OFans.party IPFS Gateway Switcher

IPFS gateway switcher for ofans.party.

Versión del día 27/04/2021. Echa un vistazo a la versión más reciente.

// ==UserScript==
// @name        OFans.party IPFS Gateway Switcher
// @namespace   Violentmonkey Scripts
// @description IPFS gateway switcher for ofans.party.
// @match       https://ofans.party/*
// @grant       GM_xmlhttpRequest
// @grant       GM_getValue
// @grant       GM_setValue
// @grant       GM_deleteValue
// @run-at      document-start
// @version     0.4
// @author      sudorain
// @noframes
// ==/UserScript==

// A (somewhat working) polyfill for beforescriptexecute event
// https://github.com/jspenguin2017/Snippets/blob/master/onbeforescriptexecute.html

(() => {
  "use strict";

  const Event = class {
    constructor(script, target) {
      this.script = script;
      this.target = target;

      this._cancel = false;
      this._replace = null;
      this._stop = false;
    }

    preventDefault() {
      this._cancel = true;
    }
    stopPropagation() {
      this._stop = true;
    }
    replacePayload(payload) {
      this._replace = payload;
    }
  };

  let callbacks = [];
  window.addBeforeScriptExecuteListener = (f) => {
    if (typeof f !== "function") {
      throw new Error("Event handler must be a function.");
    }
    callbacks.push(f);
  };
  window.removeBeforeScriptExecuteListener = (f) => {
    let i = callbacks.length;
    while (i--) {
      if (callbacks[i] === f) {
        callbacks.splice(i, 1);
      }
    }
  };

  const dispatch = (script, target) => {
    if (script.tagName !== "SCRIPT") {
      return;
    }

    const e = new Event(script, target);

    if (typeof window.onbeforescriptexecute === "function") {
      try {
        window.onbeforescriptexecute(e);
      } catch (err) {
        console.error(err);
      }
    }

    for (const func of callbacks) {
      if (e._stop) {
        break;
      }
      try {
        func(e);
      } catch (err) {
        console.error(err);
      }
    }

    if (e._cancel) {
      script.textContent = "";
      script.remove();
    } else if (typeof e._replace === "string") {
      script.textContent = e._replace;
    }
  };
  const observer = new MutationObserver((mutations) => {
    for (const m of mutations) {
      for (const n of m.addedNodes) {
        dispatch(n, m.target);
      }
    }
  });
  observer.observe(document, {
    childList: true,
    subtree: true,
  });
})();


(async () => {
  "use strict";

  var loaded, regex_main_js, gateways_json, public_gateways, current_gateway, gallery_mode;

  loaded = false;
  regex_main_js = new RegExp(/main\.[a-z0-9]+\.chunk\.js/);

  // A site displaying public IPFS gateways and their online/offline status.
  // https://ipfs.github.io/public-gateway-checker/
  gateways_json = "https://ipfs.github.io/public-gateway-checker/gateways.json";
  public_gateways = await GM_getValue("public_gateways");
  current_gateway = await GM_getValue("current_gateway");
  gallery_mode = await GM_getValue("gallery_mode");

  await GM_xmlhttpRequest({
    method: "GET",
    url: gateways_json,
    onload: function (response) {
      public_gateways = response.responseText.replace(/:hash/g, "");
      GM_setValue("public_gateways", public_gateways)
    }
  });

  window.onbeforescriptexecute = (e) => {
    const script = e.script.outerHTML;
    if (regex_main_js.test(script) && !loaded && current_gateway) {
      const source = e.script.attributes.src.value;
      e.preventDefault();
      e.stopPropagation();
      GM_xmlhttpRequest({
        method: "GET",
        url: source,
        onload: function (response) {
          loaded = !loaded
          let text = response.responseText.replace(/ipfsHost:"(.*?)"/g, `ipfsHost:"${current_gateway}"`);
          let newScript = createElement('script', text, { type: "text/javascript", id: "main" });
          document.head.append(newScript);
        }
      });
    }
  }

  document.addEventListener('DOMContentLoaded', function () {

    let css = `
      .custom-scrollbar::-webkit-scrollbar {
        width: 5px;
      }
      .custom-scrollbar::-webkit-scrollbar-track {
        background: #dee2e6; 
      }
      .custom-scrollbar::-webkit-scrollbar-thumb {
        background: #888; 
      }
      .custom-scrollbar::-webkit-scrollbar-thumb:hover {
        background: #555; 
      }
    `;

    let style = createElement('style', css);
    document.head.append(style);

    const gateways = JSON.parse(public_gateways)

    let wrapper = createElement('div', false, { class: "position-absolute fixed-bottom float-left text-monospace mb-3 ml-3", style: "width: fit-content;" });

    let dropdown_group = createElement('div', false, { id: "switch", class: "btn-group dropup" });
    let button = createElement('button', "Gateways ", { class: "btn btn-dark dropdown-toggle", "data-toggle": "dropdown", "aria-haspopup": "true", "aria-expanded": "false" });
    let badge = createElement('span', gateways.length, { class: "badge badge-light" });
    button.append(badge)
    dropdown_group.append(button)

    let dropdown_menu = createElement('div', false, { class: "dropdown-menu overflow-auto custom-scrollbar shadow-lg px-0 pt-0 pb-2 mb-3", style: "max-height: 388px" });
    for (const [index, url] of gateways.entries()) {
      let current = current_gateway == url;
      let fancy_url = url.match(/(^https?:\/\/)(.*)/);
      let url_protocol = createElement('small', fancy_url[1], { class: `${current ? ' ' : ' text-black-50'}` });
      let menu_item = createElement('button', fancy_url[2], { "data-value": url, class: `dropdown-item border-bottom button-switch ${current ? ' active' : ' text-dark'}`, type: "button" });
      menu_item.prepend(url_protocol)
      if (current) {
        dropdown_menu.prepend(menu_item)
      } else {
        dropdown_menu.append(menu_item)
      }
    }
    let dafault_gateway = createElement('button', 'Default', { "data-value": '', class: `dropdown-item border-bottom border-top button-switch ${!current_gateway ? ' active' : ''}`, type: "button" });
    dropdown_menu.prepend(dafault_gateway)
    let menu_header = createElement('h6', "Gateway Switcher", { class: "bg-light text-dark shadow-sm sticky-top dropdown-header border-bottom py-3 mb-2" });
    let menu_checker = createElement('a', "Public Gateway Checker ", { class: "float-right text-success", href: "https://ipfs.github.io/public-gateway-checker/", target: "_blank" });
    menu_header.append(menu_checker)
    dropdown_menu.prepend(menu_header)
    dropdown_group.append(dropdown_menu)
    wrapper.append(dropdown_group)
    document.body.append(wrapper)

  });

  document.addEventListener("click", switchGateway);

  function switchGateway(e) {
    const class_list = e.target.classList;
    const data_set = e.target.dataset;
    if (class_list.contains('button-switch')) {
      const value = data_set.value;
      if (value) {
        GM_setValue("current_gateway", value)
      } else {
        GM_deleteValue("current_gateway")
      }
      location.reload();
    }
  }

  function createElement(el, text, attrs) {
    let element = document.createElement(el);
    if (text) element.textContent = text;
    if (attrs) Object.keys(attrs).forEach(key => element.setAttribute(key, attrs[key]));
    return element;
  }

})();