server.js

var express = require("express");
var app = express();
var path = require("path");
const fs = require("fs");
var WebTorrent = require("webtorrent");
var client = new WebTorrent();
let dataFile = require("./torrent.json");
let torrentInfo = [];
function downloadTorrent(magnet) {
  try {
    client.add(magnet, { path: "test" }, function (torrent) {
      torrent.on("done", function () {
        console.log("torrent download finished");
      });
      torrent.on("download", function (bytes) {
        let torrentid = torrentInfo.findIndex(
          (info) => info.infoHash === torrent.infoHash
        );
        if (torrentid >= 0) {
          torrentInfo[torrentid].downloadSpeed = torrent.downloadSpeed;
          torrentInfo[torrentid].progress = torrent.progress;
        } else {
          info = {
            infoHash: torrent.infoHash,
            downloadSpeed: torrent.downloadSpeed,
            progress: torrent.progress,
            name: torrent.name,
          };
          torrentInfo.push(info);
        }
        //console.log(torrentInfo);
        //console.log('just downloaded: ' + bytes)
        //console.log(torrent.infoHash);
        //console.log("total downloaded: " + torrent.downloaded + " bytes");
        //console.log('download speed: ' + torrent.downloadSpeed)
        //console.log("progress: " + torrent.progress);
        //res.send({ status: torrent.progress.toString() });
      });
      torrent.on("error", function (err) {
        res.send(err);
      });
    });
  } catch (err) {
    console.error("got error", err);
  }
}
//add new magnet into torrent.json
app.get("/add", function (req, res) {
  let magnet = req.query.magnet;
  //get magnet via url, put it in the torrent.json
  //download it
  if (magnet != null) {
    downloadTorrent(magnet);
    let data = {};
    let torrent = null;
    data = fs.readFileSync("torrent.json");
    torrent = JSON.parse(data);
    let urldecode = decodeURI(magnet);
    data = {
      name: "",
      magnet: urldecode,
      id: torrent["data"].length,
    };
    torrent["data"].push(data);

    torrentstr = JSON.stringify(torrent);
    fs.writeFile("torrent.json", torrentstr, (err) => {
      if (err) throw err;
      console.log("Data written to file");
    });
    res.send("added to torrent.json");
  }
});
//download all torrents saved on torrent.json
app.get("/main", function (req, res) {
  fs.readFile("torrent.json", (err, data) => {
    if (err) throw err;
    let torrent = JSON.parse(data);
    torrent.data.map((torrent) => {
      //console.log(torrent.magnet);
      downloadTorrent(torrent.magnet);
    });
    res.send("finished");
  });
});
//shows information about downloaded torrents
app.get("/info", function (req, res) {
  if (torrentInfo.length === 0) {
    res.send("no downloaded torrent info is provided");
  } else {
    res.set({
      "Content-Type": "text/json",
    });
    res.send(torrentInfo);
  }
});
app.get("/read", function (req, res) {
  fs.readFile("torrent.json", (err, data) => {
    if (err) throw err;
    let torrent = JSON.parse(data);
    console.log(torrent.data[0]);
  });
});
//parses torrent.json
app.get("/jsontest", function (req, res) {
  fs.readFile("torrent.json", (err, data) => {
    if (err) throw err;
    let torentFiles = JSON.parse(data);
    console.log(torentFiles);
  });
});
app.get("/parse", function (req, res) {
  console.log(dataFile.data[0].name);
  res.send(dataFile.data[1].name);
});
//outputs torrent.json
app.get("/torrent.json", function (req, res) {
  res.sendFile(path.resolve("torrent.json"));
  res.set("Content-Type", "text/json");
});

app.post("/submit-data", function (req, res) {
  res.send("POST Request");
});

app.put("/update-data", function (req, res) {
  res.send("PUT Request");
});

app.delete("/delete-data", function (req, res) {
  res.send("DELETE Request");
});

var server = app.listen(5000, function () {
  console.log("Node server is running..");
});