guestbook.js

const { replace_strings } = require("./utils.js");

// guestbook server
const config = {
  port: 1339,
  host: "localhost",
  postsppg: 5, // posts per page
  limits: {
    page_index: 10,
    comment: 250,
    name: 30,
    lines: 10,
  },
  postsfilename: "posts.json",
};

const fs = require("fs");
const express = require("express");
const geoip = require("fast-geoip");
const app = express();
app.set("trust proxy", true);
app.use(express.json());

const NOTO_EMOJI = `<link href="https://fonts.googleapis.com/css2?family=Noto+Color+Emoji&display=swap" rel="stylesheet">`;

try {
  fs.accessSync(config.postsfilename, fs.constants.F_OK);
} catch (err) {
  console.log(config.postsfilename, "file missing, creating");
  fs.writeFileSync(config.postsfilename, "[]", {
    encoding: "utf8",
    flush: true,
  });
}
const posts_raw = fs.readFileSync(config.postsfilename, { encoding: "utf8" });
let posts;
try {
  posts = JSON.parse(posts_raw);
} catch (e) {
  console.error("error while parsing posts file:", e);
  console.error("contents of file:", posts_raw);
}

const save_posts = () => {
  try {
    fs.writeFileSync(config.postsfilename, JSON.stringify(posts), {
      encoding: "utf8",
      flush: true,
    });
  } catch (e) {
    console.error(e);
  }
};

const escape_tags = (str) => {
  return str
    .replace(/\&/g, "&amp;")
    .replace(/\</g, "&lt;")
    .replace(/\>/g, "&gt;")
    .replace(/\"/g, "&quot;")
    .replace(/\'/g, "&#x27;")
    .replace(/\//g, "&#x2F;");
};

const BASE = fs.readFileSync("BASE.html", { encoding: "utf8" });
const GB_BASE = fs.readFileSync("GB_BASE.html", { encoding: "utf8" });
const POST_BASE = fs.readFileSync("GB_BASE_POST.html", { encoding: "utf8" });
const PAGE_INDEX = (cur_pg) =>
  [...Array(Math.ceil(posts.length / config.postsppg)).keys()]
    .map((i) => `<a href="guestbook?pg=${i}" style="margin-top: 10px;${cur_pg == i ? "color:white" : ""}">${i + 1}</a>`)
    .join("<span> | </span>");

const gen_page = async (pg, is_windows_client = false) => {
  posts.sort((a, b) => b.time - a.time);
  let p = posts.slice(config.postsppg * pg, config.postsppg * pg + config.postsppg).map(async (p) => {
    let geo, flag;
    if (p.showflag) {
      geo = await geoip.lookup(p.ip);
      flag = geo
        ? `${String.fromCodePoint(geo.country.charCodeAt(0) - 0x41 + 0x1f1e6)}${String.fromCodePoint(geo.country.charCodeAt(1) - 0x41 + 0x1f1e6)}`
        : "";
    }

    return replace_strings(
      {
        NAME: escape_tags(p.name) + (p.showflag ? flag : ""),
        COMMENT: escape_tags(p.comment),
        TIME: p.time,
      },
      POST_BASE,
    );
  });

  let o = replace_strings(
    {
      POSTS: (await Promise.all(p)).join(""),
      PGNUM: pg,
    },
    GB_BASE,
  );
  return o + `<div style="max-width:300px">${PAGE_INDEX(parseInt(pg))}</div>`;
};

app.get("/page", async (req, res) => {
  let page = req.query.pg ? req.query.pg.replace(".html", "") : 0;

  const ua = req.headers["user-agent"];
  const is_windows_client = ua ? ua.match(/(Windows NT)|(Win64)/) : false;

  let out = await gen_page(page);

  if (is_windows_client) out = NOTO_EMOJI + out;

  res.set("Content-Type", "text/html");
  res.send(out);
});

app.get("/guestbook", async (req, res) => {
  let page = req.query.pg ? req.query.pg.replace(".html", "") : 0;
  const ua = req.headers["user-agent"];
  const is_windows_client = ua ? ua.match(/(Windows NT)|(Win64)/) : false;

  let out = replace_strings({ ID: "guestbook", PAGE: await gen_page(page), TITLE: "guestbook" }, BASE);

  if (is_windows_client)
    out = [out.slice(0, out.indexOf("</head>")), NOTO_EMOJI, out.slice(out.indexOf("</head>") + "</head>".length)].join(
      "",
    );

  res.set("Content-Type", "text/html");
  res.send(out);
});

const raise_error = (msg, res) => {
  res.status(400);
  res.send(msg);
};
app.post("/post", (req, res) => {
  if (!req.body.comment) return raise_error("you comment cant be empty, write something!", res);
  if (req.body.comment.length > config.limits.comment)
    return raise_error(`comment can't be longer than ${config.limits.comment} characters`, res);
  if (req.body.name.length > config.limits.name)
    return raise_error(`name can't be longer than ${config.limits.name} characters`, res);
  let last_post_by_ip = posts.find((p) => p.ip == req.ip);
  if (last_post_by_ip && last_post_by_ip.time + 60 > Math.round(Date.now() / 1000))
    return raise_error("you can only post once per minute to prevent spam :3", res);
  if (req.body.comment.split("\n").length > config.limits.newlines)
    return raise_error(`you cant have more than ${config.limits.newlines} newlines`, res);

  posts.push({
    name: req.body.name ? req.body.name : "anon",
    comment: req.body.comment,
    showflag: typeof req.body.showflag == "boolean" ? req.body.showflag : false,
    time: Math.round(Date.now() / 1000),
    ip: req.ip,
  });
  save_posts();
  res.send("wazza");
  console.log("post made");
});

app.listen(config.port, config.host, () => {
  console.log(`listening on ${config.port}`);
});