Telegram Media Downloader

Used to download streaming videos on Telegram

当前为 2023-05-15 提交的版本,查看 最新版本

您需要先安装一个扩展,例如 篡改猴Greasemonkey暴力猴,之后才能安装此脚本。

You will need to install an extension such as Tampermonkey to install this script.

您需要先安装一个扩展,例如 篡改猴暴力猴,之后才能安装此脚本。

您需要先安装一个扩展,例如 篡改猴Userscripts ,之后才能安装此脚本。

您需要先安装一款用户脚本管理器扩展,例如 Tampermonkey,才能安装此脚本。

您需要先安装用户脚本管理器扩展后才能安装此脚本。

(我已经安装了用户脚本管理器,让我安装!)

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展,比如 Stylus,才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

您需要先安装一款用户样式管理器扩展后才能安装此样式。

(我已经安装了用户样式管理器,让我安装!)

// ==UserScript==
// @name         Telegram Media Downloader
// @version      0.3
// @namespace    https://github.com/Neet-Nestor/Telegram-Media-Downloader
// @description  Used to download streaming videos on Telegram
// @author       Nestor Qin
// @license      GNU GPLv3
// @website      https://github.com/Neet-Nestor/Telegram-Media-Downloader
// @match        https://web.telegram.org/*
// @match        https://webk.telegram.org/
// @match        https://webz.telegram.org/
// @icon         https://img.icons8.com/color/452/telegram-app--v5.png
// @grant        none
// ==/UserScript==

(function () {
  const logger = {
    info: (message) => {
      console.log("[Tel Download] " + message);
    },
    error: (message) => {
      console.error("[Tel Download] " + message);
    },
  };

  const contentRangeRegex = /^bytes (\d+)-(\d+)\/(\d+)$/;

  const tel_download_video = (url) => {
    let _blobs = [];
    let _next_offset = 0;
    let _total_size = null;
    let _file_extension = "mp4";

    const fetchNextPart = () => {
      fetch(url, {
        method: "GET",
        headers: {
          Range: `bytes=${_next_offset}-`,
        },
      })
        .then((res) => {
          logger.info("get response ", res);
          if (![200, 206].includes(res.status)) {
            logger.error("Non 200/206 response was received: " + res.status);
            return;
          }

          const mime = res.headers.get("Content-Type").split(";")[0];
          if (!mime.startsWith("video/")) {
            logger.error("Get non video response with MIME type " + mime);
            throw "Get non video response with MIME type " + mime;
          }
          _file_extension = mime.split("/")[1];

          const match = res.headers
            .get("Content-Range")
            .match(contentRangeRegex);

          const startOffset = parseInt(match[1]);
          const endOffset = parseInt(match[2]);
          const totalSize = parseInt(match[3]);

          if (startOffset !== _next_offset) {
            logger.error("Gap detected between responses.");
            logger.info("Last offset: " + _next_offset);
            logger.info("New start offset " + match[1]);
            throw "Gap detected between responses.";
          }
          if (_total_size && totalSize !== _total_size) {
            logger.error("Total size differs");
            throw "Total size differs";
          }

          _next_offset = endOffset + 1;
          _total_size = totalSize;

          logger.info(
            `Get response: ${res.headers.get(
              "Content-Length"
            )} bytes data from ${res.headers.get("Content-Range")}`
          );
          logger.info(
            `Progress: ${((_next_offset * 100) / _total_size).toFixed(0)}%`
          );
          return res.blob();
        })
        .then((resBlob) => {
          _blobs.push(resBlob);
        })
        .then(() => {
          if (_next_offset < _total_size) {
            fetchNextPart();
          } else {
            save();
          }
        })
        .catch((reason) => {
          logger.error(reason);
        });
    };

    const save = () => {
      logger.info("Finish downloading blobs");
      logger.info("Concatenating blobs and downloading...");

      let fileName =
        (Math.random() + 1).toString(36).substring(2, 10) +
        "." +
        _file_extension;

      // Some video src is in format:
      // 'stream/{"dcId":5,"location":{...},"size":...,"mimeType":"video/mp4","fileName":"xxxx.MP4"}'
      try {
        const metadata = JSON.parse(decodeURIComponent(url.split('/')[url.split('/').length - 1]));
        logger.info(metadata)
        if (metadata.fileName) {
          fileName = metadata.fileName;
        }
      } catch (e) {
        // Invalid JSON string, pass extracting filename
      }

      const blob = new Blob(_blobs, { type: "video/mp4" });
      const blobUrl = window.URL.createObjectURL(blob);

      logger.info("Final blob size: " + blob.size + " bytes");

      const a = document.createElement("a");
      document.body.appendChild(a);
      a.href = blobUrl;
      a.download = fileName;
      a.click();
      document.body.removeChild(a);
      window.URL.revokeObjectURL(blobUrl);

      logger.info("Download triggered");
    };

    fetchNextPart();
  };

  const tel_download_image = (imageUrl) => {
    const fileName =
      (Math.random() + 1).toString(36).substring(2, 10) + ".jpeg"; // assume jpeg

    const a = document.createElement("a");
    document.body.appendChild(a);
    a.href = imageUrl;
    a.download = fileName;
    a.click();
    document.body.removeChild(a);

    logger.info("Download triggered");
  };

  logger.info("Initialized");

