Toggle Features

Enable or disable features which may or may not be experimental/web version only.

// ==UserScript==
// @name        Toggle Features
// @description Enable or disable features which may or may not be experimental/web version only.
// @author      bertigert
// @version     1.0.3
// @icon        https://www.google.com/s2/favicons?sz=64&domain=deezer.com
// @namespace   Violentmonkey Scripts
// @match       https://www.deezer.com/*
// @grant       none
// @run-at      document-start
// ==/UserScript==


(function() {
    "use strict";
    // ======= Settings START =======


    const LOG_ALL_FEATURES_DEBUG = true; // useful to see all features (gets logged in the (dev tools) console, use https://github.com/bertigert/DeezMod/blob/main/plugins/enable_dev_mode.js to view)


    const DEEZER_CUSTOM_FEATURES = {
        // gapless_playback: true,
        deeztools: true, // simple way to toggle most of the custom features
    }

    // true = enable, false = disable, null = leave as is (only some features differentiate between false and null)
    const SPECIAL_FEATURES = {
        spoof_family: false, // Spoof your account to be the head of a family plan if you are a child account of a family account, opening up more features for you. (e.g. linking to last.fm)
        download_on_web: null, // Enable downloading on the web version of Deezer
    }

    // ======= Settings END =======



    function log(...args) {
        console.log("[Toggle Features]", ...args);
    }
    function error(...args) {
        console.error("[Toggle Features]", ...args);
    }
    function debug(...args) {
        console.debug("[Toggle Features]", ...args);
    }

    function get_user_id(resp_json) {
        return resp_json.results.USER.USER_ID;
    }

    function patch(resp_json) {
        // Special features
        if (SPECIAL_FEATURES.spoof_family) {
            resp_json.results.USER.MULTI_ACCOUNT = {"ENABLED": true,"ACTIVE": true,"CHILD_COUNT": 0,"MAX_CHILDREN": 0,"PARENT": null,"IS_KID": false,"IS_SUB_ACCOUNT": false}
        }

        if (SPECIAL_FEATURES.download_on_web) {
            localStorage.setItem("deezTools_features_offline_"+get_user_id(resp_json), "true");
        } else if (SPECIAL_FEATURES.download_on_web === false) {
            localStorage.removeItem("deezTools_features_offline_"+get_user_id(resp_json));
        }


        // Deezer custom features
        const features = resp_json.results.__DZR_GATEKEEPS__;

        if (LOG_ALL_FEATURES_DEBUG) {
            log('All Features:', features, "Special Features:", SPECIAL_FEATURES);
        }

        for (let feature of Object.entries(DEEZER_CUSTOM_FEATURES)) {
            features[feature[0]] = feature[1];
            log(feature[1] ? 'Enabled' : 'Disabled', feature[0]);
        }
    }

    class Hooks {
        static HOOK_INDEXES = Object.freeze({
            FETCH: 0,
            ALL: 1
        });

        // we use this approach to unhook to avoid unhooking hooks created after our hooks
        static is_hooked = [true]; // start enabled since we only hook once

        static toggle_hooks(enabled, ...args) {
            for (const arg of args) {
                switch (arg) {
                    case Hooks.HOOK_INDEXES.ALL:
                        Hooks.is_hooked.fill(enabled);
                        return;
                    case Hooks.HOOK_INDEXES.FETCH:
                        Hooks.is_hooked[arg] = enabled;
                        break;
                }
            }
        }
    }

    const original_fetch = window.fetch;

    log("Hooking fetch");

    async function hooked_fetch(...args) {
        if (!Hooks.is_hooked[Hooks.HOOK_INDEXES.FETCH]) return original_fetch.apply(this, args);

        try {
            const url = new URL(args[0]);

            if (url.pathname !== "/ajax/gw-light.php" ||
                url.searchParams.get("method") !== "deezer.getUserData" ||
                url.searchParams.get("api_token") !== "" ||
                !url.searchParams.has("cid") ||
                typeof args[1].body !== "string"
            ) {
                return original_fetch.apply(window, args);
            }

            debug('Catched user data fetch call');

            const response = await original_fetch.apply(window, args);
            const resp_json = await response.json();

            if (resp_json.results) {
                patch(resp_json);
            }

            // since this request is only made once, we can unhook now
            debug("Unhooking fetch");
            Hooks.toggle_hooks(false, Hooks.HOOK_INDEXES.ALL);

            return new Response(JSON.stringify(resp_json), {
                status: response.status,
                statusText: response.statusText,
                headers: response.headers,
            });
        } catch (e) {
            error("Error in fetch hook:", e);
            return original_fetch.apply(window, args);
        }
    }

    // only change the function which gets called, not the attributes of the original fetch function
    Object.setPrototypeOf(hooked_fetch, original_fetch);
    Object.getOwnPropertyNames(original_fetch).forEach(prop => {
        try {
            hooked_fetch[prop] = original_fetch[prop];
        } catch (e) {}
    });
    window.fetch = hooked_fetch;
    window.fetch._modified_by_toggle_features = true;
})();