Make a dead thread look like it's still alive.

reanimate.js

/* Thread Reanimater
 * =================
 *
 * Make a dead thread look like it's still alive.
 *
 *
 * How to use
 * ==========
 *
 * If you want to use a board other than /mlp/ or an archive other than Desu,
 * see "Configuration" below.
 *
 * 1. Open any live thread (i.e. https://boards.4channel.org/mlp/thread/...)
 * 2. On that page, open the JavaScript console of your browser (look it up if
 *    you don't know how), paste this entire file, and press enter.
 * 3. Find the thread you want on Desuarchive and copy the ID.
 * 4. Run the following command in the console, substituting THREAD_ID for your
 *    thread ID:
 *
 *        reanimateThread(THREAD_ID)
 *
 *    If you want to show deleted posts, pass true as the second argument:
 *
 *        reanimateThread(THREAD_ID, true)
 *
 *    You can do this as many times as you want, but if you refresh the page,
 *    you'll have to start over from step 2.
 *
 *
 * Configuration
 * =============
 *
 * This script is designed for /mlp/ and Desu, but it may work with other
 * boards and archives.
 * Change "BOARD" to the board you want. You can find "bump_limit",
 * "image_limit", and "custom_spoilers" here: <https://a.4cdn.org/boards.json>.
 * "ARCHIVE" must be the URL of a FoolFuuka archive (it should say so in the
 * footer or somewhere on the main page).
 *
 */

var BOARD = "mlp",
    BUMP_LIMIT = 500,
    IMAGE_LIMIT = 300,
    CUSTOM_SPOILERS = 1,
    ARCHIVE = "https://desuarchive.org";

/* Security PSA
 * ============
 *
 * It's a bad idea to paste random scripts into your browser's dev console.
 * There are no passwords to steal on 4chan, but scripts could still mine
 * crypto, record your IP address/posts, delete settings/hidden
 * threads/filters, steal CAPTCHAs, etc.
 *
 * This script doesn't do any of that (which is also exactly what a liar would
 * say), but in general, never paste scripts into sites that are actually
 * important (e.g. email or bank account). Okay, I'll shut up now.
 *
 *
 * Limitations
 * ===========
 *
 * - The archive doesn't say if a file was deleted, so deleted files will
 *   appear as normal.
 * - Quotelinks to deleted posts appear as cross-thread links and are crossed
 *   out when you hover over them.
 * - since4pass is not supported.
 *
 */

function reanimateThread(threadId, showDeleted) {
    // https://foolfuuka.readthedocs.io/en/latest/code_guide/documentation/api.html#thread
    $.get(`${ARCHIVE}/_/api/chan/thread/?board=${BOARD}&num=${threadId}`, {
        onload: function () {
            _reanimateThread(this.responseText, threadId, showDeleted);
        },
        onerror: function () {
            console.log("Could not fetch thread:", this.status, this.statusText);
        }
    });
}

function _reanimateThread(responseText, threadId, showDeleted) {
    let response = JSON.parse(responseText);
    if ("error" in response) {
        console.log("Error:", response.error);
        return;
    }

    let thread = response[threadId],
        fragment = document.createDocumentFragment(),
        replies = 0,
        images = 0,
        uniqueIps;

    // Prevent boardBlock from showing up
    Main.board = BOARD;

    if ("exif" in thread.op && thread.op.exif !== null) {
        // Desuarchive
        let exif = JSON.parse(thread.op.exif);
        if ("uniqueIps" in exif) {
            uniqueIps = exif.uniqueIps;
        }
    } else if (
        "extra_data" in thread.op &&
        thread.op.extra_data !== null &&
        "uniqueIps" in thread.op.extra_data
    ) {
        // 4plebs
        uniqueIps = thread.op.extra_data.uniqueIps;
    } else if (
        thread.op.media !== null &&
        "exif" in thread.op.media &&
        thread.op.media.exif !== null
    ) {
        // Archive of Sins
        uniqueIps = JSON.parse(thread.op.media.exif).uniqueIps;
    }

    // Setup custom spoiler
    Parser.setCustomSpoiler(BOARD, CUSTOM_SPOILERS);

    // Add OP (not counted in the reply and image counts)
    fragment.appendChild(parsePost(thread.op));