  // Copied and modified from Heroicons (https://heroicons.com/)
  const downloadIcon = `
  <svg xmlns="http://www.w3.org/2000/svg" style="height:24px;width:24px;" fill="none" viewBox="0 0 24 24" stroke="currentColor" stroke-width="2">
    <path stroke-linecap="round" stroke-linejoin="round" d="M7 16a4 4 0 01-.88-7.903A5 5 0 1115.9 6L16 6a5 5 0 011 9.9M9 19l3 3m0 0l3-3m-3 3V10" />
  </svg>`;

  const createOrReplaceDownloadButton = (container, url, type) => {
    if (!container.querySelector("._tel_download_button_img_container")) {
      const innerContainer = document.createElement("div");
      innerContainer.className = "_tel_download_button_img_container";
      innerContainer.style.position = "absolute";
      innerContainer.style.width = "100%";
      innerContainer.style.height = "100%";
      innerContainer.style.display = "flex";
      innerContainer.style.justifyContent = "center";
      innerContainer.style.alignItems = "end";
      container.appendChild(innerContainer);
    }
    const innerContainer = container.querySelector('._tel_download_button_img_container');
    const currentButton = innerContainer && innerContainer.querySelector('._tel_download_button_img');
    const downloadButton = document.createElement("button");
    downloadButton.className =
      "btn-icon default__button _tel_download_button_img";
    downloadButton.innerHTML = downloadIcon;
    downloadButton.setAttribute('data-href', url);
    downloadButton.style.marginBottom = "16px";
    downloadButton.style.backgroundColor = "black";
    downloadButton.onclick = (e) => {
      e.stopPropagation();
      if (type === 'image') {
        tel_download_image(url);
      } else if (type === 'video') {
        tel_download_video(url);
      }
    };
    if (currentButton === null) {
      // Create the button
      container.appendChild(innerContainer);
      innerContainer.appendChild(downloadButton);
    } else if (currentButton.getAttribute('data-href') !== url) {
      // Replace the button
      innerContainer.innerHTML = '';
      innerContainer.appendChild(downloadButton);
    }
  };

  setInterval(() => {
    // All media opened are located in .media-viewer-movers > .media-viewer-aspecter
    const mediaContainer = document.querySelector(
      ".media-viewer-movers .media-viewer-aspecter"
    );
    if (!mediaContainer) return;

    // 1. Video player detected - Video and it has finished initial loading
    // container > .ckin__player > video[src]
    if (mediaContainer.querySelector(".ckin__player")) {
      // remove download img button if there's any
      document
        .querySelectorAll("._tel_download_button_img_container")
        .forEach((e) => e.remove());

      // add download button to videos
      const controls = mediaContainer.querySelector(
        ".default__controls.ckin__controls"
      );
      const videoUrl = mediaContainer.querySelector("video").src;

      if (controls && !controls.querySelector("._tel_download_button_video")) {
        const brControls = controls.querySelector(
          ".bottom-controls .right-controls"
        );
        const downloadButton = document.createElement("button");
        downloadButton.className = "btn-icon default__button _tel_download_button_video";
        downloadButton.innerHTML = downloadIcon;
        downloadButton.onclick = () => {
          tel_download_video(videoUrl);
        };
        brControls.prepend(downloadButton);
      }
      // 2. Video HTML element detected, could be either GIF or unloaded video
      // container > video[src]
    } else if (mediaContainer.querySelector("video") && mediaContainer.querySelector("video")) {
      const videoUrl = mediaContainer.querySelector("video").src;
      createOrReplaceDownloadButton(mediaContainer, videoUrl, 'video');
      // 3. Image detected
      // container > img.thumbnail
    } else if (!mediaContainer.querySelector("._tel_download_button_img") && mediaContainer.querySelector("img.thumbnail")) {
      // add download button to images
      const imageUrl = mediaContainer.querySelector("img.thumbnail").src;
      createOrReplaceDownloadButton(mediaContainer, imageUrl, 'image');
    }
  }, 500);
})();