfig) {
  const param_name = listenerConfig.param_name ? listenerConfig.param_name : 'url';
  // console.log('Mapping ' + listenerConfig.urls + ' to param name ' + param_name);
  browser.webRequest.onBeforeRequest.addListener(
    build_redirect_to_query_param(param_name), {
      urls: listenerConfig.urls,
      types: ["main_frame"]
    }, ["blocking"]
  );
});