    // Add replies
    for (let postId in thread.posts) {
        let post = thread.posts[postId];
        if (!showDeleted && post.deleted === "1") continue;
        // Always ignore ghost posts
        if (post.subnum !== "0") continue;
        fragment.appendChild(parsePost(post));
        replies++;
        if (post.media !== null) images++;
    }

    // Insert posts
    let threadEl = document.querySelector(".thread");
    threadEl.id = "t" + threadId;
    threadEl.textContent = "";
    threadEl.appendChild(fragment);

    // Add post menus, backlinks, etc.
    Parser.parseThread(threadId, -(replies + 1));

    // Update thread stats
    if (Config.threadStats) {
        ThreadStats.update(
            replies,
            images,
            uniqueIps,
            replies >= BUMP_LIMIT,
            images >= IMAGE_LIMIT
        );
    }
}

// admin_highlight is not supported as it's indistinguishable from admin
var CAPCODES = {
    A: "admin",
    D: "developer",
    F: "founder",
    G: "manager",
    M: "mod",
    N: undefined
};

// Create a post element from an archive object
function parsePost(archive) {
    let post = {
        no: parseInt(archive.num),
        now: archive.fourchan_date + ":" + ("0" + archive.timestamp % 60).slice(-2),
        name: archive.name,
        trip: archive.trip,
        com: processComment(archive.comment_processed),
        time: archive.timestamp
    };

    let isOP = archive.op === "1";
    if (isOP) {
        post.sub = archive.title || "";
        post.resto = 0;
        post.sticky = parseInt(archive.sticky);
        post.closed = parseInt(archive.locked);
        post.id = archive.poster_hash;
        post.capcode = CAPCODES[archive.capcode];
        post.country = archive.poster_country;
        post.country_name = archive.poster_country_name || "";

        // Only /f/ has tags. This works for 4plebs, at least.
        if (
            archive.media !== null &&
            "exif" in archive.media &&
            archive.media.exif !== null
        ) {
            let exif = JSON.parse(archive.media.exif);
            if ("Tag" in exif) {
                post.tag = exif.Tag;
            }
        }
    } else {
        post.resto = parseInt(archive.thread_num);
    }

    if (archive.media !== null) {
        let mediaFilename = archive.media.media_filename.split(".");

        post.filename = mediaFilename[0];
        post.ext = "." + mediaFilename[1];
        post.w = parseInt(archive.media.media_w);
        post.h = parseInt(archive.media.media_h);
        post.tn_w = parseInt(archive.media.preview_w);
        post.tn_h = parseInt(archive.media.preview_h);
        post.tim = parseInt(archive.media.preview_orig.slice(0, -5));
        post.md5 = archive.media.media_hash;
        post.fsize = parseInt(archive.media.media_size);
        post.spoiler = parseInt(archive.media.spoiler);
    }

    let postEl = Parser.buildHTMLFromJSON(post, BOARD, isOP);
    if (isOP) {
        // We use standalone = true so that postType = "op", but this means we have
        // to remove replySpan (and the empty text node before it).
        let replySpan = postEl.querySelector(".replylink").parentNode;
        replySpan.parentNode.removeChild(replySpan.previousSibling);
        replySpan.parentNode.removeChild(replySpan);
    }
    if (archive.media !== null) {
        // Fix links to full image
        for (let link of postEl.querySelectorAll(".file a")) {
            link.href = archive.media.media_link;
        }
        // Fix thumbnail link if the image isn't spoilered
        let thumbnail = postEl.querySelector(".fileThumb:not(.imgspoiler) img");
        if (thumbnail !== null) {
            thumbnail.src = archive.media.thumb_link;
        }
    }

    return postEl;
}

function processComment(com) {
    // Slow, but it should be good enough.
    return com
        // Greentext
        .replace(/<span class="greentext"/g, '<span class="quote"')
        // Quotelinks
        .replace(/<a href=".+?(\d+)\/?" class="backlink( op)?"/g, '<a href="#p$1" class="quotelink"')
        // Cross-board links
        .replace(/>&gt;&gt;&gt;/g, ' class="quotelink">&gt;&gt;&gt;')
        // Clean regular links
        .replace(/<a href="([^"]+)" target="_blank" rel="nofollow">[^>]+<\/a>/g, "$1");
